GMATGuruNY posted a reply to If the original price of an item in a retail store is marked in the Data Sufficiency forum
“Let the original price = 100. Then the markup = (m/100)*100 = m. The resulting price = 100+m. The subsequent discount = d/100*(100+m) = d + md/100 Thus, the total percent change = percent increase - percent decrease = m - d - md/100. For the final price to be greater than the original price, ...”
Today
GMATGuruNY posted a reply to In triangle ABC, point X is the midpoint of side AC and poin in the Data Sufficiency forum
“http://s7.postimage.org/6u5drpql3/triangle_RCS_1.jpg Triangles RCS and ABC: Side RC = 1/4(AC). Side SC = 1/4(BC). The two triangles share angle BCA. Triangles with a shared angle (BCA) formed by corresponding sides in the same proportion (RC:AC = 1:4, SC:BC = 1:4) are SIMILAR. Thus, ...”
Today
GMATGuruNY posted a reply to A and B start from Opladen and Cologne respectively at the in the Problem Solving forum
“When two elements travel at different speeds, their TIME RATIO to travel the same distance will always be the same. If A takes 1/2 as long as B to travel 10 miles, then A will take 1/2 as long as B to travel 1000 miles. If A takes 3 times as long as B to travel 500 miles, then A will take three ...”
Today
GMATGuruNY posted a reply to Flor is choosing three of five colors of paint to use for in the Problem Solving forum
“Let the 5 colors be GYABC. From the 5 colors, the number of ways to choose 3 = 5C3 = (5*4*3)/(3*2*1) = 10. Of these 10 combinations, 3 are not allowed: GYA GYB GYC Subtracting these 3 bad combinations, we get: 10-3 = 7. The correct answer is A.”
Today
Brent@GMATPrepNow posted a reply to A scientist has 400 units of a 6% phosphoric acid solution, in the Problem Solving forum
“We can solve this question with the weighted averages formula: Weighted average of groups combined = (group A proportion)(group A average) + (group B proportion)(group B average) + (group C proportion)(group C average) + ... Let x = the number of units of 12% phosphoric acid solution needed ...”
Yesterday
Brent@GMATPrepNow posted a reply to If a = 15! + 13, which of the following are factors of a? I in the Problem Solving forum
“Here''s a similar question to practice with: https://www.beatthegmat.com/divisibility-t111432.html Cheers, Brent”
Yesterday
Brent@GMATPrepNow posted a reply to Phone plan A charges $1.25 for the first minute and $0.15 in the Problem Solving forum
“Phone plan A charges $1.25 for the first minute and $0.15 for every minute thereafter. Let x = total duration of phone call (in minutes) So, the cost of an x-minute call = $1.25 + ($0.15)(x - 1) ASIDE: I created the expression ($0.15)(x - 1) because we pay $1.25 for the FIRST minute. So, if x = ...”
Yesterday
Brent@GMATPrepNow posted a reply to A magician has five animals in his magic hat: 3 doves and 2 in the Problem Solving forum
“Let''s apply probability rules First notice that, to get a matched pair, we can select 2 doves or 2 rabbits. So, P(matched pair) = P(1st pick is rabbit AND 2nd pick is rabbit OR 1st pick is dove AND 2nd pick is dove) We can now apply our AND and OR rules to get: P(matched pair) = x P(2nd ...”
Yesterday
GMATGuruNY posted a reply to If a = 15! + 13, which of the following are factors of a? I in the Problem Solving forum
“MULTIPLE OF X + MULTIPLE OF X = MULTIPLE OF X. MULTIPLE OF X + NON-MULTIPLE OF X = NON-MULTIPLE OF X. Since the prime-factorization of 15! includes 13, we get: a = 15! + 13 = multiple of 13 + multiple of 13 = multiple of 13. Since a is a multiple of 13, option I is a factor of a. Eliminate ...”
Yesterday
GMATGuruNY posted a reply to If a coin has an equal probability of landing heads up or ta in the Problem Solving forum
“P(H) = 1/2. P(T) = 1/2. One way to get exactly 1 heads in 3 flips: P(HTT) = 1/2 * 1/2 * 1/2 = 1/8. Since H can appear in a total of 3 positions -- 1st flip, 2nd flip, or 3rd flip -- we multiply by 3: 1/8 * 3 = 3/8 = 0.375. The correct answer is C.”
Yesterday
GMATGuruNY posted a reply to A magician has five animals in his magic hat: 3 doves and 2 in the Problem Solving forum
“AND means MULTIPLY. OR means ADD. Case 1: 2 doves P(1st animal is a dove) = 3/5. (Of the 5 animals, 3 are doves.) P(2nd animal is a dove) = 2/4. (Of the 4 remaining animals, 2 are doves.) Since in Case 1 we need the 1st animal to be a dove AND the 2nd animal to be a dove, we MULTIPLY the ...”
Yesterday
Brent@GMATPrepNow posted a reply to If a positive integer q is divisible by both 3 and 11, then in the Problem Solving forum
“I. 14 14 is NOT divisible by 3 or 11 So, statement I is NOT true. ELIMINATE A and D III. 66 Integer q COULD equal 33 (which is divisible by 3 and 11) Since 33 is NOT divisible by 66, statement III is NOT true. ELIMINATE C and E By the process of elimination, the correct answer is B ...”
February 15, 2019
Brent@GMATPrepNow posted a reply to Kevin buys beer in bottles and cans. He pays $1.00 for each in the Data Sufficiency forum
“Target question: How many bottles of beer did Kevin buy? Given: Kevin pays $1.00 for each can of beer and $1.50 for each bottle of beer. Kevin buys a total of 15 bottles and cans of beer Let C = the NUMBER of Cans that Kevin bought Let B = the NUMBER of Bottles that Kevin bought So, we can ...”
February 15, 2019
GMATGuruNY posted a reply to What is the value of (2^{2020} + 2^{2018}) / (2^{2020}-2^{20 in the Problem Solving forum
“(2²⁰²⁰ + 2²⁰¹⁸)/(2²⁰²⁰ - 2²⁰¹⁸) = (2²⁰¹⁸)(2² + 1) / (2²⁰¹⁸)(2² - 1) = 5/3. The correct answer is B.”
February 15, 2019
GMATGuruNY posted a reply to If Rebeca drives to work at x mph she will be one minute lat in the Data Sufficiency forum
“In deference to your mother, the offensive second "c" has been removed from my solution.”
February 15, 2019
GMATGuruNY posted a reply to A certain military vehicle can run on pure Fuel X, pure Fuel in the Data Sufficiency forum
“Statement 1: X = 20 miles per gallon. Y = 40 miles per gallon. Since the mixture of X and Y in the tank allows 200 miles to be covered using 8 gallons, we get: X+Y = 200/8 = 25 miles per gallon. To determine how X and Y must be combined to yield a rate of 25 miles per gallon, use ALLIGATION. ...”
February 15, 2019
GMATGuruNY posted a reply to If Rebeca drives to work at x mph she will be one minute lat in the Data Sufficiency forum
“To make the math easier, we can replace the given values with rounder numbers, as follows: Since Rebeca arrives 1 hour late when traveling at the lower speed and 1 hour early when traveling at the higher speed, the time at the lower speed must be 2 hours greater than the time at the higher ...”
February 15, 2019
GMATGuruNY posted a reply to Which of the following numbers is closest to 100*(11-sqrt( in the Problem Solving forum
“100(11 - √119)(11 + √119) = 100(11² - √119²) = 100(121-119) = 100*2 = 200. When the correct answer is multiplied by 11+√119, the result must be as close as possible to 200. 11+√119 = 11 + (a bit less than 11) = a bit less than 22. Since 9*22 = 198, multiplying 9.2 by a bit less than ...”
February 14, 2019
GMATGuruNY posted a reply to What is the value of a^3+b^3 ? in the Data Sufficiency forum
“Statement 1: Case 1: a=0 and b=1, with the result that a+b = 0+1 = 1 In this case, a³+b³ = 0³ + 1³ = 1 Case 2: a=2 and b=-1, with the result that a+b = 2-1 = 1 In this case, a³+b³ = 2³ + (-1)³ = 7 Since a³+b³ can be different values, INSUFFICIENT. Statement 2: Case 3: a=1 and b=1, ...”
February 14, 2019
GMATGuruNY posted a reply to A group of x people is practicing levitation yoga. One-fourt in the Problem Solving forum
“Let x=12. Since 1/4 of the people rise up, the number who rise up = (1/4)(12) = 3. Since 3 people come back down, EVERYONE who rises up comes back down, with the result that all 12 people are practicing yoga on the ground. How many people are now practicing yoga on the ground? The correct ...”
February 14, 2019
Brent@GMATPrepNow posted a reply to A group of x people is practicing levitation yoga. One-fourt in the Problem Solving forum
“ One-fourth of the people rise up in the air If 1/4 of the x people are in the AIR, the remaining 3/4 of the x people are on the GROUND So, (3/4)x = number of people on the GROUND After a while, 3 of them come back down. So, the number of people on the GROUND is increased by 3 So, now ...”
February 14, 2019
Brent@GMATPrepNow posted a reply to In the figure above, polygon N has been partially covered by in the Data Sufficiency forum
“Target question: How many sides does N have? Statement 1: x + y = 45 Since all angles in a triangle add to 180°, we know that the missing angle is 135° https://i.imgur.com/oUCDRTN.png There are plenty of polygons that have at least one angle measuring 135°. Here are two: Case a: ...”
February 14, 2019
Brent@GMATPrepNow posted a reply to Which of the following expressions is equal to 2^32-2^31-2^3 in the Problem Solving forum
“2^32 - 2^31 - 2^30 = (2^30)(2^2 - 2^1 - 1) = (2^30)(4 - 2 - 1) = (2^30)(1) = 2^30 Answer: C Cheers, Brent”
February 14, 2019
Brent@GMATPrepNow posted a reply to OG L-shaped garden in the Data Sufficiency forum
“Target question: What is the value of k? Statement 1: The area of the garden is 189 square feet. Let''s drawn an auxiliary line that divides the shape into two rectangular regions A and B. https://i.imgur.com/hJBOxsO.png Regions A and B have the following measurements. ...”
February 13, 2019
Brent@GMATPrepNow posted a reply to How many integers between 18 and 3399 are multiples of 17? in the Problem Solving forum
“Let''s list the multiples of 17 that are between 18 and 3399 : 34 = 2(17) 51 = 3(17) 68 = 4(17) 85 = 5(17) . . . 3383 = 199(17) So, the number of multiples of 17 is EQUAL to the number of integers from 2 to 199 inclusive ASIDE: A nice rule says: the number of integers from x to y ...”
February 13, 2019
Brent@GMATPrepNow posted a reply to A mountain resort will hold its annual one-day snowboarding in the Problem Solving forum
“GIVEN: P(snow) = 0.7, so P(no snow) = 0.3 Let''s use the complement to solve this. That is, P(event is held) = 1 - P(event is NOT held) P(event is NOT held) = P(no snow on Saturday AND no snow on Sunday) = P(no snow on Saturday) x P(no snow on Sunday) = 0.3 x 0.3 = 0.09 So, P(event is ...”
February 13, 2019
GMATGuruNY posted a reply to How many prime factors does the number X have? 1) X is divi in the Data Sufficiency forum
“Statement combined: Case 1: X = 53*2 = 106, with the result that X is divisible by 1, 2, 53, and 106 In this case, X has TWO prime factors: 2 and 53 Case 2: X = 53³, with the result that X is divisible by 1, 53, 53², and 53³ In this case, X has only ONE prime factor: 53 Since the number of ...”
February 13, 2019
Brent@GMATPrepNow posted a reply to The product P of two prime numbers is between 9 and 55. in the Problem Solving forum
“Prime numbers that are greater than 2 but less than 6: 3, 5 Prime numbers that are greater than 13 but less than 25: 17, 19, 23 Scan the answer choices . . . E) 51 = 3 x 17 PERFECT! Answer: E Cheers, Brent”
February 12, 2019
GMATGuruNY posted a reply to A terminating decimal is a number with a finite number of in the Data Sufficiency forum
“A fraction will yield a terminating decimal if -- when the fraction is fully reduced -- the prime-factorization of its denominator includes only 2''s and or 5''s. Statement 1: Let x = an odd multiple of 5. Since the next largest odd multiples of 5 will be x+10 and x+20, we get: p = x + (x+10) ...”
February 12, 2019
GMATGuruNY posted a reply to If O is the center of the circle with diameter AB and T is a in the Problem Solving forum
“A radius drawn to a tangent point yields a RIGHT ANGLE: https://i.postimg.cc/Wq6BDNH7/two-triangles-and-semicircle-1.png In the figure above: Radius OT forms a right angle at tangent point T. OA and OT are radii and thus are equal. Since OA=OT, opposite angles OAT and ATO are equal. We can ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to What is the probability that you get a pair when picking the in the Problem Solving forum
“P(select pair) = P(1st card is ANY card AND 2nd card matches 1st card) = P(1st card is ANY card) x P(2nd card matches 1st card) = 1 x 3/51 = 3/51 = 1/17 = C Aside: P(2nd card matches 1st card) = 3/51, because once 1 card is selected, there are 51 cards remaining in the deck. Among those 51 ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to At her current job, Mary gets a 1.5% raise twice per year. in the Problem Solving forum
“One approach here is to apply the COMPOUND INTEREST formula. However, if you didn''t see that the question is analogous to a COMPOUND INTEREST question, we can also solve the question by looking for a pattern. Let''s try that: Time elapsed (in years) | salary 0 | s 0.5 | (1.015)(s) 1 | ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to Of the 3,000 cars manufactured in Factory Q last year, how in the Data Sufficiency forum
“Target question: Of the 3,000 cars manufactured in Factory Q LAST YEAR, how many were still in operation at the end of the year? Neither statement provides any information about the cars manufactured LAST YEAR. Instead, we''re told about ALL of the cars ever manufactured . As such, the ...”
February 12, 2019
GMATGuruNY posted a reply to A positive 5-digit integer is called "friendly" if in the Problem Solving forum
“Total number of friendly numbers = total number of ways to arrange the 5 digits = 5! = 120. There are 5 options for the first digit: 1, 2, 3, 4, or 5. 120/5 = 24. Thus, the 120 friendly numbers are composed of five 24-number ranges, as follows: The integers beginning with 1 constitute friendly ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to In the figure given, x = 3(y-z). What is the value of x? in the Problem Solving forum
“Since angles on a LINE add to 180°, . . . https://i.imgur.com/kAdhC7N.png . . . we know that x + z = 180 Subtract x from both sides to get: z = 180 - x Since angles in a CIRCLE add to 360°. . . https://i.imgur.com/l1SKqw5.png . . . we know that 60 + (180 - x) + y = 360 Simplify left ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to In the xy-coordinate plane, if the point (0,2) lies on the g in the Problem Solving forum
“KEY CONCEPT: In order for a point to be ON a line, the x- and y-coordinates of the point must satisfy the equation of that line So, for example, the point (3,7) lies ON the line defined by the equation y = 2x + 1, because x = 3 and y = 7 satisfy the equation y = 2x + 1 That is, 7 = 2(3) + 1 ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to Set S consists of n consecutive integers, where n > 1. in the Data Sufficiency forum
“ Given: Set S consists of n consecutive integers, where n > 1. Target question: What is the value of n? IMPORTANT: Notice that the two statements are VERY SIMILAR. That is, if the sum of the values is 14 (statement 2), then it is guaranteed that the sum is divisible by 7 (statement 1). ...”
February 12, 2019
GMATGuruNY posted a reply to How many numbers between 1 and 200, inclusive, have a 2 in in the Problem Solving forum
“An integer is divisible by 4 if its last two digits form a multiple of 4. Two-digit multiples of 4 with a units digit of 2: 12, 32, 52, 72, 92 Since the last two digits must be one of the options above, between 1 and 200 there are 10 integers that have a units digit of 2 and are divisible by 4: ...”
February 12, 2019
GMATGuruNY posted a reply to If triangles ABC and CDE are each equilateral, what is the s in the Data Sufficiency forum
“Statement 1: Case 1: AC = 10 and CE = 15, with the result that AE = 10+15 = 25 In this case, ABC + CDE = (10+10+10) + (15+15+15) = 75. Case 2: AC= 5 and CD = 20, with the result that AE = 5+20 = 25 In this case, ABC + CDE = (5+5+5) + (20+20+20) = 75. Since the sum of the perimeters is the same ...”
February 12, 2019
GMATGuruNY posted a reply to If m is a positive odd integer, what is the average (arithme in the Data Sufficiency forum
“For any EVENLY SPACED SET: average = median Statement 1: Here, the set consists of consecutive multiples of 3 and thus is evenly spaced. Case 1: 3, 6, 9 Average = median = 6. Case 2: 6, 9, 12 Average = median = 9. Since different averages are possible, INSUFFICIENT. Statement 2: Case ...”
February 12, 2019
GMATGuruNY posted a reply to If there is a 20% chance of rain every day for the next 7 in the Problem Solving forum
“Options D and E should appear as shown below: P(exactly n times) = P(one way) * all possible ways. Let R = rain and N = no rain. Since P(R) = 20% = 2/10, P(N) = 80% = 8/10 = 2³/10. P(one way): One way to get exactly 2 days of rain is to have rain on the first 2 days but not on the ...”
February 12, 2019
Brent@GMATPrepNow posted a reply to A computer chip manufacturer expects the ratio of the number in the Problem Solving forum
“Let''s find some TOTALS for all 4 shipments combined. There are 51,000 chips altogether There are 17 defective chips altogether. So, 17/51000 of the chips are defective. (notice that 17 divides nicely into 51000!) SIMPLIFY: 1/3000 of the chips are defective So, if we have a shipment of ...”
February 11, 2019
Brent@GMATPrepNow posted a reply to If O is the center of the circle with diameter AB and T is a in the Problem Solving forum
“Since angles in a triangle add to 180°, we know that the missing angle = (90 - 2x)° https://i.imgur.com/FcSiZi2.png Aside: Notice that (90 - 2x)° + 90° + 2x° =180° Since angles on a line add to 180°, we know that the missing angle = (90 + 2x)° https://i.imgur.com/9Z5ULFo.png ...”
February 11, 2019
Brent@GMATPrepNow posted a reply to tough geo. problem in the Data Sufficiency forum
“Target question: What is the length of side BC? Statement 1: Line segment AD has length 6. BEFORE we deal with statement 1, let''s see what information we can add to the diagram. For example, since ∆BDC has 2 equal angles (of 2x°), we know that side BD = side BC: ...”
February 11, 2019
Brent@GMATPrepNow posted a reply to What is the area of a right triangle? in the Data Sufficiency forum
“Target question: What is the area of a right triangle? Statement 1: The length of one side is 3 Knowing the length of only 1 side will not help us answer the target question with certainty. Statement 1 is NOT SUFFICIENT Statement 2: The length of one side is 4 NOT SUFFICIENT (same ...”
February 11, 2019
Brent@GMATPrepNow posted a reply to If x=0.2, then what is the value of x^3-1/x-1? in the Problem Solving forum
“Some spaces and/or brackets would definitely help here. Do you mean x^3 - 1/x - 1 or x^3 - 1/(x - 1) or (x^3 - 1)/(x - 1)?? Cheers, Brent”
February 11, 2019
Brent@GMATPrepNow posted a reply to If n and p are integers, is p > 0? in the Data Sufficiency forum
“ Given: n and p are integers Target question: Is p > 0? Statement 1: n + 1 > 0 No information about p. Statement 1 is NOT SUFFICIENT Statement 2: np > 0 There are several values of n and p that satisfy statement 2. Here are two: Case a: n = 1 and p = 1. In this case, ...”
February 11, 2019
Brent@GMATPrepNow posted a reply to If x and y are integers, is x^2-y^2 odd? in the Data Sufficiency forum
“Some important rules: #1. ODD +/- ODD = EVEN #2. ODD +/- EVEN = ODD #3. EVEN +/- EVEN = EVEN #4. (ODD)(ODD) = ODD #5. (ODD)(EVEN) = EVEN #6. (EVEN)(EVEN) = EVEN Target question: Is x² - y² odd? IMPORTANT: Notice that we can factor x² - y² to get: x² - y² = (x + y)(x - y) ...”
February 10, 2019
Brent@GMATPrepNow posted a reply to In a group of 100 adults, 75 percent of the women are in the Problem Solving forum
“GIVEN: 75% women are LEFT handed This also tells us that 25% women are RIGHT handed GIVEN: There are 12 right-handed women Let W = total number of women in the group So, 25% of W = 12 Rewrite as: 0.25W = 12 Solve: W = 12/0.25 = 48 So, there are 48 women So, the number of men in the ...”
February 10, 2019
GMATGuruNY posted a reply to Working together, Machine A and Machine B can produce a tota in the Data Sufficiency forum
“Since A+B take 4 hours to produce 200 widgets, the combined rate for A+B = w/t = 200/4 = 50 widgets per hour. To determine A''s time to produce 200 widgets, we need to know A''s rate. Question stem, rephrased: What is A''s rate? Statement 1: Since B takes 5 hours to produce 50 widgets, ...”
February 10, 2019
Brent@GMATPrepNow posted a reply to Triangle XYZ is an isosceles right triangle. If side XY is l in the Problem Solving forum
“Triangle XYZ is an isosceles right triangle. Let''s sketch an isosceles right triangle: https://i.imgur.com/N3UOppf.png Side XY is longer than side YZ Since the hypotenuse is the longest side of a right triangle, side XY must be the hypotenuse. Add this to our diagram: ...”
February 9, 2019
GMATGuruNY posted a reply to Triangle XYZ is an isosceles right triangle. If side XY is l in the Problem Solving forum
“The sides of an isosceles right triangle are in the following ratio: x - x - x√2, where x and x constitute the base and height and x√2 is the hypotenuse. Since the triangle has a base of x, a height of x, and an area of 16, we get: (1/2)(x)(x) = 16 x² = 32 x = √32 Since XY is longer ...”
February 9, 2019
GMATGuruNY posted a reply to Machines X and Y work at their respective constant rates. Ho in the Data Sufficiency forum
“Statement 1: Time and rate are RECIPROCALS. Since X and Y together take 2/3 as long as X alone, X and Y together work 3/2 as fast as X alone. Thus, if X''s rate alone = 2 units per hour, then X and Y''s combined rate = (3/2)(2) = 3 units per hour, implying that Y''s rate alone = 3-2 = 1 unit ...”
February 9, 2019
GMATGuruNY posted a reply to Seven children — A, B, C, D, E, F, and G — are going to in the Problem Solving forum
“Since A and B must occupy adjacent positions, consider AB a single element in the arrangement. The number of ways to arrange the 6 elements AB, C, D, E, F and G = 6! = 720. In 1/2 of these arrangements, C will be to the LEFT of AB. In the remaining 1/2 of these arrangements,C will be to the ...”
February 9, 2019
GMATGuruNY posted a reply to Is abc at least 4? in the Data Sufficiency forum
“Nice problem, Fabio! Statement 1: Case 1: a=4, b=1 and c=1, with the result that b+c≥2 In this case, abc = 4, so the answer to the question stem is YES. Case 2: a=0, b=1 and c=1, with the result that b+c≥2 In this case, abc = 0, so the answer to the question stem is NO. Since the answer ...”
February 8, 2019
GMATGuruNY posted a reply to What is the remainder when the positive integer n is divided in the Data Sufficiency forum
“Statement 1: If n=5, then the remainder when n is divided by 6 = 5/6 = 0 R5. If n=10, then the remainder when n is divided by 6 = 10/6 = 1 R4. Since different remainders are possible, INSUFFICIENT. Statement 2: Since n is a multiple of 12, n must also be a multiple of 6, with the result that ...”
February 8, 2019
GMATGuruNY posted a reply to An electrical supplies store sells 140 power stabilizer in the Problem Solving forum
“Since at least $5600 in profit must be earned by 140 units, the minimum required markup per unit = 5600/140 = $40. Thus, the minimum selling price = (cost per unit) + (minimum required markup per unit) = 16+40 = 56. The correct answer is D.”
February 8, 2019
Brent@GMATPrepNow posted a reply to Out of 2 broken TV sets and 6 fixed TV sets in Joe's Fix-My- in the Problem Solving forum
“There are 8 TV''s in total 2 are broken 6 are fixed We want to find P(at least one TV is broken) When it comes to probability questions involving at least, it''s often best to try using the complement. That is, P(Event A happening) = 1 - P(Event A not happening) So, here we get: P(getting ...”
February 8, 2019
Brent@GMATPrepNow posted a reply to An electrical supplies store sells 140 power stabilizer in the Problem Solving forum
“Let x = the selling price per unit So, x - 16 = the PROFIT on ONE unit And 140(x - 16) = the PROFIT on the sale of 140 units (aka the weekly profit) What is the minimum selling price per unit that will ensure a weekly profit of at least $5600 from sales of power stabilizers? In other words, ...”
February 8, 2019
Brent@GMATPrepNow posted a reply to What is the remainder when the positive integer n is divided in the Data Sufficiency forum
“Target question: What is the remainder when the positive integer n is divided by 6? Statement 1: n is multiple of 5 Let''s TEST some values. There are several values of n that satisfy statement 1. Here are two: Case a: n = 10. In this case, the answer to the target question is the ...”
February 8, 2019
GMATGuruNY posted a reply to In the xy coordinate plane, line L and line K intersect at in the Data Sufficiency forum
“Statement 1: The product of the x-intercepts of line L and K is positive. K has a negative x-intercept, L has a negative x-intercept, the product of the slopes is positive: http://s4.postimage.org/ie5nbe78/lines_l_and_k_1.jpg K has a positive x-intercept, L has a positive x-intercept, the ...”
February 8, 2019
GMATGuruNY posted a reply to If x and y are positive integers, is x an even integer? in the Data Sufficiency forum
“Statements combined: Case 1: x=1 and y=1, with the result that x(y+5) = 6 and 6y²+41y+25 = 72 In this case, x is ODD, so the answer to the question stem is NO. Case 2: x=2 and y=1, with the result that x(y+5) = 12 and 6y²+41y+25 = 72 In this case, x is EVEN, so the answer to the question ...”
February 7, 2019
GMATGuruNY posted a reply to What is the average (arithmetic mean) of x and y? in the Data Sufficiency forum
“SUM = (COUNT)(AVERAGE). Statement 1: x+y+k = (count)(average) = 3*7 = 21. No way to determine the value of x+y. INSUFFICIENT. Statement 2: x+y+3k = (count)(average) = 3*13 = 39. No way to determine the value of x+y. INSUFFICIENT. Statements combined: Subtracting x+y+k=21 from ...”
February 7, 2019
GMATGuruNY posted a reply to If a and b are integers, is a + b + 3 an odd integer? (1) in the Data Sufficiency forum
“a+b+3 = ODD only if a and b are both odd or both even. Question stem, rephrased: Are a and b both odd or both even? Statement 1: ab = ODD implies that a and b are both odd. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: a-b = EVEN implies that a and b are either ...”
February 7, 2019
Brent@GMATPrepNow posted a reply to What is the sum of the digits of the number (2^{2018})(5^{20 in the Problem Solving forum
“Useful rule: (x^k)(y^k) = (xy)^k Example: (3^4)(7^4) = 21^4 (2^2018)(5^2019)(3^2) = (2^2018)((5^2018)(5^1))(3^2) = (2^2018)(5^2018)(5^1))(3^2) = (10^2018)(5^1))(3^2) = (10^2018)(5)(9) = (10^2018)(45) We know that (10^2018) = 1 followed by 2018 zeros So, (10^2018)(45) = 45 followed by ...”
February 7, 2019
Brent@GMATPrepNow posted a reply to If a and b are integers, is a + b + 3 an odd integer? (1) in the Data Sufficiency forum
“Target question: Is a + b + 3 an odd integer? Given: a and b are integers Statement 1: ab is an odd integer. Some useful rules: 1. ODD - ODD = EVEN 2. ODD - EVEN = ODD 3. EVEN - ODD = ODD 4. EVEN - EVEN = EVEN 5. (ODD)(ODD) = ODD 6. (ODD)(EVEN) = EVEN 7. (EVEN)(EVEN) = EVEN ...”
February 7, 2019
Brent@GMATPrepNow posted a reply to The sides of a right triangle are consecutive even integers, in the Problem Solving forum
“GIVEN: p = length of the longest side Since the side lengths are consecutive even integers, we can say: p - 2 = length of the 2nd longest side p - 4 = length of the shortest side NOTE: The longest side is the HYPOTENUSE. So, p = length of the HYPOTENUSE And p - 2 = length of one leg of ...”
February 7, 2019
Brent@GMATPrepNow posted a reply to In the diagram above, O is the center of the circle. What is in the Data Sufficiency forum
“Target question: What is the length of chord AC? Given: O is the center of the circle If O is the center of the circle, then AB is the circle''s DIAMETER If AB is the DIAMETER, then ∠C = 90°, because ∠C is an inscribed angle containing ("holding") the diameter. So, let''s ...”
February 7, 2019
Brent@GMATPrepNow posted a reply to Ten telegenic contestants with a variety of personality diso in the Problem Solving forum
“Let''s take the task of creating the teams and break it into stages. Stage 1: Select two 5 contestants to be in tribe A Since the order in which we select the contestants does not matter, we can use combinations. We can select 5 contestants from 10 contestants in 10C5 ways 10C5 = ...”
February 7, 2019
Brent@GMATPrepNow posted a reply to We define the harmonic mean of a set of numbers as the recip in the Problem Solving forum
“What is the harmonic mean of 20 and 30? NOTE: 20 = 20/1 So, the reciprocal of 20 = 1/20 And the reciprocal of 30 = 1/30 The average of 1/20 and 1/30 = (1/20 + 1/30 )/2 = (3/60 + 2/60 )/2 = (5/60 )/2 = (5/60 )/(2/1) = (5/60 )(1/2) = 5/120 The reciprocal of 5/120 = 120/5 = 24 Answer: ...”
February 6, 2019
Brent@GMATPrepNow posted a reply to A certain bag contains red, blue, and green marbles. What is in the Data Sufficiency forum
“ Given: A certain bag contains red, blue, and green marbles. Let R = # number red marbles in the bag Let B = # number blue marbles in the bag Let G = # number green marbles in the bag Target question: What is the value of G/R? Statement 1: The number of blue marbles in the bag is two ...”
February 6, 2019
Brent@GMATPrepNow posted a reply to If x is a nonzero number, which of the three numbers x, 1/x in the Data Sufficiency forum
“ Given: x is a nonzero number Target question: Which of the three numbers x, 1/x and x² is greatest? Statement 1: -1 < x < 1 This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of x that satisfy statement 1. Here are two: Case a: x = ...”
February 6, 2019
GMATGuruNY posted a reply to In the coordinate plane, Line A has a slope of -1 and an in the Problem Solving forum
“Line A includes points (1, 0) and (a, b) and has a slope of -1. Thus: (b - 0)/(a-1) = -1 b = -a + 1 a+b = 1. The correct answer is B. The information about Line B is irrelevant.”
February 5, 2019
GMATGuruNY posted a reply to In how many ways can a 4-letter word be formed from the in the Problem Solving forum
“Alternate approach: Case 1: VVCC, where the first two letters are vowels and the last 2 letters are consonants Number of options for the first vowel = 4. (Any of the 4 vowels) Number of options for the second vowel = 3. (Any of the 3 remaining vowels) Number of options for the first consonant ...”
February 5, 2019
Brent@GMATPrepNow posted a reply to Three sisters have an average (arithmetic mean) age of 25 in the Problem Solving forum
“If the average age is 25, we can write: (sum of all 3 ages)/3 = 25 This means, the sum of all 3 ages = 75 If the median is 24, then we can express the ages in ascending order as follows: __ , 24, __ Since the sum of the ages is 75, we can MINIMIZE the age of the oldest girl by MAXIMIZING the ...”
February 5, 2019
Brent@GMATPrepNow posted a reply to A contractor combined x tons of a gravel mixture that in the Data Sufficiency forum
“Let''s use some weighted averages to solve this question Weighted average of groups combined = (group A proportion)(group A average) + (group B proportion)(group B average) + (group C proportion)(group C average) + ... Target question: What is the value of x ? Given: A contractor combined x ...”
February 4, 2019
GMATGuruNY posted a reply to A contractor combined x tons of a gravel mixture that in the Data Sufficiency forum
“x = 10% gravel y = 2% gravel. z = the MIXTURE of x and y = 5% gravel. To determine the required ratio of x to y, use ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: Plot the 3 percentages on a number line, with the percentages for x and y on the ends and the ...”
February 4, 2019
Brent@GMATPrepNow posted a reply to A committee of 6 is chosen from 8 men and 5 women so as to in the Problem Solving forum
“Since the committee must have 6 people, there are two cases that meet the given restrictions: 1) The committee has 2 men and 4 women 2) The committee has 3 men and 3 women 1) The committee has 2 men and 4 women Since the order in which we select the men and women does not matter, we can use ...”
February 4, 2019
Brent@GMATPrepNow posted a reply to Mixture problem unclear in the Problem Solving forum
“When solving mixture questions, I find it useful to sketch the solutions with the ingredients SEPARATED. Since we''re asked to find a PERCENTAGE, we can assign a "nice" value to the original volume. So, let''s say we start with 100 liters https://i.imgur.com/yt2KAw7.png As you can ...”
February 4, 2019
Brent@GMATPrepNow posted a reply to Mr. Jones spends $25 on movie tickets for a party of adults in the Data Sufficiency forum
“ Given: Mr. Jones spends $25 on movie tickets for a party of adults and children. Target question: How many children''s tickets did he buy? Statement 1: Adult movie tickets cost $3 each and children''s tickets cost $2 each. There are several scenarios that satisfy statement 1. Here are ...”
February 4, 2019
Brent@GMATPrepNow posted a reply to In a certain sock drawer, there are 4 pairs of black socks, in the Problem Solving forum
“If we remove 1 black sock, 1 gray sock, and 1 orange sock, then we still don''t have a matching sock. So, we can select 3 socks WITHOUT having a matching pair. However, if we pick ANY sock for our fourth sock, that sock MUST match one of the first 3 socks selected. Answer: A Cheers, Brent”
February 4, 2019
Brent@GMATPrepNow posted a reply to Piper bought three shirts. The three shirts cost $210 in the Data Sufficiency forum
“IMPORTANT: Notice that statements 1 and 2 provide the EXACT SAME INFORMATION. When this occurs, the correct answer is either D or E Since the information is so sparse, I have a feeling that the correct answer is E. So, I''m going to try to find two possible cases that satisfy both statements, yet ...”
February 3, 2019
Brent@GMATPrepNow posted a reply to In the graduating class of a certain college, 48 percent of in the Problem Solving forum
“I thought I''d point out that Mitch''s Double Matrix Method approach can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of students, and the two characteristics are: - male or female - younger than 25 ...”
February 3, 2019
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Data Sufficiency lesson #3: Avoiding Common Mistakes - Part I Video : https://www.youtube.com/watch?v=iACq36scVYQ Cheers, Brent”
February 3, 2019
GMATGuruNY posted a reply to Bank Depositors (GMAT Prep) in the Critical Reasoning forum
“I received a PM requesting that I respond. Premise: Insurance removes from depositors any financial incentive to find out whether the bank that holds their money is secure against failure. Conclusion: The insurance is partly responsible for the high rate of bank failures. To determine the ...”
February 3, 2019
GMATGuruNY posted a reply to In the graduating class of a certain college, 48 percent of in the Problem Solving forum
“Every student is EITHER male OR female. Every student is EITER older OR younger. For an EITHER/OR problem, use a DOUBLE MATRIX to organize the data: _______________M______F_______Total older: younger: total: Let total students = 100: _______________M______F_______Total ...”
February 3, 2019
GMATGuruNY posted a reply to Kate and Danny each have $10. Together, they flip a fair coi in the Problem Solving forum
“For every tails, Kate gets $1; for every heads, she loses $1. 0 tails, 5 heads: Kate has 10+0-5 = $5 1 tails, 4 heads: Kate has 10+1-4 = $7 2 tails, 3 heads: Kate has 10+2-3 = $9 3 tails, 2 heads: Kate has 10+3-2 = $11 4 tails, 1 heads: Kate has 10+4-1 = $13 5 tails, 0 heads: Kate has ...”
February 3, 2019
ceilidh.erickson posted a reply to If x and y are positive integers, what is the remainder when in the Data Sufficiency forum
“If x and y are positive integers, what is the remainder when 5^x is divided by y? In order to answer this question, we need some information about x and y. For some divisors of y, the value of x wouldn''t matter: if y = 5, the remainder is always 0, because any 5^x will be divisible by 5. If y = ...”
February 2, 2019
ceilidh.erickson posted a reply to On the number line, the distance between point A and point C in the Data Sufficiency forum
“With NUMBER LINE problems in DS, remember that information about distance alone does not give us information about direction. When unpacking the question, try to imagine different scenarios with the given information. Try to come up with one scenario in which C is between A and B, and one in ...”
February 2, 2019
ceilidh.erickson posted a reply to Beth has a collection of 8 boxes of clothing for a charity, in the Problem Solving forum
“When there are variables in the answer choices in a PS problem, it''s often easy to pick our own values for those variables. With averages, it''s often easiest to just treat each member of the group as the same. i.e. let''s say that in this case, we have 8 identical boxes with 12 clothing items ...”
February 2, 2019
ceilidh.erickson posted a reply to Is tutoring necessary for Verbal? in the GMAT Strategy forum
“In my opinion, no. Don''t get a tutor... yet. When students say "I don''t have much time, so I''ll get a tutor rather than studying on my own," that''s usually not a recipe for success. Tutoring is most productive when it''s supplementing significant time spent studying on your own. Tutors ...”
February 2, 2019
ceilidh.erickson posted a reply to Guidance on study plan in the GMAT Strategy forum
“Yes, this is more than enough material to get started with. Here''s what you should do: 1. Analyze the practice test you''ve taken in a lot of depth. Which areas were you weakest? Strongest? Fastest? Slowest? Decide which topics and question types need more of your time and attention. Be very ...”
February 2, 2019
Brent@GMATPrepNow posted a reply to Beth has a collection of 8 boxes of clothing for a charity, in the Problem Solving forum
“One box contains 12 items of clothing Let t, u, v, w, x, y, z = the number of items in each of the other 7 boxes Beth has a collection of 8 boxes of clothing for a charity, and the average (arithmetic mean) number of pieces of clothing per box is c. We can write: (t + u + v + w + x + y + z + ...”
February 2, 2019
Brent@GMATPrepNow posted a reply to Perpendicular lines m and n... in the Data Sufficiency forum
“ Given: Perpendicular lines m and n intersect at (0,b) Target question: What is the value of b? Statement 1: The slope of the line m is -1/2 Since line n is PERPENDICULAR to line m, we know that line n has slope 2 However, we can raise and lower the two lines so that the value of b is ...”
February 1, 2019
GMATGuruNY posted a reply to A paint crew gets a rush order to paint 80 houses in a new d in the Problem Solving forum
“Let y=0, implying that NONE of the 80 houses are painted at the original rate of x houses per week, with the result that ALL 80 houses are painted at the greater rate of (5/4)x houses per week. The total time it takes them to paint all the houses under this scenario is what fraction of the time ...”
February 1, 2019
GMATGuruNY posted a reply to Three pipes P, Q, and R are attached to a tank. P and Q indi in the Problem Solving forum
“Let the tank = 60 liters. Since P takes 3 hours to fill the 60-liter tank, P''s rate = 60/3 = 20 liters per hour. Since Q takes 4 hours to fill the 60-liter tank, Q''s rate = 60/4 = 15 liters per hour. Since R takes 5 hours to empty the 60-liter tank, R''s rate = -(60/5) = −12 liters per ...”
February 1, 2019
GMATGuruNY posted a reply to If ( x – y – 2 )^2 + ( x + z + 3 )^2 = 0, then what is t in the Problem Solving forum
“Let x=0. Plugging x=0 into (x-y-2)² + (x+z+3)² = 0, we get: (-y-2)² + (z+3)² = 0 Since neither (-y-2)² nor (z+3)² can be negative, the resulting equation is valid only if -y-2=0 and z+3=0, with the result that y=-2 and z=-3. Thus, y+z = -2 + (-3) = -5 The correct answer is E.”
February 1, 2019
GMATGuruNY posted a reply to Cars J and K are making the trip from City A to City B. Car in the Problem Solving forum
“Since J catches up to K, J and K travel the same distance. Let t = J''s time. Since K leaves 15 minutes earlier than J, K''s time = t+15. Rate and time have a RECIPROCAL RELATIONSHIP. Since K''s rate is 80% of J''s rate, the ratio of K''s rate to J''s rate = 8/10 = 4/5. Thus, the ratio of ...”
January 31, 2019
GMATGuruNY posted a reply to f(2x-1) = ( x + 2 ) / ( x – 2 ). What is f(x)? in the Problem Solving forum
“Let x=1. Plugging x=1 into f(2x-1) = ( x + 2 ) / ( x – 2 ), we get: f(2*1 - 1) = (1+2)/(1-2) f(1) = -3. When x=1, the question stem becomes: What is f(1)? Since f(1) = -3, the correct answer must yield -3 when x=1. Only A works: f(1) = (1+5)/(1-3) = 6/-2 = -3. The correct answer is A.”
January 31, 2019
GMATGuruNY posted a reply to A lecture course consists of 595 students. The students are in the Problem Solving forum
“(students per section)(number of sections) = 595 students number of sections = 595/(students per section). The equation in blue indicates that 595 must be divisible by the number of students per section. An integer is divisible by 3 only if its digit sum is a multiple of 3. The digit sum of ...”
January 30, 2019
GMATGuruNY posted a reply to Question about idioms and verbs in the Sentence Correction forum
“Correct: The contractors demolished the building to keep it from falling. Here, to keep is not an adjective modifying contractors but an ADVERB modifying demolished, expressing WHY the contractors DEMOLISHED the building. Question: WHY did the contractors demolish the building? Answer: TO KEEP it ...”
January 30, 2019
Brent@GMATPrepNow posted a reply to How many females? (GMAT Prep 2) in the Data Sufficiency forum
“Target question: What percent of the students in the class were females? Let''s use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a ...”
January 30, 2019
GMATGuruNY posted a reply to DS work rate problem in the Data Sufficiency forum
“Statement 1: Case 1: Job = 12 units Since A and B together take 4 hours to complete the 12-unit job, the combined rate for A+B = 12/4 = 3 units per hour. Since A alone takes 6 hours to complete the 12-unit job, A''s rate alone = 12/6 = 2 units per hour. B''s rate = (combined rate for A+B) - ...”
January 30, 2019
GMATGuruNY posted a reply to PS arithmetic in the Problem Solving forum
“An alternate approach is to BALLPARK. √2 ≈ 1.4 √3 ≈ 1.7 (1+√3) * √(2 + √3) ≈ (2.7)(√3.7) = (2.7)(a bit less than 2) = a bit less than 5.4. When we evaluate the answer choices, only C is a bit less than 5.4: √2(2 + √3) ≈ (1.4)(3.7) = 5.18. The correct answer is C.”
January 30, 2019
Brent@GMATPrepNow posted a reply to A doctor prescribed 18 cubic centimeters of a certain drug t in the Problem Solving forum
“We can use equivalent ratios to determine what the dosage SHOULD have been. We''ll use the ratio of drug dosage (in cubic centimeters)/body weight (in pounds) Let x = the dosage (in cubic centimeters) the patient SHOULD have received We get: 2/15 = x/120 Cross multiply to get: 15x = ...”
January 30, 2019
GMATGuruNY posted a reply to DS arithmetic in the Data Sufficiency forum
“Statement 1: The inequality implies that a is POSITIVE, allowing us to cross-multiply: 1*2 > a*1 2 > a Since 2>a and a>b>0, we get: 2>a>b>0 Thus, b<2. SUFFICIENT. Statement 2: If b=2, we get: 1/a + 1/2 = 1 1/a = 1/2 a=2 Not possible, since the prompt ...”
January 30, 2019
GMATGuruNY posted a reply to The sum of 4 different odd integers is 64. in the Data Sufficiency forum
“Statement 1: Since the numbers are EVENLY SPACED, median = sum/count: 64/4 = 16. Since the median = 16, the 4 odd integers must be as follows: 13, 15, 17, 19. Thus, the greatest of the 4 odd integers = 19. SUFFICENT. Statement 2: The 4 odd integers yielded by Statement 1 -- 13, 15, ...”
January 30, 2019
Brent@GMATPrepNow posted a reply to Marla starts running around a circular track at the same... in the Problem Solving forum
“Let t = the time (in HOURS) that it takes Marla to complete 4 more laps than Nick. So, after t hours, we can write: (Marla''s lap count) = (Nick''s lap count) + 4 Now that we have a "word equation" we need only fill in the missing information Marla completes 32 laps per hour We can ...”
January 29, 2019
GMATGuruNY posted a reply to To create a part for a certain piece of machinery, four equa in the Problem Solving forum
“The four 18-degree shaded regions = 4*18 = 72 degrees. The entire circle = 360 degrees. (shaded regions)/(entire circle) = 72/360 = 1/5. Thus: (unshaded regions)/(entire circle) = 1 - 1/5 = 4/5 = 80%. The correct answer is E.”
January 29, 2019
Brent@GMATPrepNow posted a reply to Paul, a painter, paints only flowers or cats in his notebook in the Data Sufficiency forum
“I thought I''d point out that the approach demonstrated by Fabio and Jay is known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of paintings, and the ...”
January 29, 2019
Brent@GMATPrepNow posted a reply to f(x) has the properties, f(x+y) = x + f(y) and f(0) = 5. Wha in the Problem Solving forum
“Given: f(x+y) = x + f(y) What is the value of f(100)? We need to somehow use the fact that f(0) = 5 to help us determine the value of f(100). Notice that we can rewrite 100 as 100 + 0 According to our the function f, we know that: f(100 + 0) = 100 + f(0) = 100 + 5 = 105 Answer: C ...”
January 29, 2019
Brent@GMATPrepNow posted a reply to Leila is playing a carnival game in which she is given 4 in the Problem Solving forum
“Given: P(succeeds on 1 throw) = 1/5 P(succeeds at least 3 times) = P(succeeds 4 times OR succeeds 3 times) = P(succeeds 4 times) + P(succeeds 3 times) P(succeeds 4 times) P(succeeds 4 times) = P(succeeds 1st time AND succeeds 2nd time AND succeeds 3rd time AND succeeds 4th time) = ...”
January 29, 2019
Brent@GMATPrepNow posted a reply to A waitress's income consist of her salary and tips. During in the Problem Solving forum
“APPROACH #1 - start with a convenient value of the server''s salary Let''s say her salary is $4 GIVEN: her tips were 5/4 of her salary 5/4 of $4 = $5 So, her tip total was $5 What fraction of her income for the week came from tips? Income = salary + tips = $4 + $5 = $9 Fraction = $5 /$9 ...”
January 29, 2019
Brent@GMATPrepNow posted a reply to To create a part for a certain piece of machinery, four equa in the Problem Solving forum
“IMPORTANT: the diagrams in GMAT problem solving questions are DRAWN TO SCALE unless stated otherwise. We can use this fact to solve the question by simply "eyeballing" the diagram. The question is basically asking us to determine what percent of the circle is NOT shaded. Well, ...”
January 29, 2019
Brent@GMATPrepNow posted a reply to If (x+y)/z = -2, is x positive? in the Data Sufficiency forum
“Target question: Is x positive? Given: (x + y)/z = -2 Since the question asks about the variable x, let''s solve this equation for x. (x + y)/z = -2 So, x + y = -2z And, x = -2z - y This allows us to REPHRASE the target question.... REPHRASED target question: Is -2z - y positive? ...”
January 29, 2019
Brent@GMATPrepNow posted a reply to The table above shows the GPA of 20 students last semester. in the Problem Solving forum
“---------------ASIDE-------------- A little extra background on standard deviations above and below the mean If, for example, a set has a standard deviation of 4, then: 1 standard deviation = 4 2 standard deviations = 8 3 standard deviations = 12 1.5 standard deviations = 6 0.25 ...”
January 28, 2019
GMATGuruNY posted a reply to When 12 marbles are added to a rectangular aquarium, the wat in the Problem Solving forum
“The desired height increase = 11/4 inches. 12 marbles yield a height increase of 3/2 inches. Thus: (desired height increase of 11/4 inches) * (12 marbles)/(height increase of 3/2 inches) = (11/4 * 12)/(3/2) = 33/(3/2) = (33*2)/3 = 11*2 = 22 marbles. The correct answer is D.”
January 28, 2019
GMATGuruNY posted a reply to A certain company has 18 equally qualified applicants for 4 in the Problem Solving forum
“From 18 applicants, the number of ways to choose 4 = 18C4 = (18*17*16*15)/(4*3*2*1) = (3*17*4*15) = 51*60 = 3060. The correct answer is E.”
January 28, 2019
GMATGuruNY posted a reply to A new tower has just been built at the Verbico military in the Problem Solving forum
“Let the PRE-TOWER number of beds = the LCM of the denominators in the problem = 3*5 = 15. Then the CURRENT number of beds = 3*15 = 45, implying that the number of beds in the NEW tower = 45-15 = 30. Occupied beds = (1/3)15 + (1/5)30 = 11. Non-occupied beds in the new tower = 30-11 = 19. ...”
January 28, 2019
Brent@GMATPrepNow posted a reply to A dental licensure exam requires a 75% minimum score in orde in the Data Sufficiency forum
“ Given: A dental licensure exam requires a 75% minimum score in order to pass each section Target question: Did Jennifer pass the 30-question third section? 75% of 30 = 22.5 So, in order to get at least 75% in the 3rd section, Jennifer must correctly answer 23 or more questions in the 3rd ...”
January 28, 2019
GMATGuruNY posted a reply to Machines A and B, working together, take t minutes to in the Problem Solving forum
“One more approach: Since A+B together complete the job in t minutes: Job = (A''s output in t minutes) + (B''s output in t minutes) If A works alone for t minutes, A can then complete the rest of the job in 64 minutes. In this case, the rest of the job = B''s output in t minutes. Thus, A''s ...”
January 27, 2019
Brent@GMATPrepNow posted a reply to Barbara invests $2400 in the National Bank at 5%. How much in the Problem Solving forum
“Barbara invests $2400 in the National Bank at 5%. So, her annual income for this investment = 5% of $2400 = $120 Let x = the additional money Barbara must invest at 8% So, her annual income for this investment = 8% of x = 0.08x So, Barbara''s TOTAL annual income = $120 + 0.08x We want the ...”
January 27, 2019
Brent@GMATPrepNow posted a reply to A certain library assesses fines for overdue books as in the Problem Solving forum
“1st day - $0.10 2nd day - $0.20 or $0.40 (double or add $0.30) $0.20 is the lesser amount 3rd day - $0.40 or $0.50 (double or add $0.30) $0.40 is the lesser amount 4th day - $0.80 or $0.70 (double or add $0.30) $0.70 is the lesser amount The correct answer is B Cheers, Brent”
January 27, 2019
GMATGuruNY posted a reply to Prompted by observations of seemingly related species in the Sentence Correction forum
“A present perfect verb (has + VERBed or have + VERBed) expresses a PAST ACTION that affects the present. Generally, the usage of a present perfect verb implies that the subject of the verb still exists. Incorrect: The dinosaurs have evolved over time. The sentence above is illogical because the ...”
January 27, 2019
GMATGuruNY posted a reply to Machines A and B, working together, take t minutes to in the Problem Solving forum
“Always keep your eye on the answer choices. Since A''s time alone (t+64) is greater than B''s time alone (t+25), the ratio of A''s time alone to B''s time alone must be GREATER THAN 1. Eliminate A, C and D. Since the ratio of A''s time to B''s time = (t+64)/(t+25), option E implies the ...”
January 27, 2019
GMATGuruNY posted a reply to A certain library assesses fines for overdue books as in the Problem Solving forum
“First day: Total fine = 10. For each additional day, the total fine either increases by 30 or doubles -- whichever results in a lesser amount. Second day: Adding 30 cents to the 1-day fine, we get 10+30 = 40. Doubling the 1-day fine, we get 2*10 = 20. Total fine = lesser amount = 20. ...”
January 27, 2019
Brent@GMATPrepNow posted a reply to Probability/ combination in the Problem Solving forum
“P(Tamara and Inga are BOTH chosen for the jury) = (# of ways to choose 7 people that include Tamara and Inga)/(TOTAL # of ways to choose 7 people) # of ways to choose 7 people that include Tamara and Inga Stage 1: place Tamara and Inga on the jury. This can be accomplished in 1 way Stage 2: ...”
January 26, 2019
GMATGuruNY posted a reply to If the drama club and music club are combined, what percent in the Data Sufficiency forum
“Clearly, neither statement alone is sufficient. Statements combined: Case 1: No one is a member of both clubs Total males = 15+10 = 25. Total members = 16+20 = 36. Resulting fraction: (total males)/(total members) = 25/36. Case 2: Every male in the music club is also in the drama ...”
January 26, 2019
GMATGuruNY posted a reply to Frank and Georgia started traveling from A to B at the same in the Problem Solving forum
“Let d = the number of miles between A and B. Since Georgia travels the entire d miles between A and B and then an additional 60 miles back toward A, Georgia''s distance = d+60. Since Frank travels all but 60 of the d miles between A and B, Frank''s distance = d-60. Since Georgia''s travels 3/2 ...”
January 26, 2019
Brent@GMATPrepNow posted a reply to A sports team played 100 games last season. Did this team in the Data Sufficiency forum
“Target question: Did this team win at least half of the games it played last season? Rephrased target question: Did this team win more than 49 games? Statement 1: The team won 60% of its first 65 games In other words, the team won 39 of its first 65 games Since we don''t know the results ...”
January 26, 2019
GMATGuruNY posted a reply to Ratio in the Problem Solving forum
“Let S = the entire season (in other words, the mixture of M and N). Alligation can be performed only with percentages or fractions. Step 1: Convert the ratios to FRACTIONS. M: Since win:losses = 1:2, and 1+2=3, wins/total = 1/3. N: Since wins:losses = 1:3, and 1+3=4, wins/total = 1/4. ...”
January 25, 2019
Brent@GMATPrepNow posted a reply to If 2 roots of the equation x^2+px+q=0 are -3 and 2, what is in the Problem Solving forum
“GIVEN: the roots/solutions are x = -3 and x = 2 Notice that x = -3 and x = 2 are solutions to the equation (x + 3)(x - 2) = 0 If we expand and simplify the left side of the equation, we get: x² + x - 6 = 0 So, the equation x² + x - 6 = 0 has roots -3 and 2 Compare this to x² + px + q = 0 to ...”
January 25, 2019
Brent@GMATPrepNow posted a reply to The numbers m, n, and K are all positive integers. Given tha in the Problem Solving forum
“Different approach: The question asks "which of the following must also be a positive integer factor of K?" So, if we can find an answer choice that is NOT a factor of K we can ELIMINATE that answer choice. A. m + n If K = 12, then if COULD be the case that m = 4 and n = 6 In ...”
January 25, 2019
Brent@GMATPrepNow posted a reply to The numbers m, n, and K are all positive integers. Given tha in the Problem Solving forum
“GIVEN: m is a factor of K This means that we can write: K = md for some integer d If m and d are both integers, then m and d are both factors of K Notice that, if K = md, then d = K/m, which means K/m is a factor of K Answer: D Cheers, Brent”
January 25, 2019
Brent@GMATPrepNow posted a reply to If, J, K, L, M, and N are positive integers in ascending ord in the Data Sufficiency forum
“ Given: J, K, L, M, and N are positive integers in ascending order Target question: What is the value of L? Statement 1: The value of K is 3. There are many scenarios that satisfy statement 1. Here are two: Case a: J = 1, K = 3, L = 4, M = 7, N = 8. In this case, the answer to the ...”
January 25, 2019
GMATGuruNY posted a reply to How many factors greater than 1 do 120, 210, and 270 have in in the Problem Solving forum
“120 = 30*4 210 = 30*7 270 = 30*9 The GCF = the value in blue = 30. Factors of 30 greater than 1: 2, 3, 5, 6, 10, 15, 30 --> 7 factors Thus, 120, 210, and 270 have 7 common factors greater than 1. The correct answer is D.”
January 24, 2019
GMATGuruNY posted a reply to Stacy and Katie plan to walk the 27-mile scenic route across in the Problem Solving forum
“Since Stacy and Katie travel toward each other, they WORK TOGETHER to cover the 27 miles between them. Since Stacy is 1/4 faster than Katie, for every 4 miles that Katie travels, the distance traveled by Stacy = 4 + (1/4)(4) = 5 miles. Thus, of every 9 miles traveled when Stacy and Katie work ...”
January 24, 2019
Brent@GMATPrepNow posted a reply to Mary and Kate are running clockwise around a circular track in the Problem Solving forum
“To get a better idea of what''s happening, let''s sketch the set-up: https://i.imgur.com/SwHzFJD.png Mary is faster than Kate, we can say that Kate has a 250 meter head start. In other words, when Mary closes that 250-meter gap, she will pass Kate for the FIRST time. ...”
January 24, 2019
Brent@GMATPrepNow posted a reply to In the rectangular coordinate system above, the area of tria in the Problem Solving forum
“Let''s draw a rectangle around the triangle (as shown below) and then subtract from the rectangle''s area (28) the areas of the 3 right triangles that surround the triangle in question. We get the following: http://s13.postimage.org/a47qx0j8j/triangle_in_coordinate_plane_2.jpg So, the area ...”
January 24, 2019
Brent@GMATPrepNow posted a reply to A shirt that costs k dollars is increased by 30%, then by an in the Problem Solving forum
“A shirt that costs k dollars is increased by 30%, So, the new coast = k + (30% of k) = k + 0.3k = 1.3k ASIDE So, increasing a value by 30% is the same as multiplying that value by 1.3 Similarly, increasing a value by 20% is the same as multiplying that value by 1.2 And increasing a value by ...”
January 24, 2019
Brent@GMATPrepNow posted a reply to The total cost of a vacation was divided among 3 people. If in the Problem Solving forum
“Let T = total cost of vacation So, T/3 = cost per person with THREE people And T/4 = cost per person with FOUR people If the total cost of the vacation had been divided equally among 4 people, the cost per person would have been $50 less. In other words (cost per person with FOUR people) = ...”
January 24, 2019
Brent@GMATPrepNow posted a reply to A restaurant meal cost $35.50 and there was no tax. If the t in the Problem Solving forum
“Let''s first see what happens when the tip is 10% 10% of $35.50 = $3.55 So, the total cost (WITH a 10% tip) = $35.50 + $3.55 = $39.05 So, the total cost must be GREATER THAN $39.05 This means the TOTAL cost could be $39.06 Check the answer choices.... A, D and E do not allow for the total cost ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to If i, a and b are integers, is 4(3b + 2) = 5a? (1) If i is in the Data Sufficiency forum
“Target question: Is 4(3b + 2) = 5a? Statement 1: If i is divided by 5 the quotient is a and the remainder is 3 ASIDE: There''s a nice rule that says, "If N divided by D equals Q with remainder R, then N = DQ + R" For example, since 17 divided by 5 equals 3 with remainder 2, then we ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to If the average of four numbers is 35, how many of the number in the Data Sufficiency forum
“ Given: The average of four numbers is 35 Target question: How many of the numbers are less than 35? If we''re able to see that the statements FEEL insufficient, and we''re able to come up with some counter-examples in our head, then we can head straight to... . . . Statements 1 and 2 ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to If x is a positive integer, is x<16? 1) x is less than t in the Data Sufficiency forum
“Target question: Is x < 16? Statement 1: x is less than the average (arithmetic mean) of the first ten positive integers Since the first ten positive integers are EQUALLY SPACED, the average = (smallest number + biggest number)/2 = (1 + 10)/2 = 5.5 So, x < 5.5 Since 5.5 < 16, we ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to What is the measure of each interior angle of a regular deca in the Problem Solving forum
“Useful rule: the sum of the angles in an n-sided polygon = (n - 2)(180º) So, for example, the sum of the angles in an 11-sided polygon = (11 - 2)(180º) = (9)(180º) = 1620º What is the measure of each interior angle of a regular decagon? A decagon has 10 sides. The sum of the angles in ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to x=? in the Data Sufficiency forum
“Target question: What is the value of x? Statement 1: x³ - x = 0 Factor to get: x(x² - 1) = 0 Factor again to get: x(x + 1)(x - 1) = 0 So, it could be the case that x = 0, x = -1 or x = 1 Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to Ayayai electronics is a company manufacturing MP3 players. in the Problem Solving forum
“I thought I''d point out that Jay''s approach is known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of MP3 players, and the two characteristics are: ...”
January 23, 2019
Brent@GMATPrepNow posted a reply to If when a certain integer x is divided by 5, the remainder in the Problem Solving forum
“Here''s another (longer) approach: When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k ...”
January 22, 2019
Brent@GMATPrepNow posted a reply to If Polygon X has fewer than 9 sides, how many sides does in the Data Sufficiency forum
“Target question: How many sides does Polygon X have? Given: Polygon X has fewer than 9 sides Useful rule: The sum of the angles in an n-sided polygon = (n - 2)(180º) Since the polygon has FEWER than 9 sides, there are are exactly SIX possible cases: case a: There are 8 sides, in ...”
January 22, 2019
GMATGuruNY posted a reply to If when a certain integer x is divided by 5, the remainder in the Problem Solving forum
“Since dividing x by 5 yields a remainder, x is not a multiple of 5 and thus not a multiple of 10. Since x is not a multiple of 10, x/10 cannot yield an integer value. The correct answer is B.”
January 22, 2019
GMATGuruNY posted a reply to Mary and Kate are running clockwise around a circular track in the Problem Solving forum
“Since Mary is behind Kate by 250 meters -- half the circumference of the track -- she will catch up to Mary when she has traveled 250 meters more than Kate. To catch up to Kate a second time, Mary must then travel one more lap than Kate -- in other words, 500 meters more than Kate. Implication: ...”
January 22, 2019
Brent@GMATPrepNow posted a reply to The number 75 can be written as the sum of the squares of 3 in the Problem Solving forum
“We''re looking for 3 DIFFERENT squares that add to 75 Here are the only squares we need to consider: 1, 4, 9, 16, 25, 36, 49, 64 Can you find 3 that add to 75? After some fiddling, we may notice that 1 + 25 + 49 In other words, 1² + 5² + 7² = 75 We want the SUM of 1 + 5 + 7, which is ...”
January 22, 2019
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Data Sufficiency Video #2: The Elimination Method Video: https://www.youtube.com/watch?v=amhxP9My_pU Cheers, Brent”
January 22, 2019
GMATGuruNY posted a reply to If y=|x-1|+|x+1|, then y=? in the Data Sufficiency forum
“|x-1| = the distance between x and 1. |x+1| = the distance between x and -1. -1<--|x+1|-->x<--|x-1|-->1 Here, since the total distance between the two endpoints is 2, the sum of the 2 distances in red is 2. If x is any value between the two endpoints, then the sum of the two ...”
January 22, 2019
GMATGuruNY posted a reply to A = (2-3+4)^{11}, and B = (-2+3-4)^{11}. What is the value o in the Problem Solving forum
“A = (2-3+4)¹¹ = 3¹¹ B = (-2+3-4)¹¹ = (-3)¹¹ = -3¹¹ Thus: A+B = 3¹¹ - 3¹¹ = 0 2^(A+B) = 2⁰ = 1. The correct answer is C.”
January 22, 2019
GMATGuruNY posted a reply to GMAT OG 2019 The Commerce Department reported that in the Sentence Correction forum
“were + VERBing is the plural form of the PAST PROGRESSIVE tense (also known as the past continuous tense). The past progressive tenses serve to express actions that happen CONTINUOUSLY FOR A LIMITED DURATION OF TIME. OA: While businesses were expanding their production, unsold goods were piling ...”
January 22, 2019
GMATGuruNY posted a reply to Machine A produces pencils at a constant rate of 9000 in the Problem Solving forum
“To minimize B''s time, we must maximize A''s time. Since each machine can work for at most 8 hours, let A''s time = 8 hours. Since A''s rate = 9000 pencils per hour, the number of pencils produced by A in 8 hours = rt = 9000*8 = 72,000. Remaining pencils = 100,000 - 72,000, = 28,000. Since ...”
January 21, 2019
Brent@GMATPrepNow posted a reply to The average salary of 15 people in the shipping department in the Problem Solving forum
“]The average salary of 15 people in the shipping department at a certain firm is $20,000 So, (sum of all 15 salaries)/15 = $20,000 Multiply both sides by 15 to get: sum of all 15 salaries = $300,000 The salary of 5 of the employees is $25,000 each and the salary of 4 of the employees is $16,000 ...”
January 21, 2019
ceilidh.erickson posted a reply to In the figure above, segments PQ and QR are each parallel to in the Data Sufficiency forum
“It is generally true in Data Sufficiency that if the question asks you for a PROPORTION, you do not need concrete values to answer it. In this case, we''re asked for a RATIO of horizontal and vertical lengths, but not for actual values. We can think of any slope as a RATIO of vertical to ...”
January 21, 2019
ceilidh.erickson posted a reply to At a certain fruit stand, the price of each apple is 40 cent in the Problem Solving forum
“We can also think of this as a WEIGHTED AVERAGE question. If we buy some 40 cent apples and 60 cent oranges, the average price for all fruit will be between 40 and 60. If we buy more apples, it''ll be closer to 40. If more oranges, it''ll be closer to 60. --|--------------|----| ...”
January 21, 2019
ceilidh.erickson posted a reply to Journalist: Every election year at this time the state gover in the Critical Reasoning forum
“For more on using this strategy for BOLDFACE questions on CR, see: https://www.beatthegmat.com/most-of-western-music-since-the-renaissance-has-been-based-t305309.html#823603 https://www.beatthegmat.com/gmat-official-guide-2019-in-countries-where-automobile-t303686.html#818265 ...”
January 21, 2019
ceilidh.erickson posted a reply to What is the average (arithmetic mean) of x, y, and z? in the GMAT Math forum
“You should always start by REPHRASING any DS question to determine: what''s the minimum information that would be sufficient to answer this question? Our question is "what is the average of x, y, and z?" First, rephrase algebraically: (x + y + z)/3 = ? What would we need in order ...”
January 21, 2019
ceilidh.erickson posted a reply to Journalist: Every election year at this time the state gover in the Critical Reasoning forum
“The goal in any BOLDFACE question is to deconstruct the argument, and determine the role of each statement: - author''s conclusion / position - reasoning that supports the author''s position - the counterpoint / what others believe - support for the counterpoint - neutral / background ...”
January 21, 2019
ceilidh.erickson posted a reply to As even most smokers will admit, smoking is both unhealthy a in the Sentence Correction forum
“This two-part parallelism - also known as CLOSED PARALLELISM - is very common on the GMAT. Any time you see the following: BOTH ____ AND ____ EITHER ____ OR ______ NOT ONLY _____BUT ALSO _______ NOT ________ BUT _________ etc, ... you need to make sure that what comes right after the ...”
January 21, 2019
GMATGuruNY posted a reply to A bowl contains pecans, cashews, and almonds in a ratio of 6 in the Problem Solving forum
“Original ratio values: P.................................................C...............................................A 6x<---distance of 4x--->10x<---distance of 5x--->15x Options for the new ratio: I) 1 : 2 : 3 I) 2 : 3 : 4 III) 4 : 7 : 10 The ratio values in each ...”
January 21, 2019
ceilidh.erickson posted a reply to As even most smokers will admit, smoking is both unhealthy a in the Sentence Correction forum
“This question is testing PARALLELISM and SUBJECT/VERB agreement. When there is a closed parallel marker such as BOTH X AND Y, the part of the sentence that follows "both" must be parallel to the part that follows "and." In each of the answer choices, I''ve highlighted what ...”
January 21, 2019
Brent@GMATPrepNow posted a reply to A triangle has side lengths of a, b, and c centimeters. in the GMAT Math forum
“Target question: Does each angle in the triangle measure less than 90 degrees? Given: A triangle has side lengths of a, b, and c centimeters Statement 1: The 3 semicircles whose diameters are the sides of the triangle have areas that are equal to 3 cm², 4 cm², and 6 cm², respectively. ...”
January 21, 2019
ceilidh.erickson posted a reply to The senate candidate expressed outrage that few judges have in the Critical Reasoning forum
“This is NOT a Manhattan Prep question. It is not even a GMAT-style question; it is an LSAT-style question. Students should disregard this question. The poster should also take care to only cite sources if he/she got the problem directly from the source. This problem seems to have been taken from ...”
January 21, 2019
Brent@GMATPrepNow posted a reply to If x-2y=4, then x^2-4xy+4y^2-x+2y=? in the Problem Solving forum
“GIVEN: x - 2y = 4 We want to find the value of x² - 4xy + 4y² - x + 2y We should notice that x² - 4xy + 4y² is equal to (x - 2y)² We should notice that - x + 2y is equal to -(x - 2y) We get: x² - 4xy + 4y² - x + 2y = (x - 2y)² - (x - 2y) Now replace x - 2y with 4 to get: = (x - ...”
January 21, 2019
Brent@GMATPrepNow posted a reply to What is the value of z in the triangle above? (1) x+y=139 ( in the Data Sufficiency forum
“Target question: What is the value of z in the triangle above? IMPORTANT: Since angles in a triangle must add to 180 degrees, we can write: x + y + z = 180 Statement 1: x + y = 139 Take: x + y + z = 180 and replace (x + y) with 139 to get: 139 + z = 180 Solve equation for z to get: z = 41 ...”
January 21, 2019
Brent@GMATPrepNow posted a reply to 10 different biology books and 8 different chemistry books l in the Problem Solving forum
“Take the task of selecting 4 books and break it into stages. Stage 1: Select two biology books Since the order in which we select the books does not matter, we can use combinations. We can select 2 books from 10 books in 10C2 ways (45 ways) So, we can complete stage 1 in 45 ways If ...”
January 21, 2019
Brent@GMATPrepNow posted a reply to What was the number of defective batteries in a shipment of in the Data Sufficiency forum
“Target question: What was the number of defective batteries in a shipment of 4000 batteries? Statement 1: In a particular sample of 10 batteries selected from the shipment, 1 was defective. Don''t make the mistake of assuming that this means 1/10 of ALL batteries are defective. There''s no ...”
January 21, 2019
GMATGuruNY posted a reply to If x-2y=4, then x^2-4xy+4y^2-x+2y=? in the Problem Solving forum
“Let x=4 and y=0, with the result that x-2y = 4. Plugging x=4 and y=0 into x² - 4xy + 4y² - x + 2y, we get: 4² - 0 + 0 - 4 + 0 = 12. The correct answer is A.”
January 21, 2019
Brent@GMATPrepNow posted a reply to On a game show, a contestant is given three keys, each of in the Problem Solving forum
“There aren''t many possible outcomes, so let''s start by listing all possibilities. Let A, B and C represent the 3 boxes, and let a, b, c, be the keys for those boxes (in that same order). A = $1 prize, B = $100 prize and C = $1000 prize If the boxes are arranged as A-B-C, then these are ...”
January 20, 2019
Brent@GMATPrepNow posted a reply to Which of the following lists a number of points at which a in the Problem Solving forum
“http://s27.postimg.cc/531tmnqpr/circ_int.jpg Answer: E The important takeaway here is that "intersect" does not necessarily mean "pass through" So, a line that is tangent to a circle (touching the circle but not passing through it) can be said to intersect the circle. To ...”
January 20, 2019
Brent@GMATPrepNow posted a reply to [x] denotes the least integer greater than or equal to x ... in the Problem Solving forum
“First, let''s take a moment to get a good idea of what this strange notation means. A few examples: -1 < x/2 ≤ 0 Multiply all sides of the inequality by 2 to get: -2 < x ≤ 0 Check the answer choices.... Only -3/2 falls inside that range. Answer: B Cheers, Brent”
January 20, 2019
Brent@GMATPrepNow posted a reply to Full Plan in the The 60-Day GMAT Study Guide forum
“Hi Aliya, I have a feeling that your email system is treating the emails as spam. Have you checked your spam/junk folders? You might to sign up for the emails again, but this time, be sure to add guide@beatthegmat.com as a contact in your e-mail system. This will help ensure that the daily ...”
January 20, 2019
Brent@GMATPrepNow posted a reply to The average American spends y dollars on food per month, exc in the Problem Solving forum
“This is a Variables in the Answer Choices question (VIAC). This question type can be answered algebraically or using the INPUT-OUTPUT approach. Mitch has demonstrated the INPUT-OUTPUT approach, so let''s solve the question algebraically. The average American spends y dollars on food per month, ...”
January 20, 2019
GMATGuruNY posted a reply to A company bought some desks at a price of $150 each and some in the Data Sufficiency forum
“Test the THRESHOLD. In the question stem, the threshold is 40 CHAIRS. The total cost of 40 chairs = 40*50 = 2000. Statement 1: The total price of the desks and chairs is 5,000. It is possible that 40 chairs are purchased (at a total cost of $2000) or that MORE CHAIRS are purchased. ...”
January 20, 2019
GMATGuruNY posted a reply to What is the value of x? in the Data Sufficiency forum
“Statement 1: To have exactly 3 positive factors, x must be the square of a prime number. Factors of x=2²=4: 1, 2, 4 Factors of x=3²=9: 1, 3, 9 Factors of x=5²=25: 1, 5, 25. Since x can be different values, INSUFFICIENT. Statement 2: Clearly INSUFFICIENT. Statements combined: x ...”
January 20, 2019
GMATGuruNY posted a reply to The average American spends y dollars on food per month, exc in the Problem Solving forum
“Monthly food expense except in January: Let y=$2. Discount in January: Let x=100%. Since $2 is spent each month for 8 of the first 9 months, the total spent during these 8 months = 8*2 = 16. Since food purchases are 100% lower in January -- implying that they are FREE in January -- the amount ...”
January 20, 2019
Brent@GMATPrepNow posted a reply to If a is a positive integer and 81 divided by a in the Data Sufficiency forum
“Target question: What is the value of a? Given: 81 divided by a results in a remainder of 1 In other words, 81 is 1 greater than some multiple of a This means that 80 is some multiple of a Another way to say this is: a is a divisor of 80 The divisors of 80 are: 1, 2, 4, 5, 8, 10, 16, ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to Set A = {2, 3, 4, 5}, and set B = {4, 5, 6, 7, 8}. If P = th in the Problem Solving forum
“Let''s list and count all possible outcomes. Possible products when 2 is selected from set A: 8, 10, 12, 14, 16 Possible products when 3 is selected from set A: 12, 15, 18, 21, 24 Possible products when 4 is selected from set A: 16, 20, 24, 28, 32 Possible products when 5 is selected from set ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to If Sam were twice as old as he is, he would be 40 years in the Problem Solving forum
“Jim is 10 years younger than Sam Let x = Sam''s PRESENT age So, x - 10 = Jim''s PRESENT age If Sam were twice as old as he is, he would be 40 years older than Jim. TWICE Sam''s age = 2x So, we can write: 2x = (x - 10) + 40 Simplify: 2x = x + 30 Solve: x = 30 Answer: B Cheers, Brent”
January 19, 2019
Brent@GMATPrepNow posted a reply to One night a certain hotel rented 3/4 of its rooms, including in the Problem Solving forum
“This question is a great candidate for the Double Matrix method, whichcan be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of motel rooms, and the two characteristics are: - air conditioning or no air ...”
January 19, 2019
GMATGuruNY posted a reply to In a certain pet shop, 1/3 of the pets are dogs and 1/5 of in the Data Sufficiency forum
“Alternate approach: To determine the ratio of birds to dogs, plug in a TEST VALUE for the total number of pets. Let b = the number of birds and d = the number of dogs. Let the test value for the total number of pets = the LCM of 3 and 5 = 15. Since 1/5 are birds, b = 1/5 * 15 = 3. Since 1/3 ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to In a certain pet shop, 1/3 of the pets are dogs and 1/5 of in the Data Sufficiency forum
“Target question: How many of the pets are dogs? Given: 1/3 of pets are dogs & 1/5 of pets are birds Let T = TOTAL number of pets. So, T/3 = number of dogs And T/5 = number of birds Statement 1: There are 30 birds at the pet shop So, T/5 = 30 This means that T = 150, which ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to Is x > y? (1) -4x + 2y < y - 3x (2) wx > wy in the Data Sufficiency forum
“Target question: Is x > y? Statement 1: -4x + 2y < y - 3x Add 4x to both sides to get: 2y < y + x Subtract y from both sides to get: y < x Perfect, the answer to the target question is YES, x IS greater than y Since we can answer the target question with certainty, statement 1 ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to At a certain fruit stand, the price of each apple is 40 cent in the Problem Solving forum
“It turns out that the cost per apple is irrelevant. Here''s why: The average (arithmetic mean) price of the 10 pieces of fruit is 56 cents So, (total value of all 10 pieces of fruit)/10 = 56 cents This means, total value of all 10 pieces of fruit = 560 cents How many oranges must Mary put ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to A set consists of 5 distinct positive integers a, b, c, d, e in the Problem Solving forum
“The mean of all 5 numbers is 8.8 (a + b + c + d + e)/5 = 8.8 Multiply both sides by 5 to get: a + b + c + d + e = 44 The sum of a, c and e is 24 (a + c + e) = 24 So, take a + b + c + d + e = 44 and rewrite as: (a + c + e) + b + d = 44 We get: (24) + b + d = 44 So, b + d = 20 b is the ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to If x and y are consecutive integers such that x < y and x in the GMAT Math forum
“Oops - pressed the wrong button. As you were! Brent”
January 19, 2019
Brent@GMATPrepNow posted a reply to If 3 years ago Jennifer was 22 years old, how old is Carmen in the Data Sufficiency forum
“Target question: How old is Carmen now? Given: 3 years ago Jennifer was 22 years old So, Jennifer''s PRESENT age is 25 Statement 1: 10 years ago, Carmen was twice as old as Jennifer. If Jennifer''s PRESENT age is 25, then Jennifer''s age 10 YEARS AGO was 15 This means Carmen''s age 10 ...”
January 19, 2019
Brent@GMATPrepNow posted a reply to In a barrel full of apples, 45% of the apples weigh more in the Problem Solving forum
“No takers? Let''s say there are 100 apples in the barrel. 45% of the apples weigh MORE THAN 81 grams This means 55% of the apples weigh LESS THAN OR EQUAL to 81 grams In other words, 55 apples weigh LESS THAN OR EQUAL to 81 grams 81% of the apples weigh LESS THAN 145 grams This means 19% ...”
January 18, 2019
GMATGuruNY posted a reply to How many hours did it take Helen to drive from her house to in the Data Sufficiency forum
“Statement 1: If d=72, then t = d/r = 72/72 = 1 hour. If d=144, then t = 144/72 = 2 hours. Since the time can be different values, INSUFFICIENT. Statement 2: Time and rate have a RECIPROCAL RELATIONSHIP: If the time is cut in HALF, then the rate DOUBLES. If the time DOUBLES, then the ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to Passing the 30-question third section in the Data Sufficiency forum
“ Given: A dental licensure exam requires a 75% minimum score in order to pass each section Target question: Did Jennifer pass the 30-question third section? 75% of 30 = 22.5 So, in order to get at least 75% in the 3rd section, Jennifer must correctly answer 23 or more questions in the 3rd ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to 32 teams compete in the World Cup of Soccer. They are divid in the Problem Solving forum
“Perfect approach! ASIDE: We have 4 teams, and 2 teams play a game. So, the number of games played = the number of different ways to select 2 of the 4 teams = 4C2 = 6 Cheers, Brent”
January 18, 2019
Brent@GMATPrepNow posted a reply to Does (a – 2)(b + 4) = 8? in the GMAT Math forum
“Target question: Does (a – 2)(b + 4) = 8? This is a good candidate for rephrasing the target question. When I SCAN the statements, I see that statement 1 has the term ab. This suggests to me that we might benefit from EXPANDING the expression, since that will result in an ab term. Take: (a ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to A fair die has sides labeled with 1, 2, 3, 4, 5, and 6 dots. in the GMAT Math forum
“We want P(select at least one 6) When it comes to probability questions involving "at least," it''s best to try using the complement. That is, P(Event A happening) = 1 - P(Event A not happening) So, here we get: P(getting at least one 6) = 1 - P(not getting at least one 6) What does ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to If x and y are consecutive integers such that x < y and x in the GMAT Math forum
“GIVEN: x and y are consecutive integers such that x < y So, if x is ODD, then y is EVEN One option here is to replace the x''s and y''s with ODD and EVEN and apply the rules for ODDs and EVENs. Or we can just replace x and y with odd and even numbers. Let''s do that. Replace x with 1 ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to is x > 0? in the GMAT Math forum
“Target question: Is x > 0 ? Statement 1: x – y > –8 This statement doesn''t feel sufficient, so I''ll TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = 0. In this case, the answer to the target question is YES, x ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to If x is an integer greater than 2, the function f(x) in the GMAT Math forum
“The key here is that f(51) is EQUAL to f(50) Here''s why: According to the definition of the function f, f(51) = (2)(4)(6). . . (48)(50), and f(50) = (2)(4)(6). . . (48)(50) So, f(51) - f(50) = (2)(4)(6). . . (48)(50) - (2)(4)(6). . . (48)(50) = 0 Answer: E Cheers, Brent”
January 18, 2019
GMATGuruNY posted a reply to If tank X contains only gasoline, how many kiloliters of gas in the Data Sufficiency forum
“Let G = the gas in the tank and C = the capacity of the tank. Statement 1: G - (1/2)G = (1/3)C No way to solve for G. INSUFFICENT. Statement 2: G + 0.75 = C No way to solve for G. INSUFFICIENT. Statements combined: Since we have two variables (G and C) and two distinct linear ...”
January 18, 2019
Brent@GMATPrepNow posted a reply to What percentage of his bills did Stanley pay before their in the Data Sufficiency forum
“Target question: What percentage of his bills did Stanley pay before their due dates last month? This is a great candidate for rephrasing the target question. Aside: We have a free video with tips on rephrasing the target question: Let P = # of bills PAID before due date Let T = TOTAL # of ...”
January 17, 2019
Brent@GMATPrepNow posted a reply to Overlapping figures in the Problem Solving forum
“If the area of the square is 4, then each side has length 2 https://i.imgur.com/Ul16WsZ.png At this point, we have a special 30-60-90 right triangle. When we compare this blue triangle to the BASE 30-60-90 right triangle . . . https://i.imgur.com/vrYSacE.png . . . we see that the blue ...”
January 17, 2019
GMATGuruNY posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“Here, the value in red is the sum of Jake''s weight and TWICE the sister''s weight: 187 + 2(89.5) = 366. But the prompt gives an integer value for the sum of Jake''s weight and the sister''s ACTUAL weight -- a constraint that forces Jake''s weight to be an even integer.”
January 17, 2019
GMATGuruNY posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“The sum of Jake''s weight and his sister''s weight is an INTEGER VALUE. The answer choices indicate that Jake''s weight is an INTEGER VALUE. Implication: The sister''s weight must also be an integer value. Thus, the value in red -- 89.5 -- is not a valid option for the sister''s weight. Given ...”
January 17, 2019
Brent@GMATPrepNow posted a new topic called Set A = {2, 3, 4, 5}, and set B = {4, 5, 6, 7, 8}. If P = th in the Problem Solving forum
“Set A = {2, 3, 4, 5}, and set B = {4, 5, 6, 7, 8}. If P = the product of one number chosen from set A and one number chosen from set B, how many DIFFERENT values of P are possible? A) 14 B) 15 C) 16 D) 18 E) 20 Answer: C Difficulty level: 600 - 650 Source: www.gmatprepnow.com”
January 17, 2019
Brent@GMATPrepNow posted a reply to If 20 Swiss Francs is enough to buy 9 notebooks in the Data Sufficiency forum
“Target question: Is 40 Swiss Francs enough to buy 12 notebooks and 12 pencils? This is a great candidate for rephrasing the target question. Let N = the cost of 1 notebook (in Swiss francs) Let P = the cost of 1 pencil (in Swiss francs) So, 12 notebooks cost 12N and 12 pencils cost 12P ...”
January 17, 2019
GMATGuruNY posted a reply to The speed of a boat is 5 times the speed at which a river fl in the Problem Solving forum
“Let the river''s rate = 1 mph and the boat''s rate = 5 mph. When the boat travels DOWNRIVER, the boat and the river WORK TOGETHER, so we ADD their rates: 5+1 = 6 mph. When the boat travels UPRIVER, the boat and the river COMPETE, so we SUBTRACT their rates: 5-1 = 4 mph. Rate and time have ...”
January 17, 2019
GMATGuruNY posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“ALWAYS KEEP YOUR EYE ON THE ANSWER CHOICES. If Jake loses 8 pounds, he will weigh twice as much as his sister. j-8 = 2s j = 2s + 8 = even + even = even. Since Jake''s weight must be an EVEN VALUE, the correct answer is E.”
January 17, 2019
Brent@GMATPrepNow posted a reply to The speed of a boat is 5 times the speed at which a river fl in the Problem Solving forum
“Let x = the speed of the river (in miles per hour) So, 5x = the speed of the boat in (miles per hour) Let d = distance traveled (in miles) This means the boat''s speed going UPriver = 5x - x = 4x And the boat''s speed going DOWNriver = x + 5x = 6x time = distance/speed So, travel time ...”
January 17, 2019
Brent@GMATPrepNow posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“Here''s a solution that uses one variable. Let x = Jake''s present weight in pounds So, x - 8 = Jake''s hypothetical weight IF he were to lose 8 pounds If Jake loses 8 pounds, he will weigh twice as much as his sister. In other words, the sister weighs HALF as much as Jake''s hypothetical ...”
January 17, 2019
Brent@GMATPrepNow posted a reply to Three children, John, Paul, and Ringo, are playing a game. in the Problem Solving forum
“The main concept here is that all 3 children are equally likely to win this game (unless one of them possesses supernatural powers that allow him to know what numbers the other two boys will choose :-)) Also note that, if everything is random, the probability of winning by choosing the number 2 ...”
January 16, 2019
Brent@GMATPrepNow posted a new topic called In a barrel full of apples, 45% of the apples weigh more in the Problem Solving forum
“In a barrel full of apples, 45% of the apples weigh more than 81 grams, and 81% of the apples weigh less than 145 grams. What percent of the apples in the barrel weigh more than 81 grams but less than 145 grams? A) 16 B) 18 C) 26 D) 32 E) 36 Answer: C Difficulty level: 600 - 650 Source: ...”
January 16, 2019
Brent@GMATPrepNow posted a reply to What is the surface area of the solid right circular in the Problem Solving forum
“Given: radius = 3 Height = 10 Surface area of cylinder = 2πr² + 2πrh = 2π(3²) + 2π(3)(10) = 18π + 60π = 78π Answer: D Cheers, Brent”
January 16, 2019
Brent@GMATPrepNow posted a reply to Three children, John, Paul, and Ringo, are playing a game. in the Problem Solving forum
“This is one of my all-time favorite questions!! The main concept here is that all 3 children are equally likely to win this game (unless one of them possesses supernatural powers that allow him to know what numbers the other two boys will choose :-)) Also note that, if everything is random, ...”
January 16, 2019
GMATGuruNY posted a reply to Sarah is in a room with 6 other children. If the other child in the Data Sufficiency forum
“Let S = Sara''s age. Sum of the ages = 2+4+5+8+10+13+S = 42+S. Statement 1: Since the average age is equal to an INTEGER -- the fourth largest age -- we get: Sum of the ages = (number of ages)(average age) = (7)(INTEGER) = multiple of 7. The blue expression and the red expression each ...”
January 16, 2019
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 From 2000 to 2003, the number in the Problem Solving forum
“From 2000 to 2003, the number of employees at a certain company increased by a factor of 1/4 Let x = the number of employees in 2000 So, the number of employees in 2003 = x + (1/4)x = (5/4)x From 2003 to 2006, the number of employees at this company decreased by a factor of 1/3 (5/4)x = the ...”
January 16, 2019
Brent@GMATPrepNow posted a reply to The usual price of a bagel was reduced during a sale. How mu in the Data Sufficiency forum
“Target question: How much money could be saved by purchasing 10 bagels at the sale price rather than at the usual price? Statement 1: The usual price for a bagel is $0.50 per bagel. Since there''s no information about the SALE price, there''s no way to calculate the amount saved. Since we ...”
January 16, 2019
GMATGuruNY posted a reply to If the median and the range of the data set 1, 1, 2, 2, 3, 3 in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of m. When the correct answer is plugged in, the median will be equal to the range. Note: When the prompt includes the phrase which of the following, the correct answer is likely to be D or E. E: m=3 Resulting set: 1, 1, 2, 2, m=3, 3, 3, ...”
January 16, 2019
GMATGuruNY posted a reply to Henry eats X scones in X percent of the time it takes Rachel in the Problem Solving forum
“Let X=8 and Y=4. Henry eats X scones in X percent of the time it takes Rachel to eat Y scones. Since Henry eats X=8 scones in 8% of the time it takes Rachel to eat Y=4 scones -- 10 minutes, according to the prompt -- the time for Henry to eat 8 scones = 8% of 10 minutes = (8/100)(10) = 4/5 ...”
January 15, 2019
Brent@GMATPrepNow posted a reply to Henry eats X scones in X percent of the time it takes Rachel in the Problem Solving forum
“Let''s use the INPUT-OUTPUT approach. Let''s assign some values of X and Y so that they satisfy the information in the question. Let X = 25. This means Henry eats 25 scones in 25 percent of the time it takes Rachel to eat Y scones Let Y = 100. This means Henry eats 25 scones in 25 percent of ...”
January 15, 2019
Brent@GMATPrepNow posted a reply to Roger wants to arrange three of his five books on his in the Problem Solving forum
“I''m not crazy about this question. The official answer suggests that, although 2 books are DUPLICATES, they''re still considered DIFFERENT. Here''s what I mean: Let''s let D and d represent the two duplicate books. Let, A, B and C represent the other three books. The official answer ...”
January 15, 2019
Brent@GMATPrepNow posted a reply to The three-digit positive integer n can be written as ABC, in in the Data Sufficiency forum
“IMPORTANT point: The VALUE of a 3-digit integer xyz is 100x + 10y + z Example: 723 = (7)(100) + (2)(10) + 3 Target question: What is the remainder when n is divided by 37? Statement 1: A + B/10 + C/100 = B + C/10 + A/100 Multiply both sides by 100 to get: 100A + 10B + C = 100B + 10C + ...”
January 15, 2019
ceilidh.erickson posted a reply to GMATPaper : As measured by the Commerce in the Sentence Correction forum
“Hm, I''m inclined to think that the sentence would NOT work as you suggested: ... corporate profits peaked in the fourth quarter of 1988 but they have slipped since then The word "peaked" already implies that it was a high point, naturally followed by lower values. The contrast word ...”
January 15, 2019
ceilidh.erickson posted a reply to At the end of the first quarter, the share price of a in the Problem Solving forum
“Calculating the correct answer isn''t difficult, as Brent demonstrated. However, savvy GMAT test takers will always try to use logic to eliminate answer choices before they even start calculating! The student who isn''t reading carefully might think "up 20%... then up 50%... that''s a ...”
January 15, 2019
ceilidh.erickson posted a reply to In a certain bathtub, both the hot and cold water fixtures in the Problem Solving forum
“We can easily use logic to get the correct answer, without doing any calculations. In WORK rate problems, when two machines / faucets / people, etc, work together, a) they work at the SUM of their respective rates, and b) the time that it takes them to complete the task together is LESS than ...”
January 15, 2019
ceilidh.erickson posted a reply to Every day in the morning Ross cycles for 2 hours. He always in the Problem Solving forum
“You could also avoid calculation and easily estimate your way to the correct answer to save time on this problem. As Mitch demonstrated, 1 mile per 12 min --> 5 miles per hr for the first part of the trip. If Ross rides at half the speed for the return trip, then the overall average speed ...”
January 15, 2019
ceilidh.erickson posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum
“OP, are you sure this is an OG question? Which edition of the OG did you get this problem from? It''s not in any edition I own. A google search yields only 1 post from gmatclub, and 3 posts on this forum - all posted by you in the last month. The wording of this problem does not sound like an OG ...”
January 15, 2019
Brent@GMATPrepNow posted a reply to If x, y are integers, is x^2+x+y an odd integer? in the Data Sufficiency forum
“ Given: x and y are integers Target question: Is x² + x + y an odd integer? This is a good candidate for rephrasing the target question. Take x² + x + y and factor the first two terms to get: x(x + 1) + y Notice that x and x+1 are CONSECUTIVE INTEGERS, which means one value is ODD and ...”
January 15, 2019
GMATGuruNY posted a reply to A rectangular wall has dimensions of 800 by 300. If the wall in the Problem Solving forum
“number of tiles = (wall area)/(tile area) = (800*300)/(25*12) = 32*25 = 800. The correct answer is E.”
January 15, 2019
GMATGuruNY posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum
“Consider the following equation: 7x + 5y = 70. If x and y are nonnegative integers, the following solutions are possible: x=10, y=0 x=5, y=7 x=0, y=14. Notice the following: The value of x changes in increments of 5 (the coefficient for y). The value of y changes in increments of ...”
January 15, 2019
Brent@GMATPrepNow posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum
“In order to minimize the number of homeowners, we must MAXIMIZE the number of men in the group, since the proportion of male homeowners (20%) is less than the proportion of female homeowners (25%) So, let''s see what happens if there are 199 men and 1 woman. If 20% (aka 1/5) of the men are ...”
January 15, 2019
GMATGuruNY posted a reply to The cost of a square slab is proportional to its thickness a in the Data Sufficiency forum
“x is directly proportional to y implies the following: x/y = k. x = ky. In each case, k is a CONSTANT. The cost of a square slab is proportional to its thickness and also proportional to the square of its length. Thus: c = k * T * L². What is the cost of a square slab that is 3 meters ...”
January 15, 2019
GMATGuruNY posted a reply to Thomasville tree planting in the Critical Reasoning forum
“species may be singular or plural. Passage: Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now. Here, the verb attributed to species is turns. Since turns is singular, ...”
January 14, 2019
Brent@GMATPrepNow posted a reply to Three machines have equal constant work rates. It takes h + in the Problem Solving forum
“ It takes h + 3 hours to produce 360 toys when 2 machines work together So, during those h + 3 hours, EACH machine makes 180 toys So, ONE machine can produce 180 toys in h + 3 hours rate = output/time So, we can write: rate of ONE machine = 180/(h + 3) It takes h hours to produce 360 toys ...”
January 14, 2019
GMATGuruNY posted a reply to Three machines have equal constant work rates. It takes h + in the Problem Solving forum
“(number of machines)(number of hours) = number of toys that are produced. In the prompt above, the blue values are THE SAME. Implication: 2 machines take h+3 hours to produce the same number of toys as 3 machines in 2 hours: 2(h+3) = 3h 2h + 6 = 3h 6 = h. Since 3 machines produce 360 toys ...”
January 14, 2019
GMATGuruNY posted a reply to If Jay has 99 problems, in how many ways can he select k of in the Data Sufficiency forum
“Rule: nCr = nC(n-r) Examples: 5C2 = 5C(5-2) = 5C3. 10C3 = 10C(10-3) = 10C7. 99C5 = 99C(99-5) = 99C94. Statement 2: Jay can select k-1 of his problems in 4851 different ways. Since 4851 is relatively small, test small values for k-1. Case 1: k-1 = 2 From 99 problems, the number of ...”
January 14, 2019
GMATGuruNY posted a reply to A tank has two water pumps Alpha and Beta and one drain Gamm in the Problem Solving forum
“Let x = 2 hours, y = 3 hours and z = 4 hours. Let the tank = 12 gallons. Since Alpha takes 2 hours to fill the 12-gallon tank, Alpha''s rate = w/t = 12/2 = 6 gallons per hour. Since Beta takes 3 hours to fill the 12-gallon tank, Beta''s rate = w/t = 12/3 = 4 gallons per hour. Since Gamma takes ...”
January 13, 2019
ceilidh.erickson posted a reply to Admissions cosultants in the The Application Process forum
“It looks like BTG has added that feature since you posted: https://reviews.beatthegmat.com/ You should also check out Poets & Quants: https://poetsandquants.com/2018/04/27/best-mba-admission-consultants/ https://poetsandquants.com/consultants/”
January 12, 2019
ceilidh.erickson posted a reply to 60Day GMAT PREP Question in the GMAT Strategy forum
“Studying without reviewing is almost entirely useless - it''s like trying to collect water with a sieve. Or trying to collect tennis balls like this: https://www.youtube.com/watch?v=L5C8rnpAbIs It is absolutely essential that you make reviewing a large part of your process. In fact, you should ...”
January 12, 2019
ceilidh.erickson posted a reply to Post-First Exam: What are my next steps? in the GMAT Strategy forum
“You mention that you''ve read most of the guides and done practice problems. There are a few things you haven''t mentioned, though: - how were you doing those practice problems? Were you doing them timed, and carefully tracking your errors? - do you have a solid understanding of test strategy as ...”
January 12, 2019
ceilidh.erickson posted a reply to Over the last five years, demand for hotel rooms in Cenopoli in the Critical Reasoning forum
“If we want to EVALUATE an argument, we need to establish the conclusion of the argument and its supporting premises. We then need to determine what information is MISSING. Premises: - demand for hotel rooms in Cenopolis has increased significantly - so has the average price Cenopolis hotels ...”
January 12, 2019
ceilidh.erickson posted a reply to Bluegrass musician Bill Monroe, whose repertory, views on in the Sentence Correction forum
“The reason "that of" redundant is that in the non-underlined portion we have "his own," which is already possessive. (This is similar to saying "my music of mine.") Since we can''t change that non-underlined part, none of the fixes you suggested would work for this ...”
January 12, 2019
ceilidh.erickson posted a reply to People with high blood pressure are generally more nervous a in the Critical Reasoning forum
“For more on how the GMAT tests correlation v. causation, see: https://www.beatthegmat.com/male-bowerbirds-construct-elaborately-decorated-nests-or-t303937.html#818930 https://www.beatthegmat.com/veritas-cat-question-doubt-t300364.html#808487 ...”
January 12, 2019
ceilidh.erickson posted a reply to People with high blood pressure are generally more nervous a in the Critical Reasoning forum
“This argument demonstrates a very common logical flaw: CORRELATION v. CAUSATION. We''re given that "people with high blood pressure are generally more nervous and anxious than people who do not have high blood pressure." In other words, these two phenomena tend to occur together. ...”
January 12, 2019
ceilidh.erickson posted a reply to Researchers have found entombed in Burmese amber a 102-milli in the Sentence Correction forum
“This question is primarily testing MODIFIERS and LOGICAL PARALLELISM. Researchers have found entombed in Burmese amber a 102-million-year-old tick grasping the feather of a Velociraptor, providing the first direct evidence that the tiny pests drank dinosaur blood. (A) entombed in Burmese ...”
January 12, 2019
ceilidh.erickson posted a reply to A new commercial radio station in Greenfield plans to play s in the Critical Reasoning forum
“The chain of logic in this argument is as follows: play songs that were popular hits fifteen to twenty-five years ago --> attract an audience made up mainly of people between thirty-five and forty-five years old --> strong market appeal to advertisers. This argument is relying on the ...”
January 12, 2019
ceilidh.erickson posted a reply to I took the GMAT today in the GMAT Strategy forum
“I''m so sorry to hear that. But you''re not alone - this test is hard, and many people don''t get the score they''re hoping for on the first try. Here are some possible explanations for why your score went down: 1. You were emphasizing content over strategy (esp timing strategy) You said ...”
January 12, 2019
Brent@GMATPrepNow posted a reply to There is a total of 120 marbles in a box, each of which is in the Problem Solving forum
“...the probability that it So, 1/4 of the 120 marbles are white. In other words, there are 30 white marbles. ...the probability that it So, 1/3 of the 120 marbles are green . In other words, there are 40 green marbles. Altogether, there are 70 marbles that are EITHER white or green. ...”
January 12, 2019
Brent@GMATPrepNow posted a reply to To furnish a room in model home, an interior decorator is to in the Problem Solving forum
“Total # of combinations = (# of ways to select 2 chairs)(# of ways to select 2 tables) So, 150 = (# of ways to select 2 chairs)(# of ways to select 2 tables) # of ways to select 2 chairs 5 tables, choose 2 of them. Since the order of the selected chairs does not matter, we can use ...”
January 11, 2019
GMATGuruNY posted a reply to To furnish a room in model home, an interior decorator is to in the Problem Solving forum
“Since 150 combinations are possible, we get: (number of ways to choose 2 chairs)(number of ways to choose 2 tables) = 150. From 5 chairs, the number of ways to choose 2 = 5C2 = (5*4)/(2*1) = 10. Thus: (10)(number of ways to choose 2 tables) = 150 number of ways to choose 2 tables = 150/10 = ...”
January 11, 2019
GMATGuruNY posted a reply to Carlos runs a lap around the track in x seconds. His second in the Problem Solving forum
“Let x = 5 seconds for the first lap, implying 10 seconds for the second lap, 3 seconds for the third lap, and a total of 18 seconds for all 3 laps. (18 seconds)/(3 laps) = (6 seconds)/(1 lap) = 1/10 minute per lap. The correct answer must yield a value of 1/10 when x=5. Only D works: (x+1)/60 ...”
January 11, 2019
GMATGuruNY posted a reply to Every day in the morning Ross cycles for 2 hours. He always in the Problem Solving forum
“The information in red is irrelevant. Only the following facts matter: Ross travels onward at a rate of 1 mile every 12 minutes. He travels home for twice the onward distance at half the onward speed. Onward speed = 1 mile per 12 minutes = 5 miles per 60 minutes = 5 mph. Let the onward ...”
January 11, 2019
GMATGuruNY posted a reply to At a certain fruit stand, the price of each apple is 40 in the Problem Solving forum
“The original total cost of the 10 pieces of fruit = 10*56 = 560. According to the answers, after 1, 2, 3, 4, or 5 oranges are removed -- so that 9, 8, 7, 6, or 5 pieces of fruit remain -- the average cost per piece decreases to 52. Since the original total cost is a multiple of 10, and the price ...”
January 11, 2019
Brent@GMATPrepNow posted a reply to At a certain fruit stand, the price of each apple is 40 in the Problem Solving forum
“It turns out that the cost per apple is irrelevant. Here''s why: The average (arithmetic mean) price of the 10 pieces of fruit is 56 cents So, (total value of all 10 pieces of fruit)/10 = 56 cents This means, total value of all 10 pieces of fruit = 560 cents How many oranges must Mary put ...”
January 11, 2019
Brent@GMATPrepNow posted a reply to A librarian has a set of ten books, including four different in the Problem Solving forum
“Take the task of arranging the 10 books and break it into stages. Stage 1: Arrange the 4 books about Abe Lincoln in a row We can arrange n objects in n! ways. So, we can arrange the 4 books in 4! ways IMPORTANT: Now we''ll "glue" the 4 Abe Lincoln books together to form 1 SUPER ...”
January 11, 2019
Brent@GMATPrepNow posted a reply to By what percent is 25 greater than 15? in the Problem Solving forum
“An alternative approach is to test the answer choices First, however, we can eliminate some answer choices by first testing an easy value: 50% Is 25 50% greater than 15? Well, 50% of 15 = 7.5 So, 50% greater than 15 = 15 + 7.5 = 22.5 22.5 is too small (we need to get 25), so we need a ...”
January 11, 2019
GMATGuruNY posted a reply to This year, x people won an Olympic medal for water in the Problem Solving forum
“Let x = the product of the two denominators in the prompt = 3*4 = 12. Since 1/3 won a medal for swimming, the number who won a medal for swimming = (1/3)(12) = 4. Since 1/4 of the medal winners for swimming also won a medal for diving, the number who won both a medal for swimming and a medal for ...”
January 10, 2019
Brent@GMATPrepNow posted a reply to The price of a phone call consists of a standard connection in the Problem Solving forum
“Let C = price of connection fee Let M = the price PER MINUTE A 10-minute call costs $2.90 We can write: C + 10M = 2.90 A 16-minute call costs $4.40. We can write: C + 16M = 4.40 How much does a 13-minute call cost? So far, we have: C + 10M = 2.90 C + 16M = 4.40 ONE (slower) ...”
January 10, 2019
Brent@GMATPrepNow posted a reply to At the end of the first quarter, the share price of a in the Problem Solving forum
“Let $100 = share price at the beginning of the year At the end of the first quarter, the share price of a certain mutual fund was 20 percent higher than it was at the beginning of the year. So, $120 = share price at the end of the first quarter At the end of the second quarter, the share ...”
January 10, 2019
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Data Sufficiency Video #1: Introduction to GMAT Data Sufficiency Video: https://www.youtube.com/watch?v=3MaEqnSnK-s Cheers, Brent”
January 10, 2019
Brent@GMATPrepNow posted a reply to 17^27 has a units digit of: in the Problem Solving forum
“Look for a pattern 17^1 = 17 17^2 = (17)(17) = ---9 17^3 = (17)(17^2) = (17)(---9) = ----3 17^4 = (17)(17^3) = (17)(---3) = ----1 17^5 = (17)(17^4) = (17)(---1) = ----7 NOTICE that we''re back to where we started. 17^5 has units digit 7, and 17^1 has units digit 7 So, at this point, ...”
January 10, 2019
GMATGuruNY posted a reply to (7+43+7-43)^2 is equal to which of the following? in the Problem Solving forum
“√3 ≈ 1.7. 7 + 4√3 ≈ 7 + (4)(1.7) = 13.8. 7 - 4√3 ≈ 7 - (4)(1.7) = 0.2. Thus, the given expression can be approximated as follows: (√13.8 + √0.2)² = a little more than 13.8. Only D is viable. The correct answer is D.”
January 10, 2019
GMATGuruNY posted a reply to PLease help me with the concept! in the Sentence Correction forum
“Offhand, I cannot cite an official SC that violates the rule discussed above.”
January 10, 2019
GMATGuruNY posted a reply to What is the greatest possible area of a triangular region in the Problem Solving forum
“Given two sides of a triangle, the greatest possible area will be achieved if the two sides form a RIGHT ANGLE and serve as the triangle''s base and height. For the problem above, I posted an illustrated solution here: ...”
January 9, 2019
Brent@GMATPrepNow posted a reply to The water from one outlet, flowing at a constant rate, can f in the Problem Solving forum
“One approach is to assign a NICE NUMBER to the volume of the swimming pool. This number will work well with the two pieces of information (fill pool in 9 hours and fill pool in 5 hours). So, let''s say that the volume of the pool is 45 gallons. The water from one outlet, flowing at a constant ...”
January 9, 2019
Brent@GMATPrepNow posted a reply to If x and y are positive, is x > y? in the Data Sufficiency forum
“Target question: Is x > y? This is a good candidate for rephrasing the target question. Since y is POSITIVE, we can safely take the inequality x > y and divide both sides by y to get: x/y > 1 REPHRASED target question: Is x/y > 1? Aside: Here’s a video with tips on rephrasing ...”
January 9, 2019
Brent@GMATPrepNow posted a reply to Emily keeps 12 different pairs of shoes (24 individual shoes in the Problem Solving forum
“P(dog selects matching pair) = P(dog chooses ANY sock 1st AND 2nd sock matches the 1st sock) = P(dog chooses ANY sock 1st) x P(2nd sock matches the 1st sock) = 24/24 x 1/23 = 1/23 Answer: C Cheers, Brent”
January 9, 2019
GMATGuruNY posted a reply to Stock - Number of shares V ------------------- 68 W ------- in the Problem Solving forum
“Original range = (greatest number of shares) - (smallest number of shares) = 112-45 = 67. After 24 shares of Y are purchased, new Y = 94+24 = 118. After 20 shares of X are sold, new X = 56-20 = 36. New range = (new greatest number of shares) - (new smallest number of shares) = 118-36 = 82. ...”
January 9, 2019
GMATGuruNY posted a reply to On a certain Monday, Carlos drove to work at an average in the Problem Solving forum
“When the SAME DISTANCE is traveled at two different speeds, the average speed for the entire trip will be CLOSER TO THE LOWER SPEED than to the higher speed. The reason: The portion traveled at the lower speed takes LONGER. Since more time is spent at the lower speed than at the higher speed, the ...”
January 8, 2019
Brent@GMATPrepNow posted a reply to On a certain Monday, Carlos drove to work at an average in the Problem Solving forum
“Average speed = (TOTAL distance)/TOTAL travel time)Carlos drove to work at an average speed of 50 miles per hour Time = distance/speed So, travel time TO work = d/50 hours Carlos drove home from work at an average speed of 70 miles per hour So, travel time FROM work = d/70 hours So, TOTAL ...”
January 8, 2019
Brent@GMATPrepNow posted a reply to How many integers between in the Problem Solving forum
“He spent 40% (of the $35) on chicken feed. 40% of $35 = $14. So, he spent $14 on chicken feed. He got a 20% discount on the chicken feed. In other words, he paid 80% of the original price. So, let C = original price of chicken feed. We can write 80% of C = $14 Or we can write 0.8C = $14 ...”
January 8, 2019
Brent@GMATPrepNow posted a reply to On Monday, the opening price of a certain stock was $100 in the Problem Solving forum
“On Monday, the opening price of a certain stock was $100 per share and its closing price was $110 per share. On Tuesday the closing price of the stock was 10 percent less than its closing price on Monday, We can say that the stock LOST 10% of its value. OR we can say that the stock RETAINED 90% ...”
January 8, 2019
GMATGuruNY posted a reply to A department manager distributed a number of pens, pencils, in the Data Sufficiency forum
“Statement 1: The numbers of pens, pencils, and pads that each staff member received were in the ratio 2:3:4, respectively. Since 2+3+4 = 9, the total number of pens + pencils + pads must be a multiple of 9. No way to determine the exact number of staff members. INSUFFICIENT. Statement 2: ...”
January 8, 2019
Brent@GMATPrepNow posted a reply to A department manager distributed a number of pens, pencils, in the Data Sufficiency forum
“Jay''s solution is great. I just wanted to mention that this question hinges largely on the fact that the number of pens, pencils, and pads that each staff member receives MUST HAVE INTEGER VALUES. So, for example, if statement 1 were different and statement 2 read "The manager ...”
January 8, 2019
Brent@GMATPrepNow posted a reply to In 1982 and 1983, Company B's operating expenses were $12.0 in the Problem Solving forum
“The profit in 1982 = 15.6 - 12.0 = $3.6 million The profit in 1983 = 18.8 - 14.0 = $4.8 million Percent change = (100)(new - old)/old = (100)(4.8 - 3.6)/3.6 = (100)(1.2)/(3.6) = (100)(1/3) = 33 1/3% Answer: D Cheers, Brent”
January 8, 2019
Brent@GMATPrepNow posted a reply to x is a positive integer, and the units digits of both (x+2)^ in the Problem Solving forum
“Another approach is to test the answer choices A. If the units digit of x is 1, is it the case that units digits of both (x+2)² and (x-2)² is 9? Well, (x+2)² = (1+2)² = 9. Works! To test (x-2)², let''s let x = 11. We get: (11-2)² = 9² = 81. NO GOOD ELIMINATE A B. If the units digit ...”
January 8, 2019
GMATGuruNY posted a reply to Because natural gas is composed mostly of methane in the Sentence Correction forum
“Both of the following are viable: Vehicles powered by natural gas emit less of certain pollutants than those burning gasoline or diesel fuel. Vehicles powered by ndatural gas emit less of certain pollutants than do those burning gasoline or diesel fuel. The inclusion of do is optional. With or ...”
January 8, 2019
GMATGuruNY posted a reply to If the graph of y = x^2 + ax + b passes through the points ( in the Data Sufficiency forum
“What is the value of n-m? (m,0) and (n,0) are the two points where y=0 and the graph intersects the x-axis. Thus, m and n are the x-intercepts of the graph. Since m < n, n-m > 0. Question rephrased: What is the positive difference between the x-intercepts? Statement 1: 4b = a²-4 Test ...”
January 8, 2019
GMATGuruNY posted a reply to If x is integer and 3 | x |+x < 4, what is the value of x in the Data Sufficiency forum
“3|x| < 4-x Case 1: Signs unchanged 3x < -x 4x < 4 x < 1 Case 2: Signs changed in the absolute value 3(-x) < 4-x -2x < 4 x > -2 Question stem, rephrased: If x is an integer such that -2 < x < 1, what is the value of x? Statement 1: x < 0 Here, x must ...”
January 8, 2019
Brent@GMATPrepNow posted a reply to In 1991, the price of a house was 80% of its original price. in the Problem Solving forum
“I''d typically assign a "nice" value to the original price, and then follow the steps that Mitch demonstrated. Alternatively, we can solve the question algebraically In 1991, the price of a house was 80% of its original price. Let x = the original price So, 0.8x = the 1991 price ...”
January 7, 2019
Brent@GMATPrepNow posted a reply to If triangle ABC is an isosceles triangle, what is ∠ABC? in the Data Sufficiency forum
“Target question: What is ∠ABC? Given: Triangle ABC is an isosceles triangle So, ∆ABC has 2 equal angles Statement 1: ∠CAB = 45 degrees Since ∆ABC has 2 equal angles, there are two possible triangles that satisfy statement 1: Case a: ∠CAB = 45, ∠BCA = 45 and ∠ABC = 90. ...”
January 7, 2019
Brent@GMATPrepNow posted a reply to If f(a*b) = f(a) + f(b), what is the value of f(1)? in the Problem Solving forum
“To generalize Mitch''s and Fabio''s solutions, notice that, as long as we can get f(1) involved in the process, we''ll arrive at answer choice C every time. Notice that k = 1*k Since f(a*b) = f(a) + f(b), we can write: f(1*k) = f(1) + f(k) Simplify: f(k) = f(1) + f(k) Subtract f(k) from both ...”
January 7, 2019
GMATGuruNY posted a reply to In 1991, the price of a house was 80% of its original price. in the Problem Solving forum
“Let the original price = 100. 1991 price = 80% of 100 = 80. 1992 price = 60% of 100 = 60. Percent decrease from 80 to 60 = (Difference/Larger) * 100 = (20/80) * 100 = 25. The correct answer is B.”
January 7, 2019
GMATGuruNY posted a reply to The main ingredient in a certain prescription drug capsule c in the Problem Solving forum
“Each capsule contains 600 milligrams of ingredient. 10⁶ milligrams = 1 kilogram. 1 kilogram of ingredient = 500 dollars. To determine the cost per capsule, we must use the relationships above to convert 600 milligrams into dollars: (600 milligrams) * (1 kilogram)/(10⁶ milligrams) * ...”
January 7, 2019
GMATGuruNY posted a reply to The numbers of women is singular or plural? in the Sentence Correction forum
“percent may serve as a NOUN. Of the students in the class, eighty percent passed the test. Here, eighty percent is a NOUN serving as the subject of passed. twice is a MODIFIER. It cannot serve as the subject of a sentence. Of the students in the class, twice passed the test. The sentence ...”
January 7, 2019
GMATGuruNY posted a reply to If f(a*b) = f(a) + f(b), what is the value of f(1)? in the Problem Solving forum
“Let a=1 and b=2. Plugging a=1 and b=2 into f(ab) = f(a) + f(b), we get: f(1*2) = f(1) + f(2) f(2) = f(1) + f(2) 0 = f(1). The correct answer is C.”
January 7, 2019
Brent@GMATPrepNow posted a reply to After her birthday, Fiona had D dollars in gift money. in the Problem Solving forum
“Another approach is to use algebra. After her birthday, Fiona had D dollars in gift money. She spent 3/5 of this on an electric skateboard. If Fiona SPENT 3/5 of D dollars, then 2/5 of D dollars REMAINED In other words, the amount remaining at the end of the day = 2D/5 dollars The next day, ...”
January 6, 2019
Brent@GMATPrepNow posted a reply to After her birthday, Fiona had D dollars in gift money. in the Problem Solving forum
“One option is to WORK BACKWARDS The next day, she spent 1/3 of what was left on a movie passcard, and then finally put the last $80 in the bank. If she spent 1/3 of her money on a movie passcard, then 2/3 of her money remained (which she put in the bank). This means 2/3 of her money = $80 We ...”
January 6, 2019
Brent@GMATPrepNow posted a reply to A retailer sells only radios and clocks. If she currently ha in the Data Sufficiency forum
“ Given: A retailer sells only radios and clocks, and she currently has 44 total items in inventory. Target question: How many radios are there in the inventory Statement 1: The retailer has more than 28 radios in inventory There are several scenarios that satisfy statement 1. Here are ...”
January 6, 2019
Brent@GMATPrepNow posted a reply to Number Properties in the Data Sufficiency forum
“The error is highlighted above in blue. if a>0 we will have the answer as YES is ALMOST true. The only time it''s not true is when a = 1 If a = 1, then the answer is NO. We can verify this using either the original inequality or the rephrased inequality. Take "Is a + 1/a > ...”
January 6, 2019
GMATGuruNY posted a reply to A store sells erasers for 0.23$ per piece and pencil for in the Data Sufficiency forum
“Consider the following equation: 5x + 7y = 70. If x and y are nonnegative integers, the following solutions are possible: x=0, y=10 x=7, y=5 x=14, y=0. Notice the following: The value of x changes in increments of 7 (the coefficient for y). The value of y changes in increments of 5 (the ...”
January 6, 2019
GMATGuruNY posted a reply to the mixture to make the ratio of milk and water in the new m in the Problem Solving forum
“The ratio of milk and water in a mixture is 2:1, Let milk = 2 liters and water = 1 liter. Some quantity of water is added to the mixture to make the ratio of milk and water in the new mixture 1:2. Since the resulting amount of water must be double the original 2 liters of milk, the resulting ...”
January 6, 2019
GMATGuruNY posted a reply to Little Texas Drilling Company has three wells, each producin in the Problem Solving forum
“Given the answer choices, the prompt should read as follows: A''s rate = (1 barrel)/(2 minutes) * (60 minutes)/(1 hour) = 30 barrels per hour. B''s rate = (1 barrel)/(3 minutes) * (60 minutes)/(1 hour) = 20 barrels per hour. C''s rate = (1 barrel)/(15 minutes) * (60 minutes)/(1 hour) = 15 ...”
January 6, 2019
GMATGuruNY posted a reply to If y = |2 + x| - |2 – x| and |2x – 15| < 2, how many in the Problem Solving forum
“|a-b| = the distance between a and b |a+b| = |a-(-b)| = the distance between a and -b y = |2 + x| - |2 – x| y = |x+2| - |x-2| y = |x-(-2)| - |x-2| y = the subtraction of two distances: (distance between x and -2) - (distance between x and 2) On the number line: ...”
January 5, 2019
GMATGuruNY posted a reply to Seven cars of seven different models are going to park in in the Problem Solving forum
“Let the 7 cars be A, B, C, D, P, Q and S. Since P and Q must occupy adjacent positions, consider PQ a single element in the arrangement. The number of ways to arrange the 6 elements A, B, C, D, PQ and S = 6! = 720. In 1/2 of these arrangements, S will be to the LEFT of PQ. In the ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to A store sells erasers for 0.23$ per piece and pencil for in the Data Sufficiency forum
“This question illustrates a common trap on the GMAT. As Jay has shown, with statement 2, we''re able to write the equation 23x + 11y = 170 , and in high school we learned that, if we''re given 1 equation with 2 variables, we cannot find the value of either variable. However, if we restrict the ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to A barn is enclosed in the shape of a 6-sided figure; all in the Data Sufficiency forum
“This Date Sufficiency question is almost identical to the following Problem Solving question, which requires us to find the actual area: http://www.beatthegmat.com/plz-explain-t270003.html Cheers, Brent”
January 5, 2019
Brent@GMATPrepNow posted a reply to In the rectangular coordinate system above, the area of in the Problem Solving forum
“Let''s draw a rectangle around the triangle (as shown below) and then subtract from the rectangle''s area (28) the areas of the 3 right triangles that surround the triangle in question. We get the following: http://s13.postimage.org/a47qx0j8j/triangle_in_coordinate_plane_2.jpg So, the area ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to What is the perimeter of quadrilateral Q? in the Data Sufficiency forum
“Target question: What is the perimeter of quadrilateral Q? If we recognize that each statement alone is not sufficient, we can jump straight to...... Statements 1 and 2 combined There are several quadrilaterals satisfy BOTH statements. Here are two: Case a: Q is a rectangle with width 1 ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to The price of a consumer good increased by p% in the Problem Solving forum
“Let $100 be the original price The price of a consumer good increased by p% during 2012 p% = p/100, so a p% INCREASE is the same a multiplying the original price by 1 + p/100 So, the new price = ($100)(1 + p/100) The price then decreased by 12% during 2013 A 12% DECREASE is the same a ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to The number of students who attend a school could be divided in the Problem Solving forum
“The number of students who attend a school could be divided among 10, 12, or 16 buses, such that each bus transports an equal number of students. This tells us that the TOTAL number of students is a multiple of 10, 12 and 16 What is the minimum number of students that could attend the school? ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to Set K consists of a finite number of consecutive odd in the Data Sufficiency forum
“Target question: What is the value of y - x? Given: Set K consists of a finite number of consecutive odd integers Statement 1: The average (arithmetic mean) of set K is –36 There''s a nice rule that says, "In a set where the numbers are equally spaced, the mean will equal the ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to The value of (10^8-10^2)/(10^7-10^3) is closest to which in the Problem Solving forum
“Since the answer choices are so spread out, we can be quite aggressive with out estimation. First, 10⁸ - 10² can be rounded to 10⁸ Is this reasonable? Well, 10⁸ equals 100,000,000, so subtracting 10² (aka 100) from 100,000,000 still leaves us with approximately 100,000,000 ...”
January 5, 2019
GMATGuruNY posted a reply to Which of the following must be non-negative? in the Problem Solving forum
“D: (a-0.9)(a-0.9) = (a-0.9)². The square of a value cannot be negative. The correct answer is D.”
January 5, 2019
GMATGuruNY posted a reply to Machine M and Machine N working alone at their constant rate in the Data Sufficiency forum
“Statement 1: Case 1: N = 4000 nails per hour, M = 2000 nails per hour Since N''s rate = 4000 nails per hour, the time for N to produce 8000 nails = 8000/4000 = 2 hours. Since M''s rate = 2000 nails per hour, the time for M to produce 6000 nails = 6000/2000 = 3 hours. In this case, M works longer ...”
January 5, 2019
Brent@GMATPrepNow posted a reply to Each of the 25 balls in a certain box is either red, blue, in the Data Sufficiency forum
“Target question: What is the value of P(white or even)? To solve this, we need P(A or B) = P(A) + P(B) - P(A & B) So, P(white or even) = P(white) + P(even) - P(white & even) Statement 1: P(white & even) = 0 We can add this to our probability equation to get: P(white or even) = ...”
January 4, 2019
GMATGuruNY posted a reply to Each of the 25 balls in a certain box is either red, blue, in the Data Sufficiency forum
“Let: W = the total number of white marbles. E = the total number of even marbles. WE = the total number of white even marbles. Statement 1: Thus, WE = 0. No way to determine the value of W or E. INSUFFICIENT. Statement 2: Implication: W-E = (0.2)(25) = 5. Case 1: W=10, E=5, WE=0 ...”
January 4, 2019
GMATGuruNY posted a reply to Allison always leaves her office at 5.00pm and reaches her in the Data Sufficiency forum
“Statement 2: Brittany always leaves the hotel at exactly 5.30pm. To see the situation more clearly, plug in a value for the distance between the hotel and the office. Let the distance = 6 miles. Since Allison takes 1 hour -- from 5 to 6pm -- to travel the entire distance, Alison''s rate = d/t = ...”
January 4, 2019
Brent@GMATPrepNow posted a reply to The profit from the sale of a certain appliance increases, in the Data Sufficiency forum
“Target question: Did the profit exceed $4 million on sales of 380,000 units? Given: The profit from the sale of a certain appliance increases, though not proportionally, with the number of units sold. IMPORTANT: This means that we CANNOT make any "good" assumptions about the ...”
January 4, 2019
GMATGuruNY posted a reply to If y = 2 + 2K and y≠0y≠0, then 1/y + 1/y + 1/y + 1/y = ? in the Problem Solving forum
“Let k=0, implying that y = 2 + 2*0 = 2. Plugging y=2 into 1/y + 1/y + 1/y + 1/y, we get: 1/2 + 1/2 + 1/2 + 1/2 = 2. The correct answer must yield a value of 2 when k=0. Only B works: 2/(1+k) = 2/(1+0) = 2. The correct answer is B.”
January 4, 2019
Brent@GMATPrepNow posted a reply to If y = 2 + 2K and y≠0y≠0, then 1/y + 1/y + 1/y + 1/y = ? in the Problem Solving forum
“Given: y = 2 + 2k Rewrite as: y/1 = (2 + 2k)/1 Flip both fractions to get: 1/y = 1/(2 + 2k) So, 1/y + 1/y + 1/y + 1/y = 1/(2 + 2k) + 1/(2 + 2k) + 1/(2 + 2k) + 1/(2 + 2k) = 4/(2 + 2k) = 4/(2)(1 + k) = 2/(1 + k) Answer: B Cheers, Brent”
January 4, 2019
Brent@GMATPrepNow posted a reply to Is x/y < 0? in the Data Sufficiency forum
“Target question: Is x/y < 0? Statement 1: (x^4)(y^5) < 0 There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = -1. Notice that (x^4)(y^5) = (1^4)(-1^5) = (1)(-1) = -1, which is less than 0. In this case, x/y = 1/(-1) = -1. So, the answer to ...”
January 4, 2019
GMATGuruNY posted a reply to OG Verbal 2016-SC# 63 in the Sentence Correction forum
“In my previous response, I provided links to three official examples. This construction seems viable.”
January 4, 2019
GMATGuruNY posted a reply to OG Verbal 2016-SC# 63 in the Sentence Correction forum
“It is possible for back-to-back modifiers joined solely by a comma to have the same referent. Three examples: http://www.beatthegmat.com/the-hognose-snake-puts-on-an-impressive-bluff-t93558.html http://www.beatthegmat.com/parallelism-issue-t96011.html ...”
January 4, 2019
GMATGuruNY posted a reply to In a sports club, 6 players are divided into 3 teams of 2 pl in the Problem Solving forum
“The usage of the term arrangements is misleading. The prompt seems intended to ask the following: The first player selected can be paired with any of the 5 other players. Thus, the number of options for the first player selected = 5. At this point, 4 players remain. The next player ...”
January 4, 2019
Brent@GMATPrepNow posted a reply to If 4+ 1n = 55n, what is the value of n? in the Problem Solving forum
“GIVEN: √(4 + 1/n) = 5√(5/n) Square both sides to get: (5)(5)√(5/n)√(5/n) Simplify right side again: 4 + 1/n = 25(5/n) Simplify right side: 4 + 1/n = 125/n Multiply both sides by n to get: 4n + 1 = 125 Subtract 1 from both sides to get: 4n = 124 Solve: n = 124/4 =31 Answer: A ...”
January 3, 2019
Brent@GMATPrepNow posted a reply to On a construction site, 16 of the men wear helmets, and 19 in the Data Sufficiency forum
“I thought I''d point out that Jay''s approach is also known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of construction worker, and the two ...”
January 3, 2019
Brent@GMATPrepNow posted a reply to If the average of four numbers is 35, how many of the in the Data Sufficiency forum
“Target question: How many of the numbers are less than 35? Given: The average of four numbers is 35 All this tells us is that the SUM of the 4 numbers is 140 (since 140/4 = 35) Given the limited amount of information, it''s likely that the correct answer is C or E Statement 1: None of ...”
January 3, 2019
GMATGuruNY posted a reply to This morning, a certain sugar container was full. Since then in the Data Sufficiency forum
“The determine the percent decrease, we need to know the RATIO between the remaining amount of sugar after cookie-making and the original amount of sugar. Statement 1: Case 1: Remaining sugar after cookie-making = 10 pounds Since the remaimning amount of sugar would need to increase by 30% to ...”
January 3, 2019
GMATGuruNY posted a reply to Is x/y < 0? in the Data Sufficiency forum
“Question stem, rephrased: Do x and y have different signs? Statement 1: |x+y| < |x|+|y| Since an absolute value cannot be negative, both sides here are NONNEGATIVE, enabling us to safely square the inequality: (|x+y|)²< (|x|+|y|)² x² + y² + 2xy < x² + y² + 2|x||y| xy < ...”
January 3, 2019
GMATGuruNY posted a reply to If the average of four numbers is 35, how many of the in the Data Sufficiency forum
“Sum of the 4 numbers = (quantity)(average) = 4*35 = 140. Statement 1: None of the numbers are exactly 3 To save time, check whether it''s possible to get different answers to the question stem while also satisfying Statement 2. Case 1: 0, 33, 33, 74 --> sum = 0+33+33+74 = 140 In this ...”
January 3, 2019
GMATGuruNY posted a reply to If a car traveled from Townsend to Smallville at an average in the Data Sufficiency forum
“Statement 1: The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. Case 1: Distance between Townsend and Smallville = 80 miles Time to travel from Townsend to Smallville at a speed of 40 mph = 80/40 = 2 hours. Time to travel from Smallville to Townsend = ...”
January 3, 2019
GMATGuruNY posted a reply to On each lab that René completed he received either 100 in the Data Sufficiency forum
“Let x = the number of 100-point labs and y = the number of 85-point labs. Question stem, rephrased: What is the value of x? Statement 1: 100x + 85y = 1140 20x + 17y = 228 The value in blue implies the following: Since 20x will have a units digit of 0, 17y must have a UNITS DIGIT OF 8. ...”
January 3, 2019
GMATGuruNY posted a reply to Absolute value in the Problem Solving forum
“Alternate approach: Since an absolute value cannot be negative -- implying that the right side of the equation must be NONNEGATIVE -- we know that x≥0. If x²-6=x, we get: x²-x-6=0 (x-3)(x+2) = 0 Only the factor in green implies a nonnegative option for x: x-3=0 x=3. The correct ...”
January 3, 2019
Brent@GMATPrepNow posted a reply to Absolute value in the Problem Solving forum
“A quick approach is to simply test the answer choices A) -2 No good. The absolute value of something cannot be negative B) 0 Plug in to get |0² - 6| = 0. Doesn''t work. C) 1 Plug in to get |1² - 6| = 1. Doesn''t work. D) 3 Plug in to get |3² - 6| = 3. WORKS!!! Answer: D Cheers, ...”
January 3, 2019
Brent@GMATPrepNow posted a reply to If m and n are positive integers such that m>n, what is t in the Data Sufficiency forum
“ Given: m and n are positive integers such that m > n Target question: What is the remainder when m² – n² is divided by 21? Statement 1: The remainder when (m + n) is divided by 21 is 1 There are several values of m and n that satisfy statement 1. Here are two: Case a: m = 12 and ...”
January 2, 2019
Brent@GMATPrepNow posted a reply to If x + y is not equal to 0. What is the value of (ax + ay)/( in the Data Sufficiency forum
“Target question: What is the value of (ax + ay)/(x + y)? This is a good candidate for rephrasing the target question. Take the expression: (ax + ay)/(x + y) Factor the numerator to get: a(x + y)/(x + y) Simplify the fraction to get: a Since (ax + ay)/(x + y) = a, we can rephrase the target ...”
January 2, 2019
Brent@GMATPrepNow posted a reply to Can n be expressed as the difference of 2 prime numbers? in the Data Sufficiency forum
“Target question: Can n be expressed as the difference of 2 prime numbers? Statement 1: (n-17)(n-21) = 0 This tells us that EITHER n = 17 OR n = 21 IMPORTANT: Upon seeing that n can equal one of two values, some students will incorrectly conclude that statement 1 is not sufficient. However, ...”
January 2, 2019
GMATGuruNY posted a reply to What is the units digit of the number z? in the Data Sufficiency forum
“The usage of number implies that we should consider NON-INTEGER values. Both statements are satisfied by z=18.1 and z=19.1 Since the units digit of z can be different values, the two statements combinecd are INSUFFICIENT. The correct answer is E.”
January 2, 2019
Brent@GMATPrepNow posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum
“In order to minimize the number of homeowners, we must MAXIMIZE the number of men in the group, since the proportion of male homeowners (20%) is less than the proportion of female homeowners (25%) So, let''s see what happens if there are 199 men and 1 woman. If 20% (aka 1/5) of the men are ...”
January 1, 2019
Brent@GMATPrepNow posted a reply to What is the value of the integer n? in the Data Sufficiency forum
“Target question: What is the value of the integer n? Statement 1: n is a prime factor of 21 21 = (3)(7) So, EITHER n = 3 OR n = 7 Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: n is a factor of 49 49 has three positive factors: 1, ...”
January 1, 2019
Brent@GMATPrepNow posted a reply to If 2x+y=3 and 4x^2-4xy+y^2=1, what is the value of xy? in the Problem Solving forum
“This question becomes a lot easier if we recognize that (2x + y)² = 4x² + 4xy + y² (which is VERY similar to 4x² - 4xy + y²) Here''s what I mean: Take 2x + y = 3 and square both sides to get: (2x + y)² = 3² Simplify both sides to get: 4x² + 4xy + y²= 9 We now have two (quite ...”
January 1, 2019
GMATGuruNY posted a reply to Is √(x+1)^2=x+1 ? in the Data Sufficiency forum
“√(a²) = |a|. Question stem, rephrased: Is |x+1| = x+1? The answer will be YES if x+1 is NONNEGATIVE: x+1≥0 x≥-1. Question stem, rephrased again: Is x≥-1? Statement 1: x=0 or x=2. Since x≥-1 in both cases, the answer to the question stem is YES. SUFFICIENT. Statement 2: ...”
December 31, 2018
GMATGuruNY posted a reply to If f(x)=1-(1/x), then f(f(f(x)))=? in the Problem Solving forum
“Let x=2 and apply the function three times: f(2) = 1 - 1/2 = 1/2. f(1/2) = 1 - 1/(1/2) = -1. f(-1) = 1 - (1/-1) = 2. The correct answer must yield a value of 2 when x=2. Only A works. The correct answer is A.”
December 31, 2018
GMATGuruNY posted a reply to Singular or Plural Verb with None in the Sentence Correction forum
“Any BAG taken on the subway IS subject to search by the police. Any BAGS taken on the subway ARE subject to search by the police. In each of these sentences, any is a MODIFIER describing the subject in blue. In the first sentence, the verb (is) is SINGULAR to match the singular subject in blue. ...”
December 31, 2018
GMATGuruNY posted a reply to Brady, Charlie, and Daryl play on the same baseball team. Th in the Data Sufficiency forum
“Statement 1: No information about Charlie or Daryl. INSUFFICIENT. Statement 2: For every 2 home run hits made by Charlie and Daryl combined, Brady made 4 home run hits, implying that Brady made 4 of every 6 home run hits: 4/6 = 2/3. SUFFICIENT. The correct answer is B.”
December 31, 2018
Brent@GMATPrepNow posted a reply to Given four rods of length 1 meter, 3 meters, 5 meters, and 7 in the Problem Solving forum
“IMPORTANT RULE: If two sides of a triangle have lengths A and B, then . . . DIFFERENCE between A and B < length of third side < SUM of A and B Let''s focus on this part: length of third side < SUM of A and B We can also say that the length of LONGEST side must be less than the SUM of ...”
December 31, 2018
Brent@GMATPrepNow posted a reply to Brady, Charlie, and Daryl play on the same baseball team. Th in the Data Sufficiency forum
“ Given: Brady, Charlie, and Daryl play on the same baseball team. Target question: The number of home runs hit by Brady in a particular season is what fraction of the total home runs hit by the three players in that season? This is a good candidate for rephrasing the target question. Let ...”
December 31, 2018
Brent@GMATPrepNow posted a reply to What is the 1st term in sequence S ? (1) The 3rd term in S in the Data Sufficiency forum
“Target question: What is the 1st term in sequence S ? Statement 1: The 3rd term in S is 2 Since we''re not given any information about the NATURE of the sequence, there''s no way to answer the target question with certainty. So, statement 1 is NOT SUFFICIENT Statement 2: The 2nd term in ...”
December 31, 2018
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Here''s our video on Weighted Averages video: https://www.youtube.com/watch?v=B7J6lr_qBG4 Cheers, Brent”
December 31, 2018
GMATGuruNY posted a reply to Skier Lindsey Vonn completes a straight 300-meter downhill r in the Problem Solving forum
“Downhill speed - uphill speed = (x+10) - (x-8) = 18. Implication: The downhill speed is 18 mps greater than the uphill speed. We can PLUG IN THE ANSWERS, which represent the downhill speed. Since the downhill speed is 18 mps greater than the uphill speed, the correct answer must be GREATER ...”
December 31, 2018
Brent@GMATPrepNow posted a reply to Marcia's bucket can hold a maximum of how many liters of wat in the Data Sufficiency forum
“Target question: Marcia''s bucket can hold a maximum of how many liters of water? In other words, what is the TOTAL CAPACITY of Marcia''s bucket? Statement 1: The bucket currently contains 9 liters of water. Not enough info to determine the TOTAL CAPACITY of Marcia''s bucket. Since we ...”
December 30, 2018
Brent@GMATPrepNow posted a reply to In a stack of boards at a lumber yard, the 20th board counti in the Problem Solving forum
“Let''s start from the bottom and work our way up: We''ll start with the 16th board counting from the bottom of the stack Right BELOW that 16th board, we have a board that we''ll call Larry. So, Larry is the 15th board counting from the bottom of the stack. So, starting from the bottom and ...”
December 30, 2018
GMATGuruNY posted a reply to Two dogsled teams raced across a 300 mile course in Wyoming. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent B''s speed. When the correct answer is plugged in, B''s time - A''s time = 3 hours. For each team: Time = distance/speed = 300/speed. B: B''s speed = 15 mph, implying that A''s speed = 15+5 = 20 mph In this case, B''s time - A''s time = 300/15 - ...”
December 30, 2018
GMATGuruNY posted a reply to In a stack of boards at a lumber yard, the 20th board counti in the Problem Solving forum
“1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 = 16 20 = 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 In the rendering above: The red values represent the number of boards when counting from the TOP. The blue values represent the number of boards when counting from the ...”
December 30, 2018
GMATGuruNY posted a reply to If the original price of an item in a retail store is marked in the Data Sufficiency forum
“Let the original price = 100. Then the markup = (m/100)*100 = m. The resulting price = 100+m. The subsequent discount = d/100*(100+m) = d + md/100 Thus, the total percent change = percent increase - percent decrease = m - d - md/100. For the final price to be greater than the original price, ...”
December 30, 2018
Brent@GMATPrepNow posted a reply to Overlapping Sets in the Data Sufficiency forum
“I thought I''d point out that Manasa3190''s approach is known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of people, and the two characteristics are: ...”
December 30, 2018
Brent@GMATPrepNow posted a reply to Car X left Town T (RATE PROBLEM, Need Help) in the Problem Solving forum
“IMPORTANT: Let''s use HOURS throughout our solution, and then convert hours to minutes at the end. When car Y had traveled for z HOURS, car Y had traveled 23 miles more that car X had from the time that car X left Town T. z = car Y''s travel time in HOURS So, z + 3/10 = car X''s travel time in ...”
December 28, 2018
GMATGuruNY posted a reply to Mark has fewer than 9 coins. Each coin is either a quarter in the Data Sufficiency forum
“Statement 1: To MINIMIZE the number of coins so that a sum of 170 cents is yielded by at most 8 coins, we must MAXIMIZE the number of quarters. Since 7*25 = 175 cents, the number of quarters must be less than 7. 170 cents will be yielded by 6 quarters (totaling 150 cents) and 2 dimes (totaling 20 ...”
December 28, 2018
GMATGuruNY posted a reply to Pumping alone at their respective constant rates, one inlet in the Problem Solving forum
“Let the tank = 36 gallons. Since the first pipe takes 3 hours to fill 1/2 the tank -- and (1/2)(36) = 18 gallons -- the rate for the first pipe = w/t =18/3 = 6 gallons per hour. Since the second pipe takes 6 hours to fill 2/3 of the tank -- and (2/3)(36) = 24 gallons -- the rate for the second ...”
December 27, 2018
GMATGuruNY posted a reply to Solution A is 20% salt and Solution B is 80% salt. If you in the Problem Solving forum
“Since the desired salt percentage -- 50% -- is HALFWAY between the salt percentages for A and B (20% and 80%), the resulting solution must contain equal amounts of A and B. The correct answer is C.”
December 27, 2018
GMATGuruNY posted a reply to If the ratio of the price of 1 kilogram Camembert cheese to in the Data Sufficiency forum
“What is the value of T-C? Statement 1: T:B = 4:5. To combine T:B = 4:5 and C:B = 5:8, the element common to both ratios -- B -- must be represented by the SAME VALUE in each: T:B = 4:5 = 32:40. C:B = 5:8 = 25:40. Combining the two ratios, we get: C:T:B = 25:32:40. Case 1: T=32 and C=25, ...”
December 26, 2018
GMATGuruNY posted a reply to In a village of 100 households, 75 least one DVD player, 80 in the Problem Solving forum
“Let D = DVD owners, C = cellphone owners, and M = MP3 owners. T = D + C + M - (DC + DM + CM) - 2(DCM). The big idea with overlapping group problems is to SUBTRACT THE OVERLAPS. When we add together everyone in D, everyone in C, and everyone in M: Those in exactly 2 of the groups (DC + DM + ...”
December 26, 2018
GMATGuruNY posted a reply to A certain punch contains grape juice, orange juice, and in the Problem Solving forum
“The sum of the parts of the ratio = 2+3+7 = 12. Thus -- of every 12 ounces -- 2 ounces are grape juice, 3 ounces are orange juice, and 7 ounces are pineapple juice. Since grape juice constitutes 2 of every 12 ounces, the amount of grape juice is equal to 2/12 of the total: (2/12)(156) = 2*13 = ...”
December 26, 2018
GMATGuruNY posted a reply to If x is a factor of positive integer y, then which of the fo in the Problem Solving forum
“Strategy: Try to show that four of the answer choices do NOT have to be positive. Case 1: x=1 and y=1 In this case, A, B and D are not positive. Eliminate A, B and D. Case 2: x=1 and y=2 In this case, C is not positive. Eliminate C. The correct answer is E.”
December 26, 2018
GMATGuruNY posted a reply to The sum of 4 different odd integers is 64. What is the value in the Data Sufficiency forum
“Statement 1: Since the numbers are EVENLY SPACED, median = sum/count: 64/4 = 16. Since the median = 16, the 4 odd integers must be as follows: 13, 15, 17, 19. Thus, the greatest of the 4 odd integers = 19. SUFFICENT. Statement 2: The 4 odd integers yielded by Statement 1 -- 13, 15, 17, 19 ...”
December 26, 2018
GMATGuruNY posted a reply to If x^2+y^2=28 and xy=11, what is the value of (x+y)^2? in the Problem Solving forum
“Every test-taker should know the following quadratic identities: (x+y)² = x² + y² + 2xy (x-y)² = x² + y² - 2xy (x+y)(x-y)² = x² - y² Substituting x²+y²=28 and xy=11 into (x+y)² = x² + y² + 2xy, we get: (x+y)² = 28 + 2*11 = 50. The correct answer is C. An alternate ...”
December 25, 2018
GMATGuruNY posted a reply to There are 10 books on a shelf: 5 English books, 3 Spanish bo in the Problem Solving forum
“P(2 different languages) = 1 - P(2 of the same language). Case 1: P(2 English books are selected) P(1st book is English) = 5/10. (Of the 10 books, 5 are English.) P(2nd book is English) = 4/9. (Of the 9 remaining books, 4 are English.) To combine these probabilities, we multiply: 5/10 * 4/9 = ...”
December 25, 2018
GMATGuruNY posted a reply to If the farmer sells 75 of his chickens, his stock of feed wi in the Problem Solving forum
“Total amount of feed = (number of chickens)(number of days). The number of chickens is INVERSELY PROPORTIONAL to the number of days. If the number of chickens DOUBLES, then the feed will last for 1/2 the number of days. If the number of chickens TRIPLES, then the feed will last for 1/3 the ...”
December 24, 2018
Brent@GMATPrepNow posted a reply to A shipping company has four empty trucks that will head out in the Problem Solving forum
“Take the task of shipping the 4 boxes and break it into stages. Let''s call the 4 boxes A, B, C and D Stage 1: Select a truck to ship box A in There are 4 trucks from which to choose, so we can complete stage 1 in 4 ways Stage 2: Select a truck to ship box B in There are 4 trucks ...”
December 24, 2018
Brent@GMATPrepNow posted a reply to resolution in the Data Sufficiency forum
“ Given: A quorum of at least half the 20 directors must pass the resolution by at least a two-thirds majority Target question: At a meeting of the board of directors, did resolution X pass or fail?  Statement 1: Ten directors voted for the resolution.  KEY: We don''t know how many ...”
December 23, 2018
Brent@GMATPrepNow posted a reply to a data from gmat forum in the Data Sufficiency forum
“ Given: Every student at the Performing Arts Academy must take at least one of the two drama courses offered, Classical Theater or Improvisation. 15% of the students who take Classical Theater also take Improvisation Let''s use the Every student at the Performing Arts Academy must take at least ...”
December 23, 2018
Brent@GMATPrepNow posted a reply to Tough Rate problem in the Data Sufficiency forum
“ Given: At a certain department store present-wrapping counter, each clerk will wrap no fewer than twenty and no more than thirty presents per hour. Target question: If seventy people are standing in line, will all of their presents be wrapped after one hour? Statement 1: Each person in ...”
December 23, 2018
GMATGuruNY posted a reply to While driving on a highway, Harry and Ron crossed checkpoint in the Problem Solving forum
“9am-10am: Since Harry reaches checkpoint P at 9am -- and travels at rate of 30 mph -- from 9am to 10am Harry travels 30 miles beyond checkpoint P. Thus, when Ron reaches checkpoint P at 10am, he is 30 miles behind Harry. Checkpoint Q: When people compete, SUBTRACT THEIR RATES. Every hour Ron ...”
December 23, 2018
Brent@GMATPrepNow posted a reply to Two trees have a combined height of 60 feet, and the taller in the Problem Solving forum
“Let y = the height of the shorter tree The taller tree is x times the height of the shorter tree. Ho So, yx = the height of the taller tree The two trees have a combined height of 60 feet We can write: y + yx = 60 How tall is the shorter tree, in terms of x? We must solve the equation ...”
December 22, 2018
Brent@GMATPrepNow posted a reply to Two water pumps, working simultaneously at their respective in the Problem Solving forum
“Let''s pick some nice numbers that adhere to the given information. ...the constant rate of one pump was 1.5 times the constant rate of the other So, the fast pump has a pumping rate that''s 1.5 faster then the slow pump. So, let''s say the SLOW pump pumps at 2 gallons per hour This means ...”
December 22, 2018
Brent@GMATPrepNow posted a reply to Fractions/Ratios in the Data Sufficiency forum
“ Given: There are two types of rolls on a counter, plain rolls and seeded rolls. Let P = # of plain rolls Let S = # of seeded rolls Target question: What is the value of P + S? Statement 1: The ratio of the number of seeded rolls on the counter to the number of plain rolls on the ...”
December 21, 2018
Brent@GMATPrepNow posted a reply to Five friends - Ross, Phoebe, Chandler, Joey and Monica - in the Problem Solving forum
“Take the task of feeding the 5 friends and break it into stages. We’ll begin with the most restrictive stage(s). Stage 1: Select a pizza for Phoebe Since Phoebe will only eat Margherita pizza, there''s only 1 pizza we can serve her. So, we can complete stage 1 in 1 way Stage 2: ...”
December 21, 2018
GMATGuruNY posted a reply to Work/Rate in the Data Sufficiency forum
“Let J = the number of hours that John works. Since John assembles 3 chairs per hour, the number of chairs assembled by John = 3J. Let L = the number of hours that Larry works. Since Larry assembles 4 chairs per hour, the number of chairs assembled by Larry = 4L. Since John and Larry work a total ...”
December 21, 2018
GMATGuruNY posted a reply to Five friends - Ross, Phoebe, Chandler, Joey and Monica - in the Problem Solving forum
“Number of options for Phoebe = 1. (Must be Margherita.) Number of options for Ross = 3. (Of the 4 remaining pizzas, any but Hawaiian.) Number of options for Chandler = 3. (Any of the 3 remaining pizzas.) Number of options for Joey = 2. (Either of the 2 remaining pizzas.) Number of options for ...”
December 21, 2018
Brent@GMATPrepNow posted a reply to A list kept at Town Hall contains that town's average daily in the Data Sufficiency forum
“Target question: Does this month have 30 or 31 days? IMPORTANT: Notice that the question does not ask "How many days are in this month?" If that were the case, then we''d have to consider February. Instead, the question is ruling out February by basically telling us that the month in ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to In how many ways can the letters D, I, G, I, T be arranged in the Problem Solving forum
“One approach is to count all possible arrangements (that may or may not break the given rule) and then subtract all outcomes the break the rule. Here''s another approach. Take the task of arranging the 5 letters and break it into stages. Stage 1: Arrange the 3 CONSONANTS (D, G and T) in a ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to Inequalities in the GMAT Math forum
“Target question: Is x² > y²? Statement 2: x > y There are several values of x and y that satisfy statement 2. Here are two: Case a: x = 2 and y = 1. In this case, x² = 4 and y² = 1. So, the answer to the target question is YES, x² IS greater than y² Case b: x = -2 and y = -3. ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to If sequence S has 120 terms, what is the 105th term of S? in the Data Sufficiency forum
“Target question: What is the 105th term of S? Given: Sequence S has 120 terms Statement 1: The first term of S is −8. We have no information about the nature of the sequence. So, knowing the value of term 1 won''t help is determine the value of term 105 Since we cannot answer the ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to Two dice, each with six sides numbered 1 through 6, are toss in the Problem Solving forum
“P(both dice will come up with either a 1 or a 2) = P(1st die is 1 or 2 AND 2nd die is 1 or 2) = P(1st die is 1 or 2) x P(2nd die is 1 or 2) = 2/6 x 2/6 = 1/3 x 1/3 = 1/9 Answer: C Cheers, Brent”
December 20, 2018
Brent@GMATPrepNow posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom apart in the Problem Solving forum
“A fast and easy approach is to assign a "nice" value to the monthly rent of a ONE-bedroom apartment. Let''s say the rent on a ONE-bedroom apartment is $100 per month A two-bedroom apartment costs 50% more to rent than a one-bedroom apartment 50% of $100 = $50 So, the rent on a ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to If the remainder when positive integer x is divided by 7 is in the Data Sufficiency forum
“Target question: What is the value of x? Given: If the remainder when positive integer x is divided by 7 is 4 When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For ...”
December 20, 2018
GMATGuruNY posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom apart in the Problem Solving forum
“Let the monthly rent for a one-bedroom apartment = $2, implying that the monthly rent for a two-bedroom apartment = 2 + (50% of 2) = 2 + 1 = $3. Since the monthly rent for a one-bedroom apartment = $2, the total amount required to rent a one-bedroom apartment for 12 months = 2*12 = 24. If Alex ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to The value of a share was 25% less in the 2nd quarter over in the Problem Solving forum
“Let''s assign a nice value to the share value in the 1st quarter. Let''s say the share value in the 1st quarter = $100 The value of a share was 25% less in the 2nd quarter over the 1st quarter . . . So, the share value in the 2nd quarter = $100 - (25% of $100) = $100 - $25 = $75 . . . ...”
December 20, 2018
Brent@GMATPrepNow posted a reply to The usual price of a bagel was reduced during a sale. How in the Data Sufficiency forum
“Target question: How much money could be saved by purchasing 10 bagels at the sale price rather than at the usual price? Statement 1: The usual price for a bagel is $0.50 per bagel. Since there''s no information about the SALE price, there''s no way to calculate the amount saved. Since we ...”
December 20, 2018
GMATGuruNY posted a reply to absolute value in the Problem Solving forum
“The CRITICAL POINTS are where the expressions inside the absolute values are equal to 0. x+5 = 0 when x=-5. Substituting x=-5 into y = |x+5|-|x-5|, we get: y = |-5+5| - |-5-5| = 0-10 = -10. x-5 = 0 when x=5. Substituting x=5 into y = |x+5|-|x-5|, we get: y = |5+5| - |5-5| = 10-0 = ...”
December 19, 2018
GMATGuruNY posted a reply to One woman and one man can build a wall together in two hours in the Problem Solving forum
“One woman and one man can build a wall together in two hours, but the woman would need the help of two girls in order to complete the same job in the same amount of time. Since replacing 1 man with 2 girls does not change the amount of time required to complete the job, 1 man is the equivalent of 2 ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to One woman and one man can build a wall together in two hours in the Problem Solving forum
“One approach is to determine the size of the job One woman and one man can build a wall together in two hours, but the woman would need the help of two girls in order to complete the same job in the same amount of time. The part in blue tells us that 2 girls have the same output as 1 man. ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to Is x > 0 ? (1) |x+3| < 4 (2) |x-3| < 4 in the Data Sufficiency forum
“When solving inequalities involving ABSOLUTE VALUE, there are 2 things you need to know: Rule #1: If |something| < k, then –k < something < k Rule #2: If |something| > k, then EITHER something > k OR something < -k Target question: Is x > 0 ? Statement 1: |x+3| < ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to In the xy-plane, what is the y-intercept of line l? in the Data Sufficiency forum
“Target question: What is the y-intercept of line L? IMPORTANT: When I scan the two statements, I see that they are strongly related. If the x-intercept is -1/3 (as per statement 2), the slope of the line is GUARANTEED to be 3 times its y-intercept (as per statement 1). Here''s why... ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to At garage sale, all of the prices of the items sold were in the Problem Solving forum
“The price of the radio was the 15th highest price So, there were 14 items that were more expensive than the radio. In other words, if we listed all of the prices in ascending order, we''d get something like: ........... radio, X, X, X, X, X, X, X, X, X, X, X, X, X, X The price of the radio ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to A certain company charges $6 per package to ship packages in the Problem Solving forum
“Let x = the weight of the package (in pounds) So, the shipping cost = $6 + 2x We''re told the shipping cost is $38. So, we can write: 6 + 2x = 38 Subtract 6 from both sides: 2x = 32 Solve: x = 32/2 = 16 Answer: A Cheers, Brent”
December 19, 2018
Brent@GMATPrepNow posted a reply to Is x/y>1? in the Data Sufficiency forum
“Target question: Is x/y > 1? Statement 1: x > y Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 3 and y = 1. In this case, x/y = 3/1 = 3. So, the answer to the target question is YES, x/y IS greater than 1 Case b: x = ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to How many 4-digit numbers greater than 3,000 have the digits: in the Problem Solving forum
“Take the task of creating 4-digit numbers and break it into stages. We’ll begin with the most restrictive stage. Stage 1: Select the first digit (to go in the thousands place) Since the 4-digit number must be GREATER THAN 3000, the first digit must be greater than or equal to 3 This means ...”
December 19, 2018
GMATGuruNY posted a reply to At garage sale, all of the prices of the items sold were in the Problem Solving forum
“Since the radio = 15th highest price, 14 prices are HIGHER: RADIO-----14 higher prices-----> Since the radio = the 20th lowest price, 19 prices are LOWER: <-----19 lower prices-----RADIO-----14 higher prices----> Total number of items = 19 + RADIO + 14 = 34. The correct answer is ...”
December 19, 2018
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Shortcut for quickly dividing by 5 in your head Video: https://www.youtube.com/watch?v=fK29jTSJOi8 Cheers, Brent”
December 18, 2018
Brent@GMATPrepNow posted a reply to At a certain university, the ratio of the number of teaching in the Problem Solving forum
“We can solve this using equivalent ratios We''re comparing teaching assistants/number of students Let x = number of students possible We can write: 5/x = 3/80 Cross multiply to get: 3x = (5)(80) Simplify: 3x = 400 Solve: x = 400/3 = 133 1/3 = 133.3333 Since 134 students would exceed ...”
December 18, 2018
Brent@GMATPrepNow posted a reply to Automobile A is traveling at two-thirds the speed that in the Data Sufficiency forum
“ Given: Automobile A is traveling at two-thirds the speed that Automobile B is traveling. Let A = Car A''s speed Let B = Car B''s speed So, we can write: A = (2/3)B Target question: What is the value of A? Statement 1: If both automobiles increased their speed by 10 miles per hour, ...”
December 18, 2018
GMATGuruNY posted a reply to x and y are positive integers. Is y an even integer? in the Data Sufficiency forum
“The product of two consecutive integers is always EVEN: 1*2 = 2 2*3 = 6 3*4 = 12 Statement 1: y+2 = x² + x y+2 = x(x+1) y+2 = product of 2 consecutive integers y+2 = EVEN y = EVEN - 2 y = EVEN - EVEN y = EVEN SUFFICIENT. Statement 2: No information about y. INSUFFICIENT. The ...”
December 18, 2018
GMATGuruNY posted a reply to (0.0004)(0.000005)/200,000 is equal to which of the followin in the Problem Solving forum
“I believe that the answer choices should appear as shown below: The blue values below cancel out, leaving only the red values: (4 * 10¯⁴)(5 * 10¯⁶) / (20 * 10⁴) = 10¯¹⁰/10⁴ = 10¯¹⁴. The correct answer is B.”
December 18, 2018
GMATGuruNY posted a reply to Sanjana jogged uphill for a while at an average speed of 3 m in the Problem Solving forum
“This is a MIXTURE problem. Two speeds (3 mph and 8 mph) are combined to form a mixture with an average speed of 4 mph. To determine how much time must be spent at each speed, we can use ALLIGATION. Let U = the uphill speed and D = the downhill speed. Step 1: Plot the 3 speeds on a number ...”
December 18, 2018
Brent@GMATPrepNow posted a reply to If every boy in a kindergarten class buys a soda and every g in the Problem Solving forum
“Let B = # of boys in kindergarten Let G = # of girls in kindergarten Let J = price (in CENTS) of ONE juice box Let S = price (in CENTS) of ONE soda If every boy in a kindergarten class buys a soda and every girl in the same class buys a juice box, the class will spend 1¢ less in total than it ...”
December 17, 2018
Brent@GMATPrepNow posted a reply to Sanjana jogged uphill for a while at an average speed of 3 m in the Problem Solving forum
“You could also try testing the answer choices. Cheers, Brent”
December 17, 2018
Brent@GMATPrepNow posted a reply to If 3x + 12 = 21, then x + 4 = A. 3 B. 4 C. 5 D. 7 E. 9 in the Problem Solving forum
“One option is to first solve the equation, 3x + 12 = 21, for x, and then determine the value of x+4. Alternatively, we can factor the left side to get: 3(x + 4) = 21 Now divide both sides by 3 to get: x + 4 = 7 Answer: D Cheers, Brent”
December 17, 2018
Brent@GMATPrepNow posted a reply to If a, b & c are integers, is abc odd? in the Data Sufficiency forum
“Some important rules: #1. (ODD)(ODD) = ODD #2. (ODD)(EVEN) = EVEN #3. (EVEN)(EVEN) = EVEN Given: a, b & c are integers Target question: Is abc odd? Statement 1: ab is odd This tells us that a and b are both odd. However, we have no information about c. Consider these two ...”
December 17, 2018
Brent@GMATPrepNow posted a reply to In the coordinate plane, the y-intercept of the line k is eq in the Problem Solving forum
“One approach is to choose some values that meet the given information. In the coordinate plane, the y-intercept of the line k is equal to twice its slope. Okay, so let''s say the y-intercept of line k is 6. We get: https://i.imgur.com/qJ5GeRQ.png Since the y-intercept (6) is TWICE the ...”
December 17, 2018
GMATGuruNY posted a reply to If 2 and 17 are factors of positive integer n, then which of in the Problem Solving forum
“2 and 17 have no factors in common. Since n must be divisible by both 2 and 17 -- and 2*17 = 34 -- n must be a MULTIPLE OF 34. Thus, n must be divisible by I. Eliminate any answer choice that does not include I. Eliminate B and E. If n=34, then n is not divisible by II or III. Eliminate any ...”
December 17, 2018
GMATGuruNY posted a reply to Seven students are trying out for the school soccer team, on in the Problem Solving forum
“To keep track of the number of options for each position, draw a TREE. Start with the MOST RESTRICTED position, which is SWEEPER. If Sweeper = 3, then Goalie = 5. If Sweeper = 4, then Fullback = 2. Here''s the tree so far: http://s11.postimage.org/laxnlsbof/soccer_half_tree.jpg Now complete ...”
December 17, 2018
Brent@GMATPrepNow posted a reply to Sanjana jogged uphill for a while at an average speed of 3 m in the Problem Solving forum
“Let''s start with a "Word Equation" (distance traveled uphill) + (distance traveled downhill) = TOTAL DISTANCE Let t = the time spent jogging UPHILL (in hours) The total travel time = 40 minutes = 2/3 HOURS So, 2/3 - t = the time spent jogging DOWNHILL (in hours) Distance = ...”
December 16, 2018
Brent@GMATPrepNow posted a reply to If one manual weighs 400 grams, how many kilograms does a in the Problem Solving forum
“Since the answer choices are VERY SPREAD APART, we can be quite aggressive with our ESTIMATION. (400 grams)(50 manuals) = 20,000 grams = 20 KILOgrams So, the answer is approximately 20 Answer: C Cheers, Brent”
December 16, 2018
GMATGuruNY posted a reply to In a network of car dealerships, a group of d sales director in the Data Sufficiency forum
“A group...EACH has a team. The wording above does not convey a logical meaning. When each serves as an adverb, it cannot refer to a singular noun such as a group. When each serves as an adverb, it may refer only to a PLURAL noun. The prompt seems intended to convey the following: Since ...”
December 16, 2018
GMATGuruNY posted a reply to If one manual weighs 400 grams, how many kilograms does a in the Problem Solving forum
“48 manuals * (400 grams)/(1 manual) * (1 kilogram)/(1000 grams) = (48*400)/1000 = 192/10 = 19.2 kilograms.”
December 16, 2018
GMATGuruNY posted a reply to When the positive integer x is divided by 9, the remainder in the Problem Solving forum
“Let x=5, since dividing 5 by 9 yields a remainder of 5: 5/9 = 0 R5. When 3x=15 is divided by 9, we get: 15/9 = 1 R6. The correct answer is E.”
December 16, 2018
GMATGuruNY posted a reply to The main ingredient in a certain prescription drug capsule in the Problem Solving forum
“Each capsule contains 600 milligrams of ingredient. 10⁶ milligrams = 1 kilogram. 1 kilogram of ingredient = 500 dollars. To determine the cost per capsule, we must use the relationships above to convert 600 milligrams into dollars: (600 milligrams) * (1 kilogram)/(10⁶ milligrams) * (500 ...”
December 15, 2018
GMATGuruNY posted a reply to Each Machine of type A has 3 steel parts and 2 chrome parts. in the Problem Solving forum
“(3 steel parts in each type A machine) + (4 steel parts in each type B machine) = 20 steel parts: 3A + 4B = 20 3A = a multiple of 3 less than 20. Options for 3A: 3, 6, 9, 12, 15, 18 4B = a multiple of 4 less than 20. Options for 4B: 4, 8, 12, 16 Only the two values in blue yield a sum ...”
December 15, 2018
Brent@GMATPrepNow posted a reply to Madge paid A dollars for R bananas. Dean paid B dollars for in the Data Sufficiency forum
“ Given: Madge paid A dollars for R bananas. Dean paid B dollars for S bananas. Target question: Which one of them paid a higher price-per-banana? Statement 1: B > A This tells us that Dean PAID more than Madge paid. However, we don''t know HOW MANY bananas each person bought. ...”
December 15, 2018
Brent@GMATPrepNow posted a reply to Jason's salary and Karen's salary were each p percent in the Data Sufficiency forum
“Target question: What is the value of p? Given: Jason''s salary and Karen''s salary were each p percent greater in 1998 than in 1995. IMPORTANT: If my 1998 salary is p percent greater than my 1995 salary, then: 1998 salary = (1 + p/100)(1995 salary) For example, if my 1998 salary is 7 percent ...”
December 15, 2018
Brent@GMATPrepNow posted a reply to If w + 2x = 150, 2w + 3y = 100, and x + 3z = 50, what is the in the Problem Solving forum
“GIVEN: w + 2x = 150 2w + 3y = 100 x + 3z = 50 If we add all 3 equations, we get: 3w + 3x + 3y + 3z = 300 Divide both sides by 3 to get: w + x + y + z = 100 Answer: D Cheers, Brent”
December 15, 2018
GMATGuruNY posted a reply to Did Jeff record more sales revenue this month than Dan did? in the Data Sufficiency forum
“Statement 1: For every $100 commission that Dan earns, Jeff earns $120 in commission. Since the commission rates for Dan and Jeff are unknown, no way to determine whether Jeff recorded more sales revenue than Dan. INSUFFICIENT. Statement 2: Since Jeff''s sales and Dan''s sales can be any ...”
December 14, 2018
GMATGuruNY posted a reply to If sets A and B have the same number of terms, is the standa in the Data Sufficiency forum
“Standard deviation describes how much the values in a set deviate from the mean. A larger standard deviation indicates that the values are deviating more -- getting farther away from -- the mean. So the question can be rephrased: Do the values in set A deviate more from the mean than the do ...”
December 14, 2018
GMATGuruNY posted a reply to Is (y−10)^2>(x+10)^2? ----Veritas in the Data Sufficiency forum
“x² < y² can be rephrased as follows: |x| < |y| Thus, the question stem can be rephrased as follows: Is |x+10| < |y-10|? |a-b| = the distance between a and b |a+b| = |a-(-b)| = the distance between a and -b Thus, the question stem can be further rephrased as follows: Is the ...”
December 14, 2018
Brent@GMATPrepNow posted a reply to If A is the center of the circle shown above and AB = BC in the Problem Solving forum
“First recognize that all radii (indicated with BLUE lines) have equal length https://i.imgur.com/iz8ur0Z.png Since BC and CD are both equal to the radius AB, we can see that all BLUE lines have equal length https://i.imgur.com/mF0UxTp.png This means the 2 blue triangles are EQUILATERAL ...”
December 13, 2018
GMATGuruNY posted a reply to Three congruent circles overlap in such a way that each circ in the Problem Solving forum
“The statement above is incorrect. https://i.postimg.cc/jL1NMjTL/three-congruent-circles-shaded-region.png The shaded region encompassing the equilateral triangle is not a circle.”
December 13, 2018
Brent@GMATPrepNow posted a reply to If m and n are positive integers, is mn an even number? in the Data Sufficiency forum
“Some important rules: #1. ODD +/- ODD = EVEN #2. ODD +/- EVEN = ODD #3. EVEN +/- EVEN = EVEN #4. (ODD)(ODD) = ODD #5. (ODD)(EVEN) = EVEN #6. (EVEN)(EVEN) = EVEN Target question: Is mn an even number? Given: m and n are positive integers Statement 1: m/n is an even number. ...”
December 13, 2018
Brent@GMATPrepNow posted a reply to What distance did Jane travel? in the Data Sufficiency forum
“Target question: What distance did Jane travel? Statement 1: Bill traveled 40 miles in 40 minutes. No info about Jane Statement 1 is NOT SUFFICIENT Statement 2: Jane traveled at the same average rate as Bill We don''t know Bill''s speed (rate) Statement 2 is NOT SUFFICIENT ...”
December 13, 2018
GMATGuruNY posted a reply to Three congruent circles overlap in such a way that each circ in the Problem Solving forum
“Area of an equilateral triangle = (s²/4)√3. √3 ≈ 1.7. https://i.postimg.cc/1gCbnSTK/three-congruent-circles.png Each circle has a radius of 8, yielding the equilateral triangle above. Area of the equilateral triangle = (8²/4)√3 = 16√3 ≈ (16)(1.7) = 27. The three circles form ...”
December 13, 2018
Brent@GMATPrepNow posted a reply to If Mike buys a biclycle and a helmet for a total cost of in the Data Sufficiency forum
“Target question: How much does the helmet cost? Given: bicycle + helmet = $315 Statement 1: The bicycle costs twice as much as the helmet. Let x = cost of helmet So, 2x = cost of bicycle Since the total cost is $315, we can write: x + 2x = 315 Simplify: 3x = 315 Solve: x = 315/3 = ...”
December 13, 2018
Brent@GMATPrepNow posted a reply to In isosceles triangle DEF, what is the measure of angle E? in the Data Sufficiency forum
“Target question: What is the measure of ∠E? Given: Triangle DEF is an ISOSCELES triangle This tells us that there are 2 equal angles Statement 1: ∠D measures 42 degrees Here it''s hard to tell whether there''s a second 42-degree angle or whether the other two angles are different. ...”
December 12, 2018
Brent@GMATPrepNow posted a reply to Ramon wants to cut a rectangular board into identical square in the Problem Solving forum
“If we aren''t wasting any wood, the length and width must be divisible by one side of the square So, this question is a clever way of asking us what the greatest common divisor (GCD) of 18 and 30 The GCD of 18 and 30 is 6, so if we cut squares that are 6 x 6, then we won''t waste any wood. We ...”
December 12, 2018
ceilidh.erickson posted a reply to GMAT Experience - Looking for advice in the I just Beat The GMAT! forum
“Your scores have been pretty inconsistent, with both quant & verbal fluctuating a lot. Given that, a 660 result is not surprising. Inconsistency on quant almost always indicates CARELESS ERRORS or sloppy technique - sometimes you get lucky, sometimes you don''t. A lot of students brush off ...”
December 12, 2018
ceilidh.erickson posted a reply to 660 GMAT - What are my odds? in the The Application Process forum
“It really depends on where you''re applying, and how much you stand out against other applicants in the pool. For example, applicants from France might be underrepresented in certain pools, as opposed to applicants from other countries. I''d recommend doing free consultations with any admissions ...”
December 12, 2018
ceilidh.erickson posted a reply to Test day in the GMAT Strategy forum
“For anyone else with questions about test day & scores, here''s an article I wrote: https://www.manhattanprep.com/gmat/blog/scheduling-your-gmat-everything-you-need-to-know-about-booking-cancelling-reporting-etc/”
December 12, 2018
Brent@GMATPrepNow posted a reply to How many perfect squares lie between 2^4 and 2^8, inclusive? in the Problem Solving forum
“First rewrite 2^4 and 2^8 as SQUARES of integers (aka perfect squares) 2^4 = (2²)² = 4² 2^8 = (2^4)² = 16² So, we want to find the number of perfect squares FROM 4² to 16² inclusive Let''s list them: 4², 5², 6², 7², 8², 9², 10², 11², 12², 13², 14², 15², and 16² There are ...”
December 12, 2018
Brent@GMATPrepNow posted a reply to If 5x + 3y = 17, what is the value of x? in the Data Sufficiency forum
“Target question: What is the value of x? Given: 5x + 3y = 17 Statement 1: x is a positive integer Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = 4 (these values satisfy the given equation, 5x + 3y = 17). In ...”
December 12, 2018
GMATGuruNY posted a reply to A baseball team’s season consists of playing 162 games. At in the Problem Solving forum
“The team has won 58 percent of the games it has played. 58% = 58/100 = 29/50. The fraction in blue implies that the number of wins must be a MULTIPLE OF 29: If 50 games are played, the number of wins = (29/50)(50) = 29. If 100 games are played, the number of wins = (29/50)(100) = 58. If 150 ...”
December 12, 2018
GMATGuruNY posted a reply to Effect of several Tsunamis in the Sentence Correction forum
“A method is a PROCEDURE for accomplishing a particular goal. Since the clause in red does not discuss a procedure, it cannot be summed up as a METHOD.”
December 11, 2018
GMATGuruNY posted a reply to Effect of several Tsunamis in the Sentence Correction forum
“The SC above is modeled -- not altogether successfully -- after SC30 in the OG12: https://www.beatthegmat.com/not-sure-about-the-answer-of-a-question-from-og12-t265701.html Rather than study the SC above, stick to the official SC.”
December 11, 2018
GMATGuruNY posted a reply to The table above shows the number of students in three clubs in the Problem Solving forum
“The values in the chart DOUBLE-COUNT any student who belongs to 2 of the 3 clubs. The totals for chess and drama -- 40 and 30 -- double-count the 10 students who belong to both chess AND drama. The totals for chess and math -- 40 and 25 -- double-count the 5 students who belong to both chess AND ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to How many integers between 324,700 and 458,600 have tens in the Problem Solving forum
“We want to determine how many integers end in 13 For example, 324713, 324813, 324913, 325013, . . . etc. Recognize that, for every 100 consecutive integers, only 1 will end in 13. There are 133,900 integers between 324,700 and 458,600 (since 458,600 - 324,700 = 133,900) Of those 133,900 ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to The quadrilateral ABCD is a square with sides of length 12. in the Problem Solving forum
“This question could take a while to answer (especially if you don''t know where to begin! :-). Fortunately, we can take advantage of an IMPORTANT feature about geometric diagrams on the GMAT: The diagrams in GMAT problem solving questions are DRAWN TO SCALE unless stated otherwise. We have ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to A palindrome is a number that reads the same forward and in the Problem Solving forum
“Take the task of building palindromes and break it into stages. Stage 1: Select the ten-thousands digit We can choose 1, 2, or 3 So, we can complete stage 1 in 3 ways Stage 2: Select the thousands digit We can choose 1, 2, or 3 So, we can complete stage 2 in 3 ways Stage 3: Select ...”
December 11, 2018
GMATGuruNY posted a reply to This year, a woman has a lucrative one-year position. During in the Problem Solving forum
“Let r=9, with the result that 1+r = 10. Her husband can turn each dollar she gives him into 1+r, which will be deposited in a bank account. Let the wife give the husband $1, implying that the husband turns this $1 into 1+r = $10. Thus, the amount deposited into the account = $10. The ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to This year, a woman has a lucrative one-year position. During in the Problem Solving forum
“Let T = the woman''s total salary for the year During this year, she will give a fraction f of her salary to her husband, a private investor, to invest and they will live this year on the remainder. So, the amount SAVED (and then given to huspand)= fT This means the amount SPENT = T - fT ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to A frog is climbing a greasy pole. The frog can climb 2 in the Problem Solving forum
“Let''s solve this by making table Time elapsed | height 1 hours | 4 cm 2 hours | 8 cm REST (slide) 2.5 hours | 7 cm 3.5 hours | 11 cm 4.5 hours | 15 cm REST (slide) 5 hours | 14 cm 6 hours | 18 cm 7 hours | 22 cm REST (slide) 7.5 hours | 21 cm 8.5 hours | 25 cm 9.5 hours | 29 cm ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to Oil, vinegar, and water are mixed in a 3 to 2 to 1 ratio to in the Problem Solving forum
“GIVEN: oil: vinegar : water = 3 : 2 : 1 Let''s first try to use ALL 8 cups of oil Take 3 : 2 : 1 and multiply all 3 parts by 8/3 to get the EQUIVALENT ratio 8 : 16/3 : 8/3 Simplify to get: 8 : 5 1/3 : 2 2/3 So, in this case, the dressing is comprised of 8 cups of oil, 5 1/3 cups of vinegar, ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to Line DB divides Rectangle ABCD into two equal triangles. Is in the Data Sufficiency forum
“IF all 4 sides of the rectangle have EQUAL length (i.e,, the shape is a square), then the diagonal will create two 45-45-90 right triangles. However, if the sides are not all the same length, the resulting triangles will NOT be 45-45-90 right triangles. Cheers, Brent”
December 10, 2018
GMATGuruNY posted a reply to Line DB divides Rectangle ABCD into two equal triangles. Is in the Data Sufficiency forum
“Yes, the line will be a diagonal, but the four angles created by this diagonal will each be 45 degrees only if the rectangle is a square.”
December 10, 2018
Brent@GMATPrepNow posted a reply to A father distributed his total wealth to his two sons. How in the Data Sufficiency forum
“ Given: A father distributed his total wealth to his two sons. Target question: How much wealth did the father have? Statement 1: The elder son received 3/5 of the wealth. Without any dollar values, there''s no way to answer the target question with certainty. So, statement 1 is NOT ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to At what speed was Erik running when he was at the halfway po in the Data Sufficiency forum
“IMPORTANT: The two statements essentially provide the exact same information. If it took Erik 2 hours to travel 10 miles, we can conclude that his average speed was 5 miles per hour. When the two statements provide the same information in a Data Sufficiency question, the correct answer must be ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to [x] is the greatest integer less than or equal to x. What is in the Data Sufficiency forum
“Here are a few similar questions to practice with: - https://www.beatthegmat.com/if-is-the-greatest-integer-less-than-or-equal-to-x-what-t302459.html - https://www.beatthegmat.com/g-x-is-the-greatest-integer-less-than-or-equal-to-x-t298237.html - ...”
December 10, 2018
GMATGuruNY posted a reply to What is the solution set of (1+|x|)(1+x) > 0? in the Problem Solving forum
“x=0 satisfies (1+|x|)(1+x) > 0. Since x=0 is not included in B, C, D or E, eliminate B, C, D and E. The correct answer is A.”
December 10, 2018
GMATGuruNY posted a reply to Tom drives from town A to town B, driving at a constant spee in the Problem Solving forum
“Let the distance between A and B = 120 miles. Since the 120-mile distance between A and B is twice the distance between B and C, the distance between B and C = 60 miles, implying that the total distance = 120+60 = 180 miles. Since the average speed for the 120-mile leg between A and B = 60 ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to When 6 is multiplied by x, the result is the same as when x in the Problem Solving forum
“When 6 is multiplied by x, the result is the same as when x is added to 9 In other words: 6x = 9 + x Subtract x from both sides: 5x = 9 Divide both sides by 5 to get: x = 9/5 Answer: E Cheers, Brent”
December 9, 2018
Brent@GMATPrepNow posted a reply to Three photographers, Lisa, Mike and Norm, take photos of a w in the Problem Solving forum
“We can also solve the question using 1 variable Norms photos number 10 more than twice the number of Lisa''s photos Let x = the number of photographs that Lisa took. So, 2x + 10 = the number of photographs that Norm took. The total of Lisa and Mikes photos is 50 less than the sum of ...”
December 9, 2018
Brent@GMATPrepNow posted a reply to At a certain factory, each employee working the second shift in the Problem Solving forum
“Let''s assign a "nice" value to the number of widgets made by ONE employee. We''ll also assign a nice value to the number of employees on each shift. At a certain factory, each employee working the SECOND shift produced 2/3 as many widgets as each employee working the FIRST shift. ...”
December 9, 2018
GMATGuruNY posted a reply to If the average (arithmetic mean) of five consecutive negativ in the Problem Solving forum
“The value of k is irrelevant. For any set of 5 consecutive integers, the difference between the greatest and least will always be 4. The correct answer is A.”
December 9, 2018
GMATGuruNY posted a reply to Three photographers, Lisa, Mike and Norm, take photos of a w in the Problem Solving forum
“The sum for Lisa and Mike is 50 less than the sum for Norm and Mike. Since Mike is common to both sums, the 50-photo difference must be yielded solely by Lisa and Norm. Implication: Lisa took 50 fewer photos than Norm. We can PLUG IN THE ANSWERS, which represent the number of photos taken ...”
December 9, 2018
GMATGuruNY posted a reply to Andrew sells vintage clothing at a flea market at which he in the Problem Solving forum
“Let h=3. Since an average of $78 is sold per hour, the total revenue for 3 hours = 3*78 = 234. Since the cost for the day is composed of $150 for the table rental and $10 per hour for the assistant, the cost for the day = 150 + 3*10 = 180. P = profit = revenue - cost = 234 - 180 = 54. The ...”
December 9, 2018
GMATGuruNY posted a reply to OG2019 -Logical flow in the Critical Reasoning forum
“It takes for granted that X implies that X is an ASSUMPTION: a statement that must be true for the conclusion to hold. Thus, when X is negated, the conclusion must be invalidated. B: It takes for granted that the volunteers with the highest levels of self-esteem had better social skills than did ...”
December 8, 2018
GMATGuruNY posted a reply to OG2019 -Logical flow in the Critical Reasoning forum
“Premise: Volunteers with the highest levels of self-esteem consistently rated themselves as having much better social skills than did the volunteers with moderate levels. Conclusion: Attaining an exceptionally high level of self-esteem greatly improves one’s social skills. The correct answer ...”
December 8, 2018
Brent@GMATPrepNow posted a reply to If two of the four expressions x+y, x+5y, x-y, and 5x-y are in the Problem Solving forum
“Okay, first recognize that x² - (by)² is a DIFFERENCE OF SQUARES. Here are some examples of differences of squares: x² - 25y² 4x² - 9y² 49m² - 100k² In general, we can factor differences of squares as follows: a² - b² = (a-b)(a+b) So . . . x² - 25y² = (x+5y)(x-5y) 4x² - ...”
December 8, 2018
ceilidh.erickson posted a reply to If all of the telephone extensions in a certain company must in the Problem Solving forum
“Here is yet another solution: Most of the time when we''re arranging n things (people in a line, letter combinations, etc) with a diminishing pool (i.e. we can''t use the same item twice), the number of arrangements is simply n!. If we could arrange these 4 numbers into extensions without any ...”
December 7, 2018
ceilidh.erickson posted a reply to Arthmetic subsequent value Problem Solving question in the Problem Solving forum
“If each row had 2 more spaces than the previous, we could imagine this as CONSECUTIVE SUM formula: sum = (average)(# of terms) The average of a consecutive set = the average of the endpoints --> (biggest + smallest)/2 The # of terms = the difference between the biggest and the smallest, divided ...”
December 7, 2018
ceilidh.erickson posted a reply to Goronian lawmaker: Goronia's Cheese Importation Board, the a in the Critical Reasoning forum
“For more on this YES / NO test for EVALUATE questions, see: https://www.beatthegmat.com/guitar-strings-often-go-dead-become-less-respon-t304393.html#820897 https://www.beatthegmat.com/because-of-a-rare-type-of-fungus-that-killed-off-many-cacao-t304283.html#820187”
December 7, 2018
ceilidh.erickson posted a reply to Goronian lawmaker: Goronia's Cheese Importation Board, the a in the Critical Reasoning forum
“When we''re asked to EVALUATE an argument, we need to establish the conclusion of the argument and its supporting premises. We then need to determine what information is MISSING. Premises: - Goronia''s Cheese Importation Board rejects about one percent of the cheese that it inspects. - the ...”
December 7, 2018
ceilidh.erickson posted a reply to 700-800 Level Questions in the GMAT Math forum
“If you''re looking for ultra-difficult problems to practice with, I recommend checking out the Manhattan Prep Advanced Quant guide. (Forgive the plug. As yet, there''s no easy way to access OG problems by difficulty level). This book contains strategies that specifically pertain to high-level ...”
December 7, 2018
Brent@GMATPrepNow posted a new topic called CHALLENGE: What is the value of k? in the Data Sufficiency forum
“What is the value of k? $$(1) k^2-5k-66=0$$ $$(2) \frac{2k}{k^2+5k}=\frac{1}{8}$$ Source: www.gmatprepnow.com Answer: B Estimated difficulty level: 600-650”
December 7, 2018
ceilidh.erickson posted a reply to Economist: On average, the emergency treatment for an elderl in the Critical Reasoning forum
“This argument style is very common on the GMAT: it compares 2 things (cost of emergency care v. cost of therapeutic program) but fails to take into account any other factors. Here are some other CR questions with similar logical flaws: ...”
December 7, 2018
ceilidh.erickson posted a reply to Economist: On average, the emergency treatment for an elderl in the Critical Reasoning forum
“To WEAKEN an argument, we must first find the logical flaws / unstated assumptions in the argument. Premises: - On average, the emergency treatment for an elderly person for injuries resulting from a fall costs $11,000. - A new therapeutic program can significantly reduce an elderly person''s ...”
December 7, 2018
ceilidh.erickson posted a reply to OG 2018 Difficulty level for questions? in the GMAT Math forum
“GMAC has not published difficulty levels for any of the OGs up to OG 2018. Prep companies can only take our best guesses at the difficulty levels, based on the performances of our students. Manhattan Prep has a tool called Navigator that allows students to record their answers to every OG ...”
December 7, 2018
Brent@GMATPrepNow posted a reply to Circle question help in the Problem Solving forum
“We''ll begin by arbitrarily placing point A somewhere on the circumference. https://i.imgur.com/hRHtq4o.png So, we want to know the probability that a randomly-placed point B will yield a chord AB that is at least 2 cm long. So, let''s first find a location for point B that creates a chord ...”
December 7, 2018
Brent@GMATPrepNow posted a reply to Let C be defined as the sum of all prime numbers between in the Problem Solving forum
“C = 2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 = 129 So, C/3 = 129/3 = 43 Answer: E Cheers, Brent”
December 7, 2018
Brent@GMATPrepNow posted a reply to 2k years ago Frank was 3k years old. In k years Frank's age, in the Problem Solving forum
“These kinds of questions (Variables in the Answer Choices - VIACs) can be answered algebraically or using the input-output approach. Mitch has solved the question using the input-output approach, so let''s use the algebraic approach. 2k years ago Frank was 3k years old. We''re given Frank''s ...”
December 7, 2018
GMATGuruNY posted a reply to 2k years ago Frank was 3k years old. In k years Frank's age, in the Problem Solving forum
“Let k=10. 2k years ago Frank was 3k years old. Since k=10, 20 years ago Frank was 30 years old, implying that his age now = 30+20 = 50. In k years Frank''s age, in years, will be: Since Frank is now 50 years old, Frank''s age in 10 years = 50+10 = 60. The correct answer must yield a value ...”
December 7, 2018
GMATGuruNY posted a reply to Which of the following equations is satisfied by x=1+√2? in the Problem Solving forum
“Alternate approach: For any quadratic in the form x² + bx + c = 0, where b and c are rational numbers: If one of the roots is m+√n, then the other root is m-√n. Sum of the roots = -b Product of the roots = c Here, since one of the roots is 1+√2, the other root is 1-√2. Thus: -b ...”
December 7, 2018
Brent@GMATPrepNow posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum
“In order to minimize the number of homeowners, we must MAXIMIZE the number of men in the group, since the proportion of male homeowners (20%) is less than the proportion of female homeowners (25%) So, let''s see what happens if there are 199 men and 1 woman. If 20% (aka 1/5) of the men are ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to If all of the telephone extensions in a certain company must in the Problem Solving forum
“NOTE: Always SCAN the answer choices before performing any calculations. Here, we notice that the answer choices are pretty small, so if we don''t come up a full solution, we should consider LISTING AND COUNTING We get the following extensions: 1236 1326 1362 1632 2136 2316 3126 3162 ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to If all of the telephone extensions in a certain company must in the Problem Solving forum
“Take the task of arranging the 4 digits and break it into stages. We’ll begin with the most restrictive stage. Stage 1: Select the digit in the units position Since the 4-digit extension must be EVEN, the unit digit must be either 2 or 6 So, we can complete stage 1 in 2 ways Stage ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to What was the revenue that a theater received from the sale in the Data Sufficiency forum
“Target question: What was the revenue that a theater received from the sale of 400 tickets Jump straight to . . . Statements 1 and 2 combined The combined statements tell us that 100 tickets sold for the full price of $25 each. The remaining 300 tickets were sold at some reduced price. ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to A certain high school offers two foreign languages, Spanish in the Problem Solving forum
“Another approach is to use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of students, and the two characteristics are: - ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to In year x, it rained on 40% of all Mondays and 20% of all in the Data Sufficiency forum
“In any given year, there will be 52 or 53 Mondays, 52 or 53 Tuesdays, etc. So, it''s impossible to say that it rained on 40% of all Mondays or 20% of all Tuesdays, etc. For example, if there are 52 Mondays, then 40% of 52 = 20.8, which means that it rained on 20.8 days (impossible). Cheers, ...”
December 6, 2018
GMATGuruNY posted a reply to Each day at Dan’s new job, he earns $10 more than the day in the Data Sufficiency forum
“Since each payday is $10 more than the preceding payday, the list of 15 paydays constitutes an EVENLY SPACED SET. Statement 1: For any evenly spaced set: Median = Sum/Quantity. Thus: Pay on the 14th day = median of the 3 most recent days = sum/quantity = 690/3 = 330. Since the pay on the ...”
December 6, 2018
GMATGuruNY posted a reply to Tom saved $10,000 at a constant compound interest rate of r in the Problem Solving forum
“Original deposit: 10,000. The balance doubles every 10 years. After 10 years, we get: 2*10,000 = 20,000. After 20 years, we get: 2*20,000 = 40,000. After 30 years, we get: 2*40,000 = 80,000. The correct answer is E.”
December 6, 2018
GMATGuruNY posted a reply to If a, b, and c are positive integers such that a < b < in the Data Sufficiency forum
“Does (a/100) * (b/100) * c = integer? Test integer values such that a < b < c. Statement 1: b = (a/100)¯¹ Thus, b = 100/a. Test the smallest possible value for a. Case 1: a=1 Here, b =100/1 = 100. In this case, (a/100) * (b/100) * c = 1/100 * 100/100 * c = c/100. If c ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to Three men sit at a table. One dollar is placed in front of in the Problem Solving forum
“Let''s see what happens if a man waits until the last (5th) round to take the money. Round #1: $1 placed in front of the man (but he doesn''t take it) Round #2: Now, $2 placed in front of the man (but he doesn''t take it) Round #3: Now, $4 placed in front of the man (but he doesn''t take it) ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to If a, b, and c are positive integers such that a < b < in the Data Sufficiency forum
“Target question: Is a% of b% of c an integer? This is a great candidate for rephrasing the target question. Aside: We have a free video with tips on rephrasing the target question: a% of b% of c is the same as (a/100)(b/100)(c), which equals abc/10,000 So, we can rephrase the target ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to If w, x, and y are consecutive odd positive integers and w & in the Problem Solving forum
“Here''s a 3rd approach: GIVEN: w, x, and y are consecutive odd positive integers and w < x < y Since consecutive odd integers go up by 2, we can write: x = w + 2, and y = w + 2 + 2 = w + 4 So, y - x - w = (w + 4) - (w + 2) - w = w + 4 - w - 2 - w = 2 - w Since w is an ODD integer, ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to What is the difference between the number of three-member in the Problem Solving forum
“The number of three-member committees that can be formed from a group of nine members Since the order in which we select the 3 people does not matter, we can use combinations. We can choose 3 people from 9 people in 9C3 ways 9C3 = (9)(8)(7)/(3)(2)(1) = 84 three-member committees The total ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to All the 7 books of the fictional character series Horry in the Problem Solving forum
“At $8 per book, the 8 books SHOULD have cost $64 (8 x $8 = $64) However, Harry bought the 8 books for $60 So, the amount Harry saved = $64 - $60 = $4 What is savings percentage for Harry, who bought the whole set together? Percent savings = 100(amount saved)/(original price) = 100(4)/64 = ...”
December 5, 2018
GMATGuruNY posted a reply to If a, b, and c are positive integers, what is the remainder in the Data Sufficiency forum
“Statement 1: No information about b. INSUFFICIENT. Statement 2: No information about a. INSUFFICIENT. Statements combined: Case 1: c=3, with the result that a=3³=27 and that b=(3-2)³=1 In this case, a-b = 27-1 = 26. Dividing 26 by 6, we get: 26/6 = 4 R2 Case 2: c=4, with the ...”
December 5, 2018
GMATGuruNY posted a reply to If w, x, and y are consecutive odd positive integers and w & in the Problem Solving forum
“Test easy cases: 5-3-1 = 1 7-5-3 = -1 The case in green indicates that -1 is a possible value of y-x-w. The correct answer is C.”
December 5, 2018
GMATGuruNY posted a reply to x is a positive number. What is the median of x, √x and x^ in the Data Sufficiency forum
“To determine the median of x, √x and x², we need to know the value of x. Statement 1: Since x is positive, we can safely divide both sides by x: x²/x = x/x x = 1 SUFFICIENT. Statement 2: x² + x + 1 = 3x x² - 2x + 1 = 0 (x-1)² = 0 x = 1 SUFFICIENT. The correct answer is D.”
December 5, 2018
GMATGuruNY posted a reply to A triangle is formed by connecting three randomly chosen ver in the Problem Solving forum
“Let the 6 vertices = A, B, C, D, E and F. P(the triangle includes AT LEAST 1 side of the hexagon) = 1 - P(the triangle includes NO sides of the hexagon). From the 6 vertices, the number of ways to choose 3 to form a triangle = 6C3 = (6*5*4)/(3*2*1) = 20. Of these 20 triangles, only 2 include ...”
December 5, 2018
GMATGuruNY posted a reply to Working together, Machine A and Machine B can produce a in the Data Sufficiency forum
“Since A+B take 4 hours to produce 200 widgets, the combined rate for A+B = w/t = 200/4 = 50 widgets per hour. To determine A''s time to produce 200 widgets, we need to know A''s rate. Question stem, rephrased: What is A''s rate? Statement 1: Since B takes 5 hours to produce 50 widgets, B''s ...”
December 4, 2018
Brent@GMATPrepNow posted a reply to Charlie takes 2.5 hours to fly from Los Angeles to Mexico Ci in the Problem Solving forum
“Average speed = (total distance traveled)/(total travel time) So, Average speed = 1200/2.5 = 2400/5 = 4800/10 = 480 mph Answer: D Cheers, Brent”
December 4, 2018
Brent@GMATPrepNow posted a reply to In her position as a real estate agent, Sarah receives a bon in the Problem Solving forum
“Last week, Sarah earned a $4,000 bonus, which decreased her average bonus amount to $4800. This represents a decrease of 4%. Let x = OLD average bonus amount We can write: x - 0.04x = $4800 Simplify: 0.96x = $4800 Solve: x = $4800/(0.96) = $5000 How many sales has Sarah made? Let n = the ...”
December 4, 2018
GMATGuruNY posted a reply to How many positive two-digit integers have a remainder of 1 w in the Problem Solving forum
“A quick lesson on remainders: Onto the problem at hand: a remainder of 1 when divided by 2 x = 2a + 1 = 1, 3, 5, 7... In other words, x must be ODD. a remainder of 4 when divided by 5 x = 5b + 4 = 4, 9, 14, 19... Since x must be odd, we get: x = 9, 19, 29.... a remainder of ...”
December 4, 2018
Brent@GMATPrepNow posted a reply to If there are 4 pairs of twins, and a committee will be in the Problem Solving forum
“Here''s another approach. Take the task of selecting the 3 committee members and break it into stages. Stage 1: Select the 3 twins from which we will select 1 spouse each. There are 4 sets of twins, and we must select 3 of them. Since the order in which we select the 3 twins does not ...”
December 3, 2018
GMATGuruNY posted a reply to If there are 4 pairs of twins, and a committee will be in the Problem Solving forum
“Number of options for the 1st person = 8. Number of options for the 2nd person = 6. (Of the 7 people left, we can''t use the twin of the 1st person chosen, leaving 7-1= 6 choices.) Number of options for the 3rd person = 4. (Of the 6 people left, we can''t use the twins of the 2 people already ...”
December 3, 2018
ceilidh.erickson posted a reply to Most of Western music since the Renaissance has been based in the Critical Reasoning forum
“For more on using this strategy for BOLDFACE questions on CR, see: https://www.beatthegmat.com/gmat-official-guide-2019-in-countries-where-automobile-t303686.html#818265 https://www.beatthegmat.com/gmat-official-guide-2019-boreal-owls-range-over-a-much-t303663.html#818059 ...”
December 2, 2018
ceilidh.erickson posted a reply to Most of Western music since the Renaissance has been based in the Critical Reasoning forum
“The goal in any BOLDFACE question is to deconstruct the argument, and determine the role of each statement: - author''s conclusion / position - support for the author - the counterpoint / what others believe - support for the counterpoint - neutral / background information / establishing ...”
December 2, 2018
ceilidh.erickson posted a reply to 3 Month Study Plan? in the GMAT Strategy forum
“You have more than enough material to study! Here''s what you need to do: Here''s what you should do: 1. Take an adaptive Practice Exam (CAT). If you bought the Mprep books, you''ll have access to our entire suite of practice exams. Don''t prep first - just dive in and take the test, ...”
December 2, 2018