GMATGuruNY posted a reply to Ten theater students are to begin work on a set for a in the Problem Solving forum
“(50 days)/(60 days) = 5/6. To finish the job in 5/6 of the normal time, the crew requires 6/5 of the normal number of students -- an increase of 1/5: (1/5)(10) = 2 more students. The correct answer is A.”
15 minutes ago
GMATGuruNY posted a reply to In how many ways a cricket team consisting of 5 batsmen, 4 in the Problem Solving forum
“From 7 batsmen, the number of ways to choose 5 = 7C5 = (7*6*5*4*3)/(5*4*3*2*1) = 21. From 6 bowlers, the number of ways to choose 4 = 6C4 = (6*5*4*3)/(4*3*2*1) = 15. From 3 wicketkeepers, the number of ways to choose 1 = 3. From 3 allrounders, the number of ways to choose 1 = 3. To combine these ...”
Today
GMATGuruNY posted a reply to How many different arrangements are possible to place seven in the Problem Solving forum
“Let the 3 math books = A, B, C and the remaining 4 books = D, E, F, G. Since the 3 math books must be next to one another, put them together in a block: E.”
Today
GMATGuruNY posted a reply to If 1/x-1/y=1/z, what is the value of y, in terms of x and z? in the Problem Solving forum
“Let x=1 and y=3/2, with the result that 1/z = 1 - 2/3 = 1/3, so z=3. Since the question stem asks for the value of y, the correct answer must yield 3/2 when x=1 and z=3. Since B and D include x-z and thus will yield a negative result, eliminate B and D. Since E includes only multiplication and ...”
Today
GMATGuruNY posted a reply to Is p^3 < p? in the Data Sufficiency forum
“Statements combined: Case 1: p=0, with the result that p is an integer less than 1 In this case, p³=p, so the answer to the question stem is NO. Case 2: p=-2, with the result that p is an integer less than 1 In this case, p³ < p, so the answer to the question stem is YES. Since the answer ...”
Today
GMATGuruNY posted a reply to In the figure shown, AB = AC = 12. Which of the following is in the Problem Solving forum
“https://i.postimg.cc/06HLPxqC/circle-in-a-sector.png AOP passes through the center of the inscribed circle and thus must BISECT sector ACB. AB, AP and AC are all radii of sector ACB and thus are equal. The prompt indicates AB=AC=12. Thus: AP=12. As shown in the figure, AOM is a 30-60-90 ...”
Today
GMATGuruNY posted a reply to The sum of two integers is 27. The larger integer is 25% in the Problem Solving forum
“25% greater = 1/4 greater. If the smaller integer = 4, then the larger integer = 4 + (1/4)4 = 5. The values in red imply that the two integers summing to 27 must be in a RATIO OF 4 TO 5: 4, 5 8, 10 12, 15 The case in blue sums to 27, with the result that larger-smaller = 15-12 = 3. The ...”
Yesterday
GMATGuruNY posted a reply to In the figure above, the angle marked at c has been created in the Data Sufficiency forum
“Since b and c form a straight line, b+c = 180. Thus, the calculate a+b+c, we need to know the value of a. Question stem, rephrased: What is the value of a? Statement 1: SUFFICIENT. Statement 2: No information about a. INSUFFICIENT. The correct answer is A.”
Yesterday
GMATGuruNY posted a reply to At a certain committee meeting only associate professors and in the Problem Solving forum
“Total number of items brought to the meeting = 21. (10 charts and 11 pencils) Number of items brought by each person = 3. (Either 2 pencils and 1 chart or 1 pencil and 2 charts) Thus: Number of people = (total number of items)/(number of items per person) = 21/3 = 7. The correct answer is B.”
Yesterday
GMATGuruNY posted a reply to Four cards are chosen from a standard deck: two aces (one of in the Problem Solving forum
“The following cases are possible: (-1)(1) = -1 (-1)(-2) = 2 (-1)(2) = -2 (1)(-2) = -2 (1)(2) = 2 (-2)(2) = -4 Of the 6 cases above, the 4 in blue each yield a product that is negative, odd or both: 4/6 = 2/3 ≈ 67%. The correct answer is D.”
February 20, 2019
GMATGuruNY posted a reply to A box contains 1 red ball, 3 green balls, 5 yellow balls, 7 in the Problem Solving forum
“Determine the WORST-CASE-SCENARIO -- for each color of ball, the MAXIMUM number that can be removed WITHOUT removing 7 of the same color: 1 red 3 green 5 yellow 6 blue 6 white 6 black Sum = 1+3+5+6+6+6 = 27. Implication: It is possible to remove 27 balls without selecting 7 of the same ...”
February 19, 2019
GMATGuruNY posted a reply to If M, N are integers greater than 1 such that 2M<N, which in the Problem Solving forum
“54, 52 and 50 are options for TWICE the sum. Thus, I, II, and III imply the following options for the ACTUAL SUM: I: 27 II: 26 III: 25 Case 1: M=2 Since it is required that N>2M, N≥5 M=2 and N=5 --> sum = 2+3+4+5 = 14 M=2 and N=6 --> sum increases by 6 --> 14+6 = 20 M=2 and ...”
February 19, 2019
GMATGuruNY posted a reply to If A and B are two fixed constants such that the system in the Problem Solving forum
“The system will have an infinite number of solutions for (x, y) if the two equations are THE SAME: 2(x+y) - A = 0 --> 2x + 2y - A = 0 --> 6x + 6y - 3A = 0 3x + By - 6 = 0 -----------------------> 6x +2By - 12 = 0 The equations in blue will be the same if 3A=12 and 2B=6, with the result ...”
February 18, 2019
GMATGuruNY posted a reply to Is m > n? in the Data Sufficiency forum
“Both statements are satisfied if n=1 and m=2 or if n=1 and m=-2. Since m > n in the first case but m < n in the second case, the two statements combined are INSUFFICIENT. The correct answer is E.”
February 18, 2019
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, ...”
February 17, 2019
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, ...”
February 17, 2019
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 ...”
February 17, 2019
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.”
February 17, 2019
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 ...”
February 16, 2019
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.”
February 16, 2019
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 ...”
February 16, 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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
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
ceilidh.erickson posted a reply to Help me Beat the GMAT in the I just Beat The GMAT! forum
“You can''t find what went wrong? You just told us what went wrong - you over-studied! Being well-rested is absolutely critical for brain functioning (see the studies that say that being sleep-deprived made people perform worse on driving tests than being drunk). There''s nothing that you could ...”
December 2, 2018
ceilidh.erickson posted a reply to A certain bookstore, each notepad costs x dollars and each in the Data Sufficiency forum
“Translate the given information: $10 is enough to buy 5 notepads and 3 markers --> $$5x+3y\le10$$ Translate the question: is $10 enough to buy 4 notepads and 4 markers instead? --> $$4x+4y\le10\ ?$$ Simplify: $$2x+2y\le5\ ?$$ 1) Each notepad cost less than $1. If x < 1, ...”
December 2, 2018
ceilidh.erickson posted a reply to Several friends in a dinner group decide to contribute in the Data Sufficiency forum
“For similar variations on this type of word problem, see: https://www.beatthegmat.com/impossible-question-ps-203-t281881.html#739205 https://www.beatthegmat.com/dollars-t273184.html#707179 ...”
December 2, 2018
ceilidh.erickson posted a reply to Several friends in a dinner group decide to contribute in the Data Sufficiency forum
“Here, we have a version of a rate problem: ($ contribution per person)(# of people) = total $ amount contributed From the question stem, we''re given that the total amount contributed is $36. Let: c = $ contribution per person n = number of people (c)(n) = 36 Since the question is asking ...”
December 1, 2018
ceilidh.erickson posted a reply to the minimum number of straight lines required to in the GMAT Math forum
“This is not a GMAT-style question. The GMAT does not ask for this style of time-consuming puzzle problem. Please still to questions only from GMAC or reputable test prep companies.”
December 1, 2018
GMATGuruNY posted a reply to For each of her sales, a saleswoman receives a commission in the Problem Solving forum
“The first $500 of the $800 sale earns 20% commission, while the remaining $300 earns 30%. Average commission percentage per $800 = (500*20 + 300*30)/800 = (5*20 + 3*30)/8 = 190/8 = 23.75 ≈ 24. The correct answer is B.”
December 1, 2018
GMATGuruNY posted a reply to When a certain tree was first planted, it was 4 feet tall in the Problem Solving forum
“Let x = the yearly increase. Height after 4 years = 4 + 4x. Height after 6 years = 4 + 6x. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. The phrase in red implies the following: The height in the 6th year was 6/5 of the height in the 4th ...”
December 1, 2018
GMATGuruNY posted a reply to If k is a positive integer and n=(k-1)k(k+1), is n a multipl in the Data Sufficiency forum
“Every other even integer is a MULTIPLE OF 4: 2, 4, 6, 8, 10, 12... Thus, the product of two consecutive even integers = product of a multiple of 4 and an even non-multiple of 4 = MULTIPLE OF 8: 2*4 = 8 4*6 = 2*2*2*3 = 8*3 10*12 = 2*5*2*2*3 = 8*15 Statement 1: Since k is odd, k-1 and k+1 ...”
November 30, 2018
GMATGuruNY posted a reply to If x^2=x+1, then x^4=? in the Problem Solving forum
“Squaring both sides, we get: (x²)² + (x+1)² x⁴ = x² + 2x + 1 Substituting x²=x+1 into x⁴ = x² + 2x + 1, we get: x⁴ = (x+1) + 2x + 1 x⁴ = 3x + 2 The correct answer is A.”
November 30, 2018
GMATGuruNY posted a reply to Is the positive integer p a multiple of 50? in the Data Sufficiency forum
“Any integer that is a multiple 10 is also a multiple of 5. Implication: Any integer that satisfies Statement 1 will also satisfy Statement 2. Both statements are satisfied by the following cases: Case 1: p=10, which is a multiple of 10 (and thus is also a multiple of 5) In this case, p is NOT a ...”
November 30, 2018
GMATGuruNY posted a reply to The point A, B, C, and D are on the number line, not in the Data Sufficiency forum
“The drawings below satisfy both statements: http://s4.postimage.org/1yjxdhskk/ABCD_number_line.jpg Since in the first case BD=1 and in the second case BD=17, the two statements combined are insufficient. The correct answer is E.”
November 30, 2018
GMATGuruNY posted a reply to In a business school case competition, the top three teams in the Problem Solving forum
“Case 1: Team A wins a prize, with the result that Team B must win a prize Number of prizes that could be won by A = 3. Number of remaining prizes that could be won by B = 2. Number of teams that could win the third prize = 4. (Any of the 4 remaining teams.) To combine these options, we ...”
November 30, 2018
GMATGuruNY posted a reply to The juice stall at the circus stocked just 2 brands of in the Problem Solving forum
“Let n=50, implying that 50% of the sold juice packs are A, while the other half are B. In other words, the store sells an EQUAL NUMBER of each type of juice pack. Let the store sell 2 OF EACH TYPE of juice pack. Revenue from two $1 packs of A = 2*1 = 2. Revenue from two $1.5 packs of B = ...”
November 29, 2018
GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum
“Let James'' rate = 3 mph. James started from his home and drove eastwards at a constant speed. Exactly 90 minutes after James stated from his home, his brother Patrick started from the same point and drove in the same direction as James did at a different constant speed. Patrick overtook James ...”
November 29, 2018
GMATGuruNY posted a reply to The equation of a circle in the x-y coordinate plane is x^2 in the Problem Solving forum
“The equation for a circle with its center at the origin and a radius of r is as follows: x² + y² = r². Thus, x² + y² = 25 is a circle with its center at the origin and a radius of 5. A point on this circle will have integer coordinates in three cases: Case 1: The radius is horizontal ...”
November 29, 2018
GMATGuruNY posted a reply to On a partly cloudy day, Derek decides to walk back from work in the Problem Solving forum
“The average speed -- 2.8 miles per hour -- must be BETWEEN the two individual rates (s and s+1). Thus, s = 2 miles per hour and s+1 = 3 miles per hour. We can PLUG IN THE ANSWERS, which represent the fraction traveled at 2 miles per hour. When the correct fraction is plugged in, the average ...”
November 28, 2018
GMATGuruNY posted a reply to Eight consecutive integers are selected from the integers 1 in the Data Sufficiency forum
“When consecutive positive integers are divided by positive integer x, the resulting remainders also are consecutive: If x=4: 16/4 = 4 R0. 17/4 = 4 R1. 18/4 = 4 R2. 19/4 = 4 R3. 20/4 = 5 R0. From here, the cycle of remainders will repeat: 0,1,2,3,0,1,2,3... The smallest remainder is 0. The ...”
November 28, 2018
GMATGuruNY posted a reply to A club has 10 members. One president and two vice-presidents in the Problem Solving forum
“Number of options for president = 10. (Any of the 10 members.) From the remaining 9 members, the number of ways to choose 2 to serve as vice-president = 9C2 = (9*8)/(2*1) = 36. To combine these options, we multiply: 10*36 = 360. The correct answer is E.”
November 28, 2018
GMATGuruNY posted a reply to Twelve identical machines, running continuously at the same in the Problem Solving forum
“One approach is to use the following equation: (machines)(time) / output = (machines)(time) / output In the equation above: Machines and time are INVERSELY PROPORTIONAL. As the number of machines increases, the amount of time required to produce the same output decreases. Machines and ...”
November 24, 2018
GMATGuruNY posted a reply to In a plane, there are two parallel lines. One line has 5 in the Problem Solving forum
“One approach: Good Cases = Total Cases - Bad Cases. Total Cases: From 9 points, the number of ways to choose 3 = 9C3 = (9*8*7)/(3*2*1) = 84. Bad Case 1: Choosing 3 collinear points from the 5-point line, with the result that a triangle cannot be formed From the 5 points on this line, the ...”
November 24, 2018
GMATGuruNY posted a reply to Find x^4 + 1/x^4 if x – 1/x = 2. in the Problem Solving forum
“(x – 1/x)² = 2² x² + 1/x² - 2(x)(1/x) = 4 x² + 1/x² - 2 = 4 x² + 1/x² = 6 (x² + 1/x²)² = 6² x⁴ + 1/x⁴ + (2)(x²)(1/x²) = 36 x⁴ + 1/x⁴ + 2 = 36 x⁴ + 1/x⁴ = 34. The correct answer is D.”
November 23, 2018
GMATGuruNY posted a reply to If n is an integer greater than 1, what is the value of n? in the Data Sufficiency forum
“Since the prompt indicates that n is an integer greater than 1, the case in red is not possible. The only value that satisfies Statement 2 is n=2, making Statement 2 SUFFICIENT. The correct answer thus is not C but B.”
November 23, 2018
GMATGuruNY posted a reply to What is the sum of the prime factors of 2^8-1? in the Problem Solving forum
“Alternate approach: 2⁸ - 1 = 256 - 1 = 255 = 5*51 = 5*3*17. Sum of the prime factors = 5+3+17 = 25. The correct answer is E.”
November 22, 2018
GMATGuruNY posted a reply to June 25, 1982, fell on a Friday. On which day of the week in the Problem Solving forum
“Between 1982 and 1987 are 4 non-leap years and 1 leap year. Each non-leap year is composed of 365 days; a leap year is composed of 366 days. Thus, from June 25, 1982 to June 25, 1987, the total number of days = 4(365) + 366. Since June 25, 1982 is a Friday, every passing of 7 days will yield ...”
November 22, 2018
GMATGuruNY posted a reply to A man walking at a constant rate of 4 miles per hour is pass in the Problem Solving forum
“(man''s rate)/(woman''s rate) = (4 mph)/(20 mph) = 1/5. Between the moment when the woman passes the man and the moment when she stops to wait, the woman and the man each travel for 5 minutes. During these 5 minutes, the woman travels x miles. Since the man''s rate is 1/5 the woman''s rate, the ...”
November 21, 2018
GMATGuruNY posted a reply to Six countries in a certain region sent a total of 75 in the Data Sufficiency forum
“Let the 6 countries be A, B, C, D, E and F. The question stem asks whether A≥10. Plug in A=10 (which satisfies statement 2 and is at least 10) and A=9 (which also satisfies statement 2 but is NOT at least 10). To save time, let F=41, which satisfies statement 1. Case 1: Total = 75, ...”
November 21, 2018
GMATGuruNY posted a reply to If n is an integer greater than 1, what is the value of n? in the Data Sufficiency forum
“Statement 1: Here, n can be any prime number. INSUFFICIENT. Statement 2: (n+2)/n = n/n + 2/n = 1 + 2/n. Given that n must be an integer, 1 + 2/n will yield an integer value only if n is a FACTOR OF 2. Factors of 2: 1 and 2. Since n must be greater than 1, n=2. SUFFICIENT. The correct ...”
November 21, 2018
GMATGuruNY posted a reply to A number when divided by 4 and 5 leaves remainders 1 and 4 in the Problem Solving forum
“Please fix the prompt, which has been transcribed incorrectly. It should include the word in red:”
November 20, 2018
GMATGuruNY posted a reply to A woman has seven cookies - four chocolate chip and three in the Problem Solving forum
“Alternate approach: Case 1: Deborah and Kim each receive an oatmeal cookie In this case, 4 chocolate chip cookies and 1 oatmeal cookie remain. The remaining oatmeal cookie has 5 options: Nicole, Ronit, Mark, Terrance, or no one. Total ways = 5. Case 2: Deborah and Kim each receive a ...”
November 20, 2018
GMATGuruNY posted a reply to The Lewiston Road Race is how many kilometers long? in the Data Sufficiency forum
“Statement 1: Rate and time have a RECIPROCAL relationship. A rate ratio of (40kph) : (50kph) = 4:5 implies a time ratio of 5:4 = 10:8. The time ratio in blue implies that -- for the time at 40kph to be 2 hours more than the time at 50kph -- the time at 40kph must be 10 hours, while the time at ...”
November 17, 2018
GMATGuruNY posted a reply to Tim and Glenn are running laps around a circular track. in the Data Sufficiency forum
“Statement 1: The TIME RATIO for Tim and Glenn = 48:60 = 4:5. Since time and rate have a RECIPROCAL relationship, the RATE RATIO for Tim and Glenn = 5:4. Implication: For every 5 laps that Tim runs, Glenn runs only 4 laps. Thus, after running 5 laps, Tim will have run 1 more lap than Glenn. ...”
November 16, 2018
GMATGuruNY posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom in the Problem Solving forum
“Let the one-bedroom rent = $2 per month, implying that the two-bedroom rent = 2 + (50% of 2) = 2 + 1 = $3 per month. Since the rent for a one-bedroom apartment = $2 per month, the total amount to rent a one-bedroom apartment for 12 months = 2*12 = $24. For $24, the number of months yielded for a ...”
November 16, 2018
GMATGuruNY posted a reply to A certain store will order 25 crates of apples. The apples in the Problem Solving forum
“Let W = Winesap crates, M = McIntosh crates, and R = Roma crates. Since a total of 25 crates are ordered, we get: W + M + R = 25. To MINIMIZE the value of W, we must MAXIMIZE the values of M and R. Since the store is to order more crates of Winesap than crates of McIntosh and more crates of ...”
November 15, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“The prompt states: Every day, the two machines operate constantly from 08:00 to 18:00. As shown in my post above, Statement 2 yields the following rate ratio: (W alone) : (W and D together) = 1:5. The rate ratio indicates that -- of every 5 kg produced when W and D work together from 8:00 to ...”
November 15, 2018
GMATGuruNY posted a reply to Organized in 1966 by the Fish and Wildlife in the Sentence Correction forum
“Generally, for + VERBing is an ADJECTIVE serving to modify a NOUN. A: The Breeding Bird Survey uses annual roadside counts along established routes for monitoring. Here, for monitoring seems to be an ADJECTIVE modifying routes, implying that the ROUTES were designed FOR MONITORING. Not the ...”
November 15, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“Statement 1: Let N = 50 kg. Since W and D produce the entire 50 kg over the 10 hours between 8:00 and 18:00, the combined rate for W and D = 50/10 = 5 kg per hour. Since W takes 25 hours to produce N/2 = 25 kg, W''s rate alone = w/t = 25/25 = 1 kg per hour. Of every 5 kg produced each hour ...”
November 14, 2018
GMATGuruNY posted a reply to If x and y are unknown positive integers, is the mean of the in the Data Sufficiency forum
“Known values, in ascending order: 1, 5, 6, 7 Statement 1: x+y = 7 Mean = sum/quantity = (1+5+6+7+x+y)/6 = (1+5+6+7+7)/6 = 26/6 = 13/3 = 4.33. Text EXTREMES. Case 1: x and y are far from each other If x=1 and y=6, we get: 1, 1. 5, 6, 6, 7 Median = (5+6)/2 = 11/2 = 5.5 Case 2: x and y ...”
November 14, 2018
GMATGuruNY posted a reply to How many positive two-digit numbers yield a remainder of 1 in the Problem Solving forum
“Let x = the two-digit number. Since dividing by 4 leaves a remainder of 1, x is equal to one more than a multiple of 4: x = 4k + 1 Since dividing by 14 leaves a remainder of 1, x is equal to one more than a multiple of 14: x = 14m + 1 Since the two expressions in blue must be equal, we ...”
November 14, 2018
ceilidh.erickson posted a reply to What is the area of the quadrilateral with vertices A, B, C, in the Data Sufficiency forum
“Fabio beat me to the post while I was still drawing diagrams <i class="em em-wink"></i> But mine will take you through both statements individually, in case anyone couldn''t rule them out as insufficient.”
November 13, 2018
ceilidh.erickson posted a reply to What is the area of the quadrilateral with vertices A, B, C, in the Data Sufficiency forum
“On a DS geometry question with no diagram given, try to draw different versions of a diagram based on the information given. Question: What is the area of the quadrilateral with vertices A, B, C, and D? We have no information about the quadrilateral to begin with. We will at least need some ...”
November 13, 2018
ceilidh.erickson posted a reply to Of patients over 65 years old who survived coronary bypass in the Critical Reasoning forum
“Whenever we''re asked to WEAKEN an argument, we must find the LOGICAL FLAW that exists between the premises and the conclusion. Premise: Of patients over 65 years old who survived coronary bypass surgery... only 75 percent benefited from the surgery Conclusion: Thus it appears that for one ...”
November 13, 2018
ceilidh.erickson posted a reply to Which of the following most logically completes the passage? in the Critical Reasoning forum
“This question is a variant of one from the Official Guide that asked about boldface portions: https://www.beatthegmat.com/scientists-go-their-work-mostly-before-the-age-of-40-t149219.html#538772”
November 13, 2018
ceilidh.erickson posted a reply to Which of the following most logically completes the passage? in the Critical Reasoning forum
“We want to support the explanation that being in a field for too long diminishes creativity, NOT that being too old in general diminishes creativity. We need a piece of information that connects to length of time in the field. (A) the average age of recipients of scientific research grants is ...”
November 13, 2018
ceilidh.erickson posted a reply to For each country listed in the left column of the table, the in the Problem Solving forum
“Let''s say that A = 1 unit of country A''s currency, X = 1 unit of country X''s currency, and so on. Using the table given, we can create equations: A = 2.2X B = 0.5X C = 0.1X D = 4.0X E = 1.7X Now, plug these into the answer choices: A. 4 units of Country A currency --> 4(2.2X) = ...”
November 13, 2018
ceilidh.erickson posted a reply to Invisible Constraint. OG # 8 vs OG#123 in the Data Sufficiency forum
“Your question is a very understandable one. If you want to be absolutely sure whether there is only one pair of values that work or multiple pairs of values, you should create a table / chart. Start by charting the maximum amount of the variable with the higher coefficient, and see if there''s a ...”
November 13, 2018
ceilidh.erickson posted a reply to If a certain company purchased computers at $2000 each and in the Data Sufficiency forum
“We have 2 unknowns in this question. Let: C = number of computers P = number of printers We''re given information about the cost of each device, but no information about the total cost, or the total number of devices. To solve for C, we''ll need either 2 equations for the 2 variables, or ...”
November 13, 2018
GMATGuruNY posted a reply to On a wedding catering service, An experienced chef can in the Problem Solving forum
“Let service = 24 units. Rate for each experienced chef = w/t = 24/8 = 3 units per hour. Rate for each novice chef = w/t = 24/12 = 2 units per hour. Combined rate for 1 experienced chef and 1 novice chef working together = 3+2 = 5 units per hour. To produce 24 units in 1.6 hours, rate = w/t = ...”
November 13, 2018
GMATGuruNY posted a reply to Jake and Ryan worked together on a job for which they were in the Problem Solving forum
“Let the hourly wage = $1 per hour. Let Ryan''s time = 10 hours, implying that Jake''s time = 10 + (20% of 10) = 10 + 2 = 12 hours. Thus: Total number of work hours = 10+12 = 22 hours. Total pay = (hourly wage)(total number of work hours) = 1*22 = $22. Since the total pay = 10+12 = $22, and ...”
November 13, 2018
GMATGuruNY posted a reply to A store purchased 20 coats that each cost an equal amount in the Data Sufficiency forum
“Statement 1: If the selling price per coat had been twice as much , the store’s gross profit on the 20 coats would have been $2,400 When the selling price per coat is doubled, the resulting profit per coat = (total profit)/(number of coats) = 2400/20 = 120. Case 1: Double the selling price = ...”
November 13, 2018
GMATGuruNY posted a reply to If 60! is written out as an integer, with how many in the Problem Solving forum
“60! = 60*59*58*....*3*2*1. Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of 60! will yield a 0 at the end of the integer representation of 60!. The prime-factorization of 60! is composed of FAR MORE 2''S than 5''s. Thus, the number of 0''s depends on the ...”
November 13, 2018
GMATGuruNY posted a reply to In the figure AB and CD are two diameters of circle. in the Problem Solving forum
“An INSCRIBED ANGLE is formed by two chords. A CENTRAL ANGLE is formed by two radii. When an inscribed angle and a central angle intercept the same two points on a circle, the inscribed angle is 1/2 the central angle. https://i.postimg.cc/qgbxWKdW/Angle-CEB-1.png Here, inscribed angle CFB and ...”
November 12, 2018
GMATGuruNY posted a reply to If x and y are positive integers such that x = 8y + 12, what in the Data Sufficiency forum
“Statement 1: x=12u, where u is an integer and x=8y+12. In other words, x is a multiple of 12. For x to be a multiple of 12, 8y must be a multiple of 12. If y=3, then x = 8*3 + 12 = 36. The GCD of 3 and 36 is 3. If y=6, then x = 8*6 + 12 = 60. The GCD of 6 and 60 is 6. Since the ...”
November 11, 2018
GMATGuruNY posted a reply to Eight women and two men are available to serve on a in the Problem Solving forum
“P(at least 1 man) = 1 - P(no men). P(no men): P(1st person selected is a woman) = 8/10. (Of the 10 people, 8 are women.) P(2nd person selected is a woman) = 7/9. (Of the 9 remaining people, 7 are women.) P(3rd person selected is a woman) = 6/8. (Of the 8 remaining people, 6 are women.) To ...”
November 11, 2018
GMATGuruNY posted a reply to A gardener is going to plant 2 red rosebushes and 2 white in the Problem Solving forum
“Moving LEFT TO RIGHT along the row: P(1st rosebush is white) = 2/4. (Of the 4 rosebushes, 2 are white.) P(2nd rosebush is red) = 2/3. (Of the 3 remaining rosebushes, 2 are red.) P(3rd rosebush is red) = 1/2. (Of the 2 remaining rosebushes, 1 is red.) P(4th rosebush is white) = 1/1. (The one ...”
November 10, 2018
GMATGuruNY posted a reply to Every day at noon, a bus leaves for Townville and travels at in the Problem Solving forum
“Time and rate have a RECIPROCAL RELATIONSHIP: 2 times as fast implies 1/2 the time. 3 times as fast implies 1/3 the time. Let t = the normal time. Since the bus travels today at 7/6 its normal rate, the time today is equal to 6/7 of the normal time: (6/7)t. Since the bus leaves 1/2 hour late ...”
November 9, 2018
ceilidh.erickson posted a reply to GMAT OG 2019 One proposal for preserving rain in the Reading Comprehension forum
“With EXCEPT questions, we must find proof in the passage to eliminate 4 of the 5 answer choices. A. adopt new agricultural technologies line 2: "promote the adoption of new agricultural technologies" B. grow improved plant varieties line 3: "such as improved plant ...”
November 7, 2018
ceilidh.erickson posted a reply to GMAT OG 2019 One proposal for preserving rain in the Reading Comprehension forum
“Here is what we''re told about land tenure: In other words, it''s a fact that kinship ties are more important indicator of land-tenure security than are legal property ties. Indicators aren''t necessarily always causal, but the researchers are clearly assuming that they are. And if this is ...”
November 7, 2018
ceilidh.erickson posted a reply to 12 year out of college, GMAT study plans? in the GMAT Strategy forum
“I''m sorry to hear that it didn''t go as well as you''d hoped. I want to address a few things you said: 1. Inconsistency. Your scores on both quant & verbal have bounced around a lot. Inconsistency in score usually indicates inconsistency in your process: you don''t really have a clear ...”
November 7, 2018
ceilidh.erickson posted a reply to Although they are crucially important, a person's total in the Sentence Correction forum
“This question is testing PRONOUNS, If a sentence begins with an opening modifier or dependent clause containing a pronoun (e.g. "Although they are..."), that pronoun must be referring to the SUBJECT of the main clause that comes after. So in the case of "Although they are..." ...”
November 7, 2018
ceilidh.erickson posted a reply to In California today, Hispanics under the age of eighteen in the Sentence Correction forum
“This question is primarily testing LOGICAL MEANING. Whenever language about percentages or proportions appears on SC or CR, we want to ask ourselves: "what is this the percent *of*? Is it logical and unambiguous?" (A) In California today, Hispanics under the age of eighteen account for ...”
November 7, 2018
GMATGuruNY posted a reply to There are 27 different three-digit integers that can be in the Problem Solving forum
“Given any set that is symmetrical about the median: Sum = (quantity)(median) The set of 3-digit integers that can be formed from the digits 1,2 and 3 is symmetrical about the median (222): ...212, 213, 221, 222, 223, 231, 232... Thus: Sum of the 27 integers = (quantity)(median) = 27*222 = ...”
November 7, 2018
GMATGuruNY posted a reply to Is x^2>xy? in the Data Sufficiency forum
“For the purposes of a Y/N DS problem, the rephrase is the equivalent of the original question stem. Original question stem: Is x² > xy? The answer will be YES if y/x is less than 1.. The answer will be NO if y/x is NOT less than 1. Thus, the original question stem can be rephrased as ...”
November 5, 2018
GMATGuruNY posted a reply to Is x^2>xy? in the Data Sufficiency forum
“x² > xy is true only if x is NONZERO, in which case we can safely divide by x², since the square of a nonzero value must be positive: x²/x² > (xy)/x² 1 > y/x Question stem, rephrased: Is y/x < 1? Statement 1: x > y If x=2 and y=1, then y/x =1/2. so the answer to the ...”
November 5, 2018
GMATGuruNY posted a reply to | 1 - | 2 - | 3 - | 4 – π | | | | in the Problem Solving forum
“Let π=3 in the original expression and simplify the blue portion below: | 1 - | 2 - | 3 - | 4 – 3 | | | | Simplify the red portion below; | 1 - | 2 - | 3 - 1 | | | Simplify the green portion below: | 1 - | 2 - 2 | | = | 1 - 0 | = 1 The correct answer choice must yield a value of ...”
November 5, 2018
GMATGuruNY posted a reply to Working alone, three persons P, Q, and R can do a certain in the Problem Solving forum
“Let the job = the LCM of the 3 times = 60 widgets. Maximum time: The maximum time is yielded when the slowest person -- R -- works alone. Since R takes 15 hours to complete the 60-widget job, the maximum time = 15 hours. Minimum time: The minimum time is yielded when all 3 people work ...”
November 4, 2018
GMATGuruNY posted a reply to Triplets Adam, Bruce, and Charlie enter a triathlon. If ther in the Problem Solving forum
“One approach: P(good outcome) = 1 - P(bad outcome). Bad outcome #1: Exactly 1 triplet wins. P(triplet wins 1st place) = 3/9. (Of the 9 competitors, 3 are triplets) P(non-triplet wins 2nd place) = 6/8. (Of the 8 remaining competitors, 6 are non-triplets) P(non-triplet wins 3rd place) = 5/7. ...”
November 4, 2018
ceilidh.erickson posted a reply to GMAT Retake?? in the I just Beat The GMAT! forum
“Here is a post that sums up my advice about whether to retake the exam: https://www.beatthegmat.com/my-advice-to-a-student-w-a-740-wondering-whether-to-retake-t301310.html#810959 You''re only 1 point away from perfect on the quant. To get a 720+, you would have to improve your verbal score. If ...”
November 2, 2018
ceilidh.erickson posted a reply to The difference in average annual income in (OG18) help in the GMAT Verbal & Essays forum
“This type of logical flaw is very common on GMAT CR. I like to call it "Mixed Metrics" - conflating one mathematical concept (difference in incomes increased) with another (actual incomes increased). Any time you see one statistic / metric / mathematical concept swapped in for another, ask ...”
November 2, 2018
ceilidh.erickson posted a reply to The difference in average annual income in (OG18) help in the GMAT Verbal & Essays forum
“If we want to WEAKEN an argument, we must first find the logical flaws - the missing information - between the premises and the conclusion. Premises: The difference in average annual income in favor of employees who have college degrees, compared with those who do not have such degrees, doubled ...”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“Nicely done! Because the comparison in D allows for more than one logical interpretation, eliminate D. In fact, the ambiguity cited above is the most compelling reason to eliminate D.”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“X led to Y implies that X did not directly cause Y but that X was a factor that helped to yield Y. SC755 in the OG17: An inability to adapt led to their extinction. Here, an inability to adapt did not directly cause the extinction but was a factor that helped to yield the extinction. A cause ...”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“Generally, COMMA + as-clause implies that the clause after as LEADS to the preceding clause, with the result that the two clauses happen concurrently. An OA in GMATPrep: The steel industry has changed radically over the last two decades, as large, integrated companies such as Bethlehem Steel have ...”
November 2, 2018
GMATGuruNY posted a reply to Barry walks from one end to the other of a 30-meter long in the Problem Solving forum
“Let B = Barry''s rate and W = the walkway''s rate. The distance can be ANY VALUE. Let the distance = 240 meters. WITH the walkway, the time = 30 seconds: Here, Barry and the walkway WORK TOGETHER, so we ADD their rates: B+W = d/t = 240/30 = 8 meters per second. AGAINST the walkway, the ...”
November 2, 2018
ceilidh.erickson posted a reply to What is the area of the trapezoid shown? in the Data Sufficiency forum
“Poster, can you clarify where you found this? I don''t recognize this problem, and I can''t find it in any of our materials. I think it''s unlikely that this is actually a Manhattan Prep question.”
November 1, 2018
ceilidh.erickson posted a reply to A market research company surveyed users of the toothpaste in the Data Sufficiency forum
“We''re given that everyone in the survey used at least one of Brand X and Brand Y. We can think of this as: (Brand X users) + (Brand Y users) - (people who used both) = Total or, since we''re asked for a percentage: X + Y - B = 100 If we want to know the percentage who used Brand Y, we''ll ...”
November 1, 2018
ceilidh.erickson posted a reply to Lyme disease is caused by a bacterium transmitted to humans in the Critical Reasoning forum
“Whenever you''re asked to STRENGTHEN or WEAKEN an argument, it''s implied that there is a logical flaw - a missing piece - in the argument. Break down the argument carefully and identify what''s missing before diving into the answer choices. Premises: - deer ticks pick up Lyme bacterium while ...”
November 1, 2018
GMATGuruNY posted a reply to At a family summer party, each of the x members of the in the Problem Solving forum
“Let the x family members = the product of the two denominators = 3*7 = 21. Number who chose to have a hamburger = (1/3)(21) = 7. Since 1/7 of the hamburger-eaters also had a hot dog, the number who had both = (1/7)(7) = 1. Thus, the number who did NOT have both = (total members) - (number who had ...”
November 1, 2018
GMATGuruNY posted a reply to How many positive five-digit integers contain the digit in the Problem Solving forum
“I believe that the prompt above is outdated; regardless, it does not list a correct answer. The prompt below appears in Manhattan''s 5 lb. Book of GRE Practice Problems: Case 1: 57XXX Number of options for the hundreds digit = 10. (Any digit 0-9.) Number of options for the tens digit = 10. ...”
November 1, 2018
GMATGuruNY posted a reply to Two teachers, Ms. Ames and Mr. Betancourt, each had N in the Data Sufficiency forum
“Since the N cookies can be divided evenly among 24 or 18 students, N must be divisible by both 24 and 18. One way to determine the LCM of two integers is to take multiples of the LARGER integer until we get a multiple of the SMALLER integer. Multiples of 24: 24, 48, 72... We can stop here: the ...”
November 1, 2018
GMATGuruNY posted a reply to Did one of the 3 members of a certain team sell at least 2 in the Data Sufficiency forum
“Statement 1: If NONE of the members sells at least 2 tickets, then the 3 members sell a maximum of 1 ticket each, yielding the following total: 1+1+1 = 3. Too small, since the total number of tickets sold = 6. Implication: For a total of 6 tickets to be sold, one of the 3 members must sell at ...”
October 31, 2018
GMATGuruNY posted a reply to A football team averaged 35 points per game over the first in the Problem Solving forum
“This is a weighted average/mixture problem. Average score for the first N games = 35. Score for the final game = 28. Average score for the MIXTURE of all the games = 34. Step-by-step instruction for the alligation approach: Step 1: Plot the 3 averages on a number line, with the average ...”
October 31, 2018
ceilidh.erickson posted a reply to In countries where automobile insurance includes in the Critical Reasoning forum
“By the way, it''s interesting to note that the GMAT will sometimes use the same argument but ask different questions about it. Here is the same argument from the OG, but with different portions bolded: ...”
October 31, 2018
ceilidh.erickson posted a reply to In countries where automobile insurance includes 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 This ...”
October 31, 2018
GMATGuruNY posted a reply to 3, 6, 9, 12, … are multiples of 3. How many multiples of 3 in the Problem Solving forum
“The difference between the endpoints of the range = 200-10 = 190. Since neither endpoint is a multiple of 3, we can count the multiples of 3 simply by dividing 3 into 190: 190/3 ≈ 63. The correct answer is D.”
October 31, 2018
GMATGuruNY posted a reply to A group of 20 friends formed an investment club, with each in the Problem Solving forum
“Let d=100. After the value of the stock increases by 40% to $140, the share received by each of the 20 friends = 140/20 = 7. The correct answer must yield a value of 7 when d=100. Only E works: (7d)/100 = (7*100)/100 = 7. The correct answer is E.”
October 30, 2018
GMATGuruNY posted a reply to The average weight of a class is x pounds. When a new in the Problem Solving forum
“We can PLUG IN THE ANSWERS and use alligation. To learn about alligation, check my posts here: https://www.beatthegmat.com/statistics-average-question-t288903.html https://www.beatthegmat.com/alligation-method-t293459.html https://www.beatthegmat.com/mean-t266852.html Let O = the original ...”
October 30, 2018
GMATGuruNY posted a reply to Machines X and Y can work at their respective constant rates in the Data Sufficiency forum
“Statement 1: Time and rate have a RECIPROCAL relationship. Since X and Y together take 2/3 as long as Y alone, X and Y together work 3/2 as fast as Y alone. Thus, if Y''s rate alone = 2 units per hour, then X and Y''s combined rate = (3/2)(2) = 3 units per hour, implying that X''s rate alone = ...”
October 30, 2018
GMATGuruNY posted a reply to Set S contains nine distinct points in the coordinate plane. in the Problem Solving forum
“To form a triangle, we must select 3 points such that at most 2 are collinear. Case 1: Select 3 points not on the x-axis From the 4 points not on the x-axis, the number of ways to choose 3 = 4C3 = (4*3*2)/(3*2*1) = 4. Case 2: Select 1 point on the x-axis and two points not on the x-axis From ...”
October 29, 2018
GMATGuruNY posted a reply to Employees at a company will vote for an executive team of in the Problem Solving forum
“Number of options for president = 8. (Any of the 8 candidates.) Number of options for treasurer = 7. (Any of the 7 remaining candidates.) From the 6 remaining people, the number of ways to choose 3 to serve as warrant officers = 6C3 = (6*5*4)/(3*2*1) = 20. To combine these options, we multiply: ...”
October 29, 2018
GMATGuruNY posted a reply to A set of pencils can be evenly shared between 2, 3, 4, 5 and in the Problem Solving forum
“For the set of pencils to be shared evenly, the total number of pencils must be divisible by the total number of children. Thus, the correct answer must be divisible by 2, 3, 4, 5 and 6. Of the five answer choices, only E is divisible by 2, 3, 4, 5 and 6. The correct answer is E.”
October 29, 2018
GMATGuruNY posted a reply to (x^2-3x+2)(y^2-5y+6)=? in the Data Sufficiency forum
“Statement 1: Substituting x=1 into (x² - 3x + 2)(y² - 5x + 6), we get: (1 - 3*1 + 2)(y² - 5x + 6) = (0)(y² - 5x + 6) = 0. SUFFICIENT. Statement 2: Substituting y=1 into (x² - 3x + 2)(y² - 5x + 6), we get: (x² - 3x + 2)(1² - 5*1 + 6) = (x² - 3x + 2)(2). Since the value of x is ...”
October 29, 2018
GMATGuruNY posted a reply to How many integers are there between, but not including, in the Data Sufficiency forum
“Statement 1: Case 1: r=0 and s=10 Integers between r and s: 1, 2, 3, 4, 5, 6, 7, 8, 9 --> 9 integers Case 2: r=1 and s=11 Integers between r and s: 2, 3, 4, 5, 6, 7, 8, 9, 10 --> 9 integers Case 3: r=2 and s=12 Integers between r and s: 3, 4, 5, 6, 7, 8, 9, 10, 11 --> 9 ...”
October 28, 2018
GMATGuruNY posted a reply to Both Betty and Wilma earn annual salaries of more than $5000 in the Data Sufficiency forum
“Statement 1: Betty''s annual salary is closer to $50000 than Wilma''s is. On a number line: -----50,000---B---W Thus, W > B. SUFFICIENT. Statement 2: Betty''s annual salary is closer to $35000 than it is to Wilma''s annual salary. Case 1: -----35,000-----50,000---B---W Case 2: ...”
October 28, 2018
GMATGuruNY posted a reply to In a right triangle, the longer leg is two more than three in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the length of the shorter leg. When the correct answer is plugged in, the area = 400. B: 20 Longer leg = two more than three times the shorter leg = 2 + 3*20 = 62. Area = (1/2)(20)(62) = 620. Since the area is too great, a smaller answer choice is ...”
October 27, 2018
GMATGuruNY posted a reply to A framed picture is shown above. The frame, shown shaded, is in the Data Sufficiency forum
“Statement 1: Test one case that also satisfies Statement 2. Case 1: The frame is 8 inches tall, with the result that the total area of the frame and picture combined = 6*8 = 48 Area of the picture = (total area) - (shaded region) = 48-24 = 24. Implication: The width of the frame is 1 inch, ...”
October 27, 2018
GMATGuruNY posted a reply to What is the largest prime factor of the expression 3^8 − 2 in the Problem Solving forum
“A general rule: Given x^(even power) - y^(even power), where x and y are distinct positive integers, we can always simplify by applying the difference of two squares. Each time we apply the difference of two squares to the expression in blue, the exponents are reduced by 1/2. For example: x⁸ - ...”
October 26, 2018
GMATGuruNY posted a reply to Jazz and blues recordings accounted for 6 percent of the in the Data Sufficiency forum
“Let J = jazz and blues revenue in 1998. Statement 1: Case 1: Total revenue in 1998 = 100 In this case, J = 5% of 100 = 5. Case 2: Total revenue in 1998 = 1000 In this case, J = 5% of 1000 = 50. Since J can be different values, INSUFFICIENT. Statement 2: In other words: (jazz and blues ...”
October 26, 2018
GMATGuruNY posted a reply to x and y are non-negative integers. If xy+2x+3y=0, then y=? in the Problem Solving forum
“NONNEGATIVE implies that we should test ZERO. Let x=0. Substituting x=0 into xy + 2x + 3y = 0, we get: 0*y + 2*0 + 3y = 0 3y = 0 y = 0 The correct answer is A.”
October 26, 2018
GMATGuruNY posted a reply to Set S contains consecutive natural numbers from 1 to 100, in in the Problem Solving forum
“For any evenly spaced set: sum = (count)(median) Sum of the first n even numbers = n * median of the first n even numbers Sum of the last n odd numbers = n * median of the last n odd numbers Since the ratio of the two sums = 16/85, we get: (n * median of the first n even numbers) / (n * ...”
October 26, 2018
GMATGuruNY posted a reply to Quentin's income is 60% less than Rex's income, and Sam's in the Problem Solving forum
“Let Rex''s income = 100. Since Quentin''s income is 60% less than Rex''s, Quentin''s income = 100 - (60% of 100) = 100-60 = 40. Since Sam''s income is 25% less than Quentin''s, Sam''s income = 40 - (25% of 40) = 40-10 = 30. After Rex gives 60% of his income to Sam, Sam''s new income = 30 + (60% ...”
October 25, 2018
GMATGuruNY posted a reply to If |x-6|=2x, then x=? in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of x. Since an absolute value cannot be equal to a negative value, the correct answer cannot be A or B. D: x=2 If we plug x=2 into |x-6|=2x, we get: |2-6| = 2*2 |-4| = 4 4 = 4. Success! The correct answer is D.”
October 25, 2018
GMATGuruNY posted a reply to Tom drives from town A to town B, driving at a constant 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 mph, ...”
October 25, 2018
GMATGuruNY posted a reply to gmat prep 2 in the Critical Reasoning forum
“The negation test is not recommended for Evaluate CRs. It can be applied to Assumption CRs and Inference CRs.”
October 24, 2018
GMATGuruNY posted a reply to Computer-based activities in the Critical Reasoning forum
“The answer choices are already phrased as statements. The OA is a statement that weakens the conclusion. OA: Computer owners in the United States predominately belong to a demographic group that have long been known to spend less time watching television. This statement indicates that a lack of ...”
October 24, 2018
GMATGuruNY posted a reply to Noelle walks from point A to point B at an average speed of in the Problem Solving forum
“Let the distance between A and B = the LCM of the two speeds = 5*6 = 30 kilometers, implying that the distance for the entire round trip = 60 kilometers. At a rate of 5 kph, the time to travel the 30 kilometers from A to B = d/r = 30/5 = 6 hours. At a rate of 6 kph, the time to travel the entire ...”
October 24, 2018
GMATGuruNY posted a reply to What is the median number of employees assigned per project in the Data Sufficiency forum
“In ascending order of EMPLOYEES PER PROJECT, let the projects be numbered 1 through 100: 1, 2, 3.....49, 50, 51, ....98, 99, 100. Projects 50 and 51 determine the MEDIAN number of employees: Question rephrased: How many employees are assigned to PROJECTS 50 and 51? Looking at the two ...”
October 24, 2018
GMATGuruNY posted a reply to Three photographers , Lisa, Mike and Norm, take photos of a 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 by ...”
October 24, 2018
GMATGuruNY posted a reply to Circle ABCD in the diagram above is defined by the equation in the Problem Solving forum
“Circle ABCD: The equation for a circle with a center at the origin and a radius of r is x² + y² = r². The equation for circle ABCD is x² + y² = 5². Thus, circle ABCD has a radius of 5. Line EF: 3y = 4x + 25 y = (4/3)x + 25/3 Slope = 4/3. A radius drawn to a point of tangency forms ...”
October 24, 2018
ceilidh.erickson posted a reply to At a constant speed of 72 kilometers per hour, a vehicle in the Problem Solving forum
“"Units Control" has a great space-age ring to it, like something you''d shout from the bridge on Star Trek! I like it.”
October 23, 2018
ceilidh.erickson posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum
“Fabio, I definitely agree with your sentiment generally! But Mitch & I have worked side by side for years, with much mutual respect (I''m assuming!). I''ve never known him to knowingly step on anyone''s toes. I''m sure we''ve all had the experience of someone else posting while we were in the ...”
October 23, 2018
GMATGuruNY posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum
“In many cases, similar or identical solutions are posted when two experts respond at virtually the same time, with the result that the second poster is not aware of the first. The time stamps for the two solutions here indicate that both solutions were posted at 11:45am.”
October 23, 2018
ceilidh.erickson posted a reply to Although the earliest surviving Greek inscriptions written in the Critical Reasoning forum
“For more on CR Boldface questions, see: https://www.beatthegmat.com/gmat-official-guide-2019-boreal-owls-range-over-a-much-t303663.html#818059 https://www.beatthegmat.com/gmat-official-guide-2019-in-countries-where-automobile-t303686.html#818265 ...”
October 23, 2018
ceilidh.erickson posted a reply to Although the earliest surviving Greek inscriptions written in the Critical Reasoning forum
“With BOLDFACE questions in CR, break down the argument according to the following roles: - author''s conclusion - supporting premises - counterpoint / someone else''s conclusion - support for the counterpoint - general phenomena / neutral facts We can break down this argument as follows: ...”
October 23, 2018
ceilidh.erickson posted a reply to While political discourse and the media in the United States in the Critical Reasoning forum
“If we want to EVALUATE an argument, we must first figure out where the argument is flawed: we must find a missing link between premises & conclusion. Conclusion: The drop in enrollment of foreign-born graduate students since 2001 will hurt America’s competitiveness in basic research and ...”
October 23, 2018
ceilidh.erickson posted a reply to If x and y are positive integers, what is the remainder when in the Data Sufficiency forum
“It''s important to note here that certain digits will always maintain the same units digit, regardless of the exponent: 0, 1, 5, and 6. All other digits [2, 3, 4, 7, 8, and 9] will change units digits, depending on the exponent. More on establishing those patterns here: ...”
October 23, 2018
ceilidh.erickson posted a reply to If Machine B and Machine C work together at their constant in the Data Sufficiency forum
“Machines working together will work at the SUM of their individual rates. Since the question is asking us for the proportion of the work that Machine B completed, we would need to know the proportion that A & C together completed. (1) Machine A and Machine B, working together at their ...”
October 23, 2018
ceilidh.erickson posted a reply to At a constant speed of 72 kilometers per hour, a vehicle in the Problem Solving forum
“For more on doing unit conversions correctly, see: https://www.manhattanprep.com/gmat/blog/2016/01/20/heres-how-to-do-gmat-unit-conversions-like-a-pro/ https://www.manhattanprep.com/gmat/blog/2013/01/14/remember-your-units/”
October 23, 2018
ceilidh.erickson posted a reply to At a constant speed of 72 kilometers per hour, a vehicle in the Problem Solving forum
“Here''s an easy way to set up UNIT CONVERSIONS - set it up as fractions, so that numerators and denominators of the same unit cancel: https://i.postimg.cc/JD8nxJtz/Screenshot-2018-10-23-12-18-55.png https://i.postimg.cc/cKR1vHTy/Screenshot-2018-10-23-12-20-01.png Now there''s no confusion ...”
October 23, 2018
GMATGuruNY posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum
“Rates can be ADDED TOGETHER. 7 Machine As and 11 Machine Bs can produce 250 widgets per hour. 7A + 11B = 250 8 Machine As and 22 Machine Cs can produce 600 widgets per hour. 8A + 22C = 600 4A + 11C = 300 Adding together 7A + 11B = 250 and 4A + 11C = 300, we get: 11A + 11B + 11C = 550 A ...”
October 23, 2018
ceilidh.erickson posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum
“At first, it might seem as if we don''t have enough information to solve. We have 3 unknowns (the rates of Machines A, B, and C), but only 2 equations. Since this is Problem Solving and not Data Sufficiency, though, (and there is no "cannot be determined" answer) there must be some way to ...”
October 23, 2018
GMATGuruNY posted a reply to 25 integers are written on a board. Are there at least two in the Data Sufficiency forum
“The wording in Statement 1 does not convey a clear meaning: For every value in the list, if the value is increased by 1, the number of distinct values in the list does not change. Here, the term in red could convey to some test-takers that EVERY VALUE in the list is to be increased by 1. Not the ...”
October 23, 2018
GMATGuruNY posted a reply to The annual rent collected by a corporation from a certain in the Data Sufficiency forum
“Let the 1997 rent = 100. Increase in 1998 = (x/100)(100) = x. Thus, rent in 1998 = 100+x. Decrease in 1999 = (y/100)(100+x) = y + xy/100 For the rent to be greater in 1999 than in 1997, the increase in 1998 (x) must be greater than the decrease in 1999 (y + xy/100). Question stem, ...”
October 21, 2018
GMATGuruNY posted a reply to During a 3 year period, the profits of company X changed by in the Data Sufficiency forum
“Statement 1: If profits increase by $X from the first year to the second year, then they must increase by $0 from the second year to the third year, with the result that the increase in profits from the first year to the third year (X+0 = $X) is the same as the increase in profits from the first ...”
October 21, 2018
GMATGuruNY posted a reply to OG The estimated number of homeschooled students in the Problem Solving forum
“Percent greater or percent increase: (bigger value - smaller value)/(smaller value) * 100 Percent less or percent decrease: (bigger value - smaller value)/(bigger value) * 100”
October 21, 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: 25Q + 10D = 170 5Q + 2D = 34 To minimize the number of coins, we must maximize the value of Q. If Q=6, then D=2, with the result that 5Q + 2D = (5*6) + (2*2) = 34. In this case, the total number of coins = 6+2 = 8. If the value of Q decreases, then the total number of coins will ...”
October 20, 2018
GMATGuruNY posted a reply to doubt 3 in the Sentence Correction forum
“having + VERBed is a viable construction. An introductory HAVING + VERBed modifier implies PRIOR ACTION: an action completed before the main verb. HAVING FINISHED his dessert, John LEFT the table. Here, HAVING FINISHED implies PRIOR ACTION -- an action completed before John LEFT the table. ...”
October 20, 2018
GMATGuruNY posted a reply to All attendees at a university gathering are faculty or in the Data Sufficiency forum
“Neither statement offers any information about the number of attendees who are alumni. Thus, the two statements combined are INSUFFICIENT. The correct answer is E.”
October 20, 2018
GMATGuruNY posted a reply to If n is an integer, which of the following must be divisible in the Problem Solving forum
“Test n=0. A --> n³ - 4n = 0³ - (4*0) = 0 B --> n³ + 4n = 0³ + (4*0) = 0 C --> n² + 1 = 0² + 1 = 1 D --> n² - 1 = 0² - 1 = -1 E --> n² - 4 = 0² - 4 = -4 Only the options in green yield a multiple of 3. Eliminate C, D and E. Test n=1 in the remaining answer ...”
October 20, 2018
GMATGuruNY posted a reply to At a certain industrial manufacturer, an open tank contains in the Problem Solving forum
“Since 6% of the 1000-gallon tank is fluorine, the amount of fluorine = (6/100)(1000) = 60 gallons. Since the total volume decreases at a rate of 10 gallons per day for 25 days, the decrease in the total volume = 10*25 = 250 gallons. Remaining total volume = 1000-250 = 750 gallons. Since 60 of the ...”
October 20, 2018
GMATGuruNY posted a reply to Is 1+x+x^2+x^3+x^4+x^5+x^6 < 1/(1-x)? in the Data Sufficiency forum
“CRITICAL POINTS in an equality occur when the two sides are EQUAL or the inequality is undefined. Here, the two statements provide the critical points for the inequality in the prompt: When x=0, the two sides are equal. When x=1, the inequality is undefined. To determine the range(s) where the ...”
October 20, 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 ...”
October 19, 2018
GMATGuruNY posted a reply to If a rectangle’s length is a+b and its area is (1/a)+(1/b) in the Problem Solving forum
“Let a=b=0.5, implying that the rectangle''s length = a+b = 0.5+0.5 = 1 and that its area = (1/0.5) + (1/0.5) = (10/5) + (10/5) = 2+2 = 4. Since the rectangle has an area of 4 and a length of 1, its width = 4. The correct answer must yield a value of 4 when a=b=0.5. Only E works: 1/ab = 1/(0.5 * ...”
October 19, 2018
GMATGuruNY posted a reply to When positive integer N is divided by positive integer J, in the Problem Solving forum
“N/J = 134.08 = 13408/100 = 3352/25. The resulting ratio indicates that N must be multiple of 3352 and that J must be a multiple of 25. Of the five answer choices, only E is a multiple of 25. The correct answer is E.”
October 19, 2018
GMATGuruNY posted a reply to A container contains 4 red marbles and 8 blue marbles. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of blue marbles in the second container. When the correct answer is plugged in, the probability of selecting 2 red marbles OR 2 blue marbles = 1/2. B: 4 blue marbles, implying a total of 10 marbles in the second container Case1: 2 red ...”
October 19, 2018
GMATGuruNY posted a reply to Two printing presses begin printing currency at the same in the Problem Solving forum
“Since F produces 1000 5-dollar bills each minute, the dollar amount produced by F each minute = 1000*5 = $5000. Since T produces 200 20-dollar bills each minute, the dollar amount produced by T each minute = 200*20 = $4000. Thus, every minute F surpasses T by $1000. Since F surpasses T by $1000 ...”
October 18, 2018
GMATGuruNY posted a reply to Brian purchased a bouquet of 40 flowers for his mother for in the Problem Solving forum
“= We can PLUG IN THE ANSWERS, which represent the number of tulips. When the correct answer is plugged in, the total cost = $48. D: 24 tulips, implying 16 roses, for a total of 40 flowers Since each of the 24 tulips costs $1, and each of the 16 roses costs $1.50, we get: Total cost = (24*1) ...”
October 18, 2018
ceilidh.erickson posted a reply to The heignt of an equilateral triangle is the side of a in the Problem Solving forum
“Very well said! And thank you ;)”
October 16, 2018
ceilidh.erickson posted a reply to The heignt of an equilateral triangle is the side of a in the Problem Solving forum
“Well thanks, you made my day, too! We''re all here to learn from each other & share what we know, right? I''ve always found it weird and transparent when people try to "talk over" each other in forums like this. Much better to act like collaborators!”
October 16, 2018
ceilidh.erickson posted a reply to The heignt of an equilateral triangle is the side of a in the Problem Solving forum
“Yes, good point! I didn''t include it in my diagram, but we can''t just assume it''s 90 - we have to justify it with the reasoning Fabio outlined.”
October 16, 2018
ceilidh.erickson posted a reply to If x, y, and z are all nonzero numbers, and x = y + z, which in the Problem Solving forum
“We can also rearrange the equation algebraically. If x = y + z, then: y = x - z z = x - y Compare these to our answer choices: (A) (y - z)/x We know that y + z = x, so (y + z)/x = 1. If all terms are non-zero, then there''s no way that y + z = y - z, so (y - z)/x must not equal 1. (B) ...”
October 16, 2018
ceilidh.erickson posted a reply to The heignt of an equilateral triangle is the side of a in the Problem Solving forum
“Here''s an easier way to look at it: we''ve created another 30-60-90 triangle between A, B, and the midpoint of the base of the larger triangle. If the base = 1, then half the base = 1/2. This is the hypotenuse of the right triangle. Thus, AB must be half that length: 1/4. ...”
October 16, 2018
ceilidh.erickson posted a reply to What is the remainder if 7^10 is divided by 100? in the Problem Solving forum
“A general note: the GMAT will often use "remainder when divided by 10" as code for "units digit," or "remainder when divided by 100" as "the last 2 digits." Here are more examples along those lines: ...”
October 16, 2018
ceilidh.erickson posted a reply to Among the Tsonga, a Bantu-speaking group of tribes in in the Sentence Correction forum
“This question is primarily testing IDIOMS and meaning. Among the Tsonga, a Bantu-speaking group of tribes in southeastern Africa, dance teams represent their own chief at the court of each other, providing entertainment in return for food, drink, and lodging. (A) the court of each other, ...”
October 16, 2018
ceilidh.erickson posted a reply to The pioneering research of Lewis Latimer and Thomas Edison, in the Sentence Correction forum
“A. of Lewis Latimer and Thomas Edison, who became known for his invention of the light bulb, - when "who" follows "Lewis Latimer and Thomas Edison", it should modify both of them. Since it continues "his invention," we must rearrange the sentence so that we''re only ...”
October 16, 2018
ceilidh.erickson posted a reply to A popular beach has long had a dolphin feeding program in in the Critical Reasoning forum
“Here is the general process you should use for EXPLAIN DISCREPANCY problems: 1. Evaluate the given circumstance / phenomenon. 2. Think about what you would have expected / what the normal outcome would likely have been (this is usually unstated). 3. Think about why that''s at odds with the ...”
October 16, 2018
ceilidh.erickson posted a reply to Beat the GMAT! 760 in just over 4 weeks in the I just Beat The GMAT! forum
“I would strongly urge everyone on this forum NOT to follow this poster''s sleep regimen. This poster may think that reducing sleep contributed to his success, but it likely did more harm than good. The GMAT is not a test you can cram for. Very broadly speaking, cramming stores a lot of ...”
October 16, 2018
GMATGuruNY posted a reply to A certain NYC taxi driver has decided to start charging a in the Problem Solving forum
“Let r=100 cents. For 3 people, the cost per mile = 3*100 = 300 cents = 3 dollars. Let x = 2 miles. Regular cost for 3 people to travel 2 miles = 3*2 = 6 dollars. With a 50% discount, the cost in dollars = 3. This is the target. Plug x=2 and r=100 into the answers to see which yields the ...”
October 16, 2018
GMATGuruNY posted a reply to (1-1/10)(1-1/11)(1-1/12)…(1-1/100) =? in the Problem Solving forum
“(1-1/10)(1-1/11)(1-1/12)…(1-1/99)(1-1/100) = (9/10)(10/11)(11/12)....(98/99)(99/100). The values in blue all cancel out, leaving only the values in red: 9/100. The correct answer is C.”
October 16, 2018
GMATGuruNY posted a reply to A rectangular garden is to be twice as long as it is wide. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the length. When the correct answer is plugged in, perimeter = 360. B: 140 Since the length is twice the width, W = 70, with the result that the perimeter = 140+140+70+70 = 420. Since the perimeter is too great, a SMALLER answer choice is needed. ...”
October 16, 2018
GMATGuruNY posted a reply to Is the sum of 7 different positive integers greater than or in the Data Sufficiency forum
“Statement 1: Least possible case: 1+2+3+9+10+11+12 = 48. Since the least possible case is greater than or equal to 48, the answer to the question stem is YES. SUFFICIENT. Statement 2: Least possible case: 1+2+3+4+5+6+12 = 33. Greatest possible case: 6+7+8+9+10+11+12 = 63. Since the answer ...”
October 16, 2018
GMATGuruNY posted a reply to If x, y, and z are all nonzero numbers, and x = y + z, which in the Problem Solving forum
“x = y + z is valid if x=2, y=1 and z=1. The correct answer must yield a value of 1 when x=2, y=1 and z=1. Only E works: (x-z)/y = (2-1)/1 = 1. The correct answer is E.”
October 16, 2018
GMATGuruNY posted a reply to If |x+1|=2|x-1|, x=? in the Data Sufficiency forum
“Case 1: Signs unchanged x+1 = 2(x-1) x+1 = 2x-2 3 = x Case 2: Signs changed on ONE SIDE -x-1 = 2(x-1) -x-1 = 2x-2 1 = 3x 1/3 = x Resulting solutions: x=3 or x=1/3 Statement 1: Since x < 1, only x=1/3 is a viable solution. SUFFICIENT. Statement 2: Since x>0, both x=1/3 ...”
October 15, 2018
GMATGuruNY posted a reply to Lindsay can paint 1/x of a certain room in one hour. If in the Problem Solving forum
“Let the room = 20 units. Let x = 4. Since Lindsay paints 1/x of the room in 1 hour, Lindsay''s rate = (1/4) * 20 = 5 units per hour. Since Lindsay and Joseph paint the entire room in 1 hour, their combined rate = 20 units per hour. Thus, Joseph''s rate = (combined rate) - (Lindsay''s rate) ...”
October 15, 2018
GMATGuruNY posted a reply to The principal feature of the redesigned checks is a series o in the Sentence Correction forum
“Generally, a COMMA + VERBing modifier serves to modify the nearest preceding action and the agent of this action. C: instructions that...will help merchants confirm a check''s authenticity, by including reminders to watch the endorsement. .Here, COMMA + by including seems to modify merchants ...”
October 15, 2018
GMATGuruNY posted a reply to What is the remainder if 7^10 is divided by 100? in the Problem Solving forum
“When a positive integer is divided by 100, the remainder is yielded by the last two digits: 123/100 = 1 R23 548/100 = 5 R48 692/100 = 6 R92 Thus: The remainder when 7¹⁰ is divided by 100 is equal to the last two digits of 7¹⁰. Calculate the last two digits for consecutive powers of 7 ...”
October 14, 2018
GMATGuruNY posted a reply to Alice, Barbara, and Cynia work on identical tasks at differe in the Data Sufficiency forum
“TIME and RATE have a reciprocal relationship. Statement 1: The time ratio for Barbara and Alice = (14 hours)/(21 hours). The rate ratio for Barbara and Alice is equal to the reciprocal of the time ratio: (B''s rate)/(A''s rate) = 21/14 = 3/2. Let B = 3 units per hour and A = 2 units per ...”
October 13, 2018
GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum
“Let James'' rate = 3 mph. James started from his home and drove eastwards at a constant speed. Exactly 90 minutes after James stated from his home, his brother Patrick started from the same point and drove in the same direction as James did at a different constant speed. Patrick overtook James ...”
October 13, 2018
GMATGuruNY posted a reply to A certain club has 10 members, including Harry. One of the 1 in the Problem Solving forum
“Each of the 10 members has an EQUAL chance of being elected secretary. P(Harry is elected secretary) = 1/10. Each of the 10 members has an EQUAL chance of being elected treasurer. P(Harry is elected treasurer) = 1/10. Since EITHER outcome is favorable, we ADD the fractions: 1/10 + 1/10 = 2/10 = ...”
October 13, 2018
GMATGuruNY posted a reply to Challenge question: What is the sum of all in the Problem Solving forum
“x^(2/3) - x^(1/3) - 2 = 4 x^(2/3) - x^(1/3) - 6 = 0 D.”
October 12, 2018
October 12, 2018
GMATGuruNY posted a reply to Hard Assumption - Manhattan in the Critical Reasoning forum
“The conclusion is constrained to the case at hand: Of the 10 babies recently placed with parents, 8 were given to friends of the staff. The assumption is that the premise (the parents given babies -- including the 8 friends --all far surpassed the agency''s criteria) is sufficient to prove the ...”
October 11, 2018
ceilidh.erickson posted a reply to Strategy to score 700+ in the GMAT Verbal & Essays forum
“I''m not really sure what you''re asking here. You say that you don''t have time or energy to prep, but then you''re asking for advice about how get a 700? If there were a magical shortcut to a 700, everyone would take it, and there would be no need for prep programs. The way to get a 700 is to ...”
October 11, 2018
ceilidh.erickson posted a reply to GMAT preparation Group at 42 in the Let's Meet Up forum
“The most important thing is to determine *why* you want an MBA at this age. Why not an EMBA? If you''re seeking to level up your skills, there may be ways to do that outside of a full-time program. It''s generally the case that elite MBA programs want to accept students who are relatively early ...”
October 11, 2018
ceilidh.erickson posted a reply to DS: Difficulty level: 700, Source: GMATPrep in the GMAT Math forum
“The square root of a square is a coded way of saying absolute value. Whether the base is positive or negative, squaring will make it positive, and when given a root sign, we only take the positive root: https://i.postimg.cc/PN1FGTXN/Screenshot-2018-10-11-15-57-39.png So, we can rephrase the ...”
October 11, 2018
GMATGuruNY posted a reply to If every boy in a kindergarten class buys a soda and every in the Problem Solving forum
“Let: b = the number of boys g = the number of girls s = the number of cents for each soda j = the number of cents for each juice box Note: All of the values above must be POSITIVE INTEGERS. Case One: If every boy in a kindergarten class buys a soda and every girl in the same class buys a ...”
October 11, 2018
ceilidh.erickson posted a reply to Full time student in the GMAT Strategy forum
“If you''re finding that the Mprep Foundations guides are easy, then move on to the strategy guides. I''d recommend doing a handful of the drill sets at the end of each chapter in the Foundations guides to test your knowledge / build your basic muscles back up, but you can probably skip reading the ...”
October 11, 2018
GMATGuruNY posted a reply to Julie opened a lemonade stand and sold lemonade in two in the Data Sufficiency forum
“Let X = the number of 52¢ lemonades and Y = the number of 58¢ lemonades. Since the question stem asks for the number of 52¢ lemonades, we get: What is the value of X? Statement 1: X+Y = 9 Since X can be any value between 0 and 9, inclusive, INSUFFICIENT. Statement 2: 52X + 58Y = 492 ...”
October 11, 2018
GMATGuruNY posted a reply to For the students in a Physical Fitness Class Section #1, the in the Data Sufficiency forum
“Range = highest - lowest. Thus: Lowest = highest - range. In Section 1, lowest = highest - range = X-R. In Section 2, lowest = highest - range = Y-S. If the lowest weight in Section 1 is greater than the lowest weight in Section 2, we get: X-R > Y-S X+S > Y+R. Question ...”
October 11, 2018
GMATGuruNY posted a reply to Angela’s grade was in the 90th percentile out of 80 grades in the Problem Solving forum
“Percentile means the percentage below: (total below)/(total grades) * 100. Angela''s 80-student class: Since Angela''s grade was in the 90th percentile, 90% of the grades were below Angela''s: (90/100)(80) = 72. 100-student class: Since 19 grades were higher than Angela''s, the remaining ...”
October 10, 2018
GMATGuruNY posted a reply to There are 5 cars to be displayed in 5 parking spaces with in the Problem Solving forum
“Alternate approach: The 3 red cars must occupy a combination of 3 spaces. From 5 spaces, the number of ways to choose a combination of 3 for the red cars = 5C3 = (5*4*3)/(3*2*1) = 10. Number of options for the blue car = 2. (Either of the 2 remaining spaces.) Number of options for the yellow ...”
October 10, 2018
GMATGuruNY posted a reply to Hard Assumption - Manhattan in the Critical Reasoning forum
“Premise: All of the applicants given babies far surpassed the adoption criteria. Conclusion: In placing 8 of the 10 babies with friends, the staff was not guilty of favoritism. Apply the NEGATION TEST. When the correct answer is negated, the conclusion will be invalidated. B, negated: Of ...”
October 10, 2018
GMATGuruNY posted a reply to A group of medical interns at Bohemus Medical School want to in the Problem Solving forum
“In other words: How many ways can 5 girls and 5 guys be divided into pairs, if each pair must consist of one girl and one guy? Number of options for the first girl = 5. (Any of the 5 guys.) Number of options for the second girl = 4. (Any of the 4 remaining guys). Number of options for the ...”
October 9, 2018
GMATGuruNY posted a reply to If x, y, and z are positive numbers, Is z between x and y? in the Data Sufficiency forum
“Statement 1: x < 2z < y Let x=2 and y=10. In this case: 2 < 2z < 10 1 < z < 5. If z=4, then it is between x=2 and y=10. If z=1.5, then it is not between x=2 and y=10. INSUFFICIENT. Statement 2: 2x < z < 2y Let x=2 and y=10. In this case: 2*2 < z ...”
October 9, 2018
GMATGuruNY posted a reply to If s is an integer between 0 and 10, is t less than the av in the Data Sufficiency forum
“The average of s and 10 lies HALFWAY between s and 10 on the number line: s------------AVERAGE------------10 Statement 1: Since t closer to 10 than to s, t must be greater than the average of s and 10, as shown here: s-----------AVERAGE---t----------10 Thus, the answer to the question stem is ...”
October 9, 2018
GMATGuruNY posted a reply to A group of 10 people consists of 3 married couples and 4 si in the Problem Solving forum
“Good committees = total committees - bad committees. Total committees: From 10 people, the number of ways to choose 4 = 10C4 = (10*9*8*7)/(4*3*2*1) = 210. Bad committees: Since a good committee includes at most 1 married couple, a bad committee is composed of 2 married couples. From 3 ...”
October 9, 2018
GMATGuruNY posted a reply to Problem solving: Difficulty level: 700, Source: Princeton in the Problem Solving forum
“For any evenly spaced set: sum = (number)(median) We can PLUG IN THE ANSWERS, which represent the sum. Since the number of integers can be 5 or 7, the sum must be a multiple of both 5 and 7. Eliminate A, which is not divisible by 5. Eliminate D, which is not divisible by 7. The equation in ...”
October 7, 2018
GMATGuruNY posted a reply to Health insurance Plan A requires the insured to pay $1000 or in the Problem Solving forum
“THE INSURED is the person covered by the insurance. Plan A: If $1000 is LESS than 50% of the cost level, then THE INSURED pays $1000, and PLAN A pays the remainder. If $1000 is MORE than 50% of the cost level, then THE INSURED pays 50% of the cost level, and PLAN A pays the remainder. Plan ...”
October 6, 2018
GMATGuruNY posted a reply to John tossed a fair coin 3 times. What is the probability in the Problem Solving forum
“P(TTH) = 1/2 * 1/2 * 1/2 = 1/8. Since H can occur on the 1st, 2nd or 3rd flip, we multiply by 3: 3*(1/8) = 3/8. The correct answer is C.”
October 6, 2018
GMATGuruNY posted a reply to Mixture Problem DS in the Data Sufficiency forum
“Yes -- each statement conveys the same information, since doubling the total volume is the equivalent of reducing the acid concentration by 1/2.”
October 6, 2018
GMATGuruNY posted a reply to The value of a share was 25% less in the 2nd quarter over in the Problem Solving forum
“Let the 1st-quarter value = 100. Since 2nd-quarter value is 25% less, the 2nd-quarter value = 100 - (25% of 100) = 100 - 25 = 75. Since the 3rd-quarter value is 20% more than the 2nd-quarter value, the 3rd-quarter value = 75 + (20% of 75) = 75 + 15 = 90. Since the 4th-quarter value must equal 120 ...”
October 6, 2018
GMATGuruNY posted a reply to Mixture Problem DS in the Data Sufficiency forum
“Statement 1 indicates that 80 grams of water are added to the 80 grams of original solution, DOUBLING the total volume from 80 grams to 160 grams Statement 2 indicates that the added water reduces the acid concentration by 1/2. Doubling the total volume will reduce the acid concentration by 1/2 ...”
October 6, 2018
GMATGuruNY posted a reply to Each year for 4 years, a farmer increased the number of in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the original number of trees. Since the number of trees increases by 1/4 each year, the correct answer must be a multiple of 4. The last 2 digits of a multiple of 4 must themselves form a multiple of 4. Eliminate A (1250) and C (2250), since 50 is ...”
October 5, 2018
ceilidh.erickson posted a reply to Advocates of a large-scale space-defense research project in the Critical Reasoning forum
“We''re asked for 4 answer choices that WEAKEN the conclusion. (Note: this does NOT mean to look for one answer that strengthens! It''s often the case that we''ll find 4 answers that weaken and one that''s irrelevant.) First, let''s determine where the argument is flawed: Premises: since ...”
October 5, 2018
ceilidh.erickson posted a reply to Guitar strings often go "dead"--become less respon in the Critical Reasoning forum
“When we''re asked what information would help us to EVALUATE an argument, we''re looking for a question for which a "yes" answer would weaken the argument and a "no" answer would strengthen the argument (or vice versa). Premise: Guitar strings often go "dead"--become ...”
October 5, 2018
GMATGuruNY posted a reply to A chessboard is an 8×8 array of identically sized squares. in the Problem Solving forum
“Case 1: Every 6-block rectangle with a base of 2 and a height of 3 yields 4 possible L-shapes: https://i.postimg.cc/1gJCfb5J/chessboard_L_shape_1.png Chessboard: https://i.postimg.cc/LYJThXW8/chessboard_whole.png The base for the 6-block rectangle shown above can appear in rows 1 through 6, ...”
October 5, 2018
GMATGuruNY posted a reply to Amit and Ian paint a wall in alternating shifts. First Amit in the Problem Solving forum
“During each of Amit''s 4 shifts, he paints 1/2 of the room, leaving 1/2 the room unpainted. Since 1/2 of the room is left unpainted FOUR TIMES, the total fraction left unpainted as a result of Amit''s 4 shifts = (1/2)⁴. Since Ian works after each of Amit''s first 3 shifts, Ian paints a total ...”
October 5, 2018
ceilidh.erickson posted a reply to A political candidate collected $1,749 from a fund raising in the Problem Solving forum
“If we want to MAXIMIZE the number of contributors, we must MINIMIZE the contributions of each person. We want as many people as possible to contribute exactly $50, so think of the greatest multiple of $50 that''s less than $1749. 34 people contributing exactly $50 would get us to $1700. Since we ...”
October 4, 2018
GMATGuruNY posted a reply to A thin piece of wire 40 meters long is cut into two pieces. in the Problem Solving forum
“Since the answer choices are in terms of a variable -- the value of r -- we can PLUG IN. Let the ENTIRE WIRE be used to form the square. Then: Perimeter of the square = 40. Side = 10. Area = 100. Circle area + square area = 0 + 100 = 100. This is our target. Since the circle has no ...”
October 4, 2018
GMATGuruNY posted a reply to If x and y are positive integers, is x^2*y^2 even ? in the Data Sufficiency forum
“x²y² will be even unless both x and y are ODD. Question stem, rephrased: Are x and y both odd? Statement 1: x+5 is prime number greater than 2 and thus must be ODD. Implication: x+5 = ODD x = ODD - 5 = ODD - ODD = EVEN. Since x is even, x and y cannot both be odd. SUFFICIENT. ...”
October 4, 2018
GMATGuruNY posted a reply to A hiker walking at a constant rate of 4 miles per hour is in the Problem Solving forum
“Rate and time have a RECIPROCAL RELATIONSHIP. The RATE RATIO for the hiker and cyclist = 4 mph : 20 mph = 1:5. Thus: The TIME RATIO for the hiker and cyclist = the reciprocal of the rate ratio = 5:1. Implication: The hiker will take 5 TIMES AS LONG as the cyclist to travel the same ...”
October 4, 2018
GMATGuruNY posted a reply to How many ounces of water must be added to 10 ounces of 3 % in the Problem Solving forum
“Alcohol percentage in the original solution: 3%. Alcohol percentage in the added water: 0%. Alcohol percentage in the mixture: 1%. Let S = the original solution and W = the added water. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: ...”
October 3, 2018
GMATGuruNY posted a reply to Vivian drives to her sister's house and back. She takes the in the Problem Solving forum
“When the same distance is traveled at two different speeds, the average speed for the entire trip will be a bit LESS than the average of the two speeds. Since (70+50)/2 = 60, the average speed for Vivian''s''s entire trip must be a bit less than 60. The correct answer is B.”
October 3, 2018
GMATGuruNY posted a reply to Tom’s Mom is five times as old as him. In 6 years, Tom’ in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represents Tom''s current age. When the correct answer is plugged in, Mom''s age in 6 years will be 3 times Tom''s age in 6 years. D: Tom = 6 Since Mom is currently 5 times as old as Tom, Mom = 5*6 = 30. Tom''s age in 6 years = 6+6 = 12. ...”
October 3, 2018
GMATGuruNY posted a reply to If 3 different numbers are selected from the first 8 prime n in the Problem Solving forum
“First 8 prime numbers: 2, 3, 5, 7, 11, 13, 17, 19. The sum will be even if 2 is among the three numbers selected, with the result that the sum = EVEN PRIME + ODD PRIME + ODD PRIME = EVEN. Since 3 NUMBERS are selected from 8 OPTIONS, the probability that 2 will be among the three numbers selected = ...”
October 2, 2018
GMATGuruNY posted a reply to In a certain office, 50 percent of the employees are college in the Data Sufficiency forum
“Let T = the total number of employees. Since 60% of the employees are over 40, we get: Over 40 = 0.6T 30% of those over 40 -- in other words, 30% of the expression in blue -- have master''s degrees. Thus: Over 40 with master''s = 0.3(0.6T). To calculate the value of the expression in ...”
October 2, 2018
GMATGuruNY posted a reply to On a 20 mile course, Pat bicycled at an average rate of 30 in the Problem Solving forum
“Since Pat travels at 30 miles per hour for the first 12 minutes -- the equivalent of 1/5 hour -- the distance traveled in the first 12 minutes = (30)(1/5) = 6 miles. Since the remaining 14 miles are traveled at 8 miles per hour, the time to travel the remaining 14 miles = 14/8 = 7/4 hours = 1 hour ...”
October 2, 2018
GMATGuruNY posted a reply to 190 students go to a school bake sale. 95 buy a chocolate in the Problem Solving forum
“Total = Group 1 + Group 2 - Both + Neither Here: Total = 190. Group 1 = 95 who buy chocolate chip. Group 2 = 75 who buy peanut butter. Plugging these values into the equation above, we get: 190 = 95 + 75 - Both + Neither 20 + Both = Neither Neither = 20 + Both. To minimize the value of ...”
October 2, 2018
GMATGuruNY posted a reply to Is x^3-x>0? in the Data Sufficiency forum
“Question stem, rephrased: Is x³ > x? Statement 1: x > 1 When a positive value greater than 1 is cubed, the result is greater than the original number: x=2 --> 2³ > 2 x=3 --> 3³ > 3 x=4 --> 4³ > 4 In every case, x³ > x. Thus, the answer to the rephrased ...”
October 2, 2018
GMATGuruNY posted a reply to The greatest common factor of 16 and the positive integer n in the Problem Solving forum
“The greatest common factor of 16 and the positive integer n is 4, and the greatest common factor of n and 45 is 3. Draw a VENN DIGRAM showing where the prime factors of n, 16 and 45 overlap: https://i.postimg.cc/xkyNCFg7/GCF_Venn_n_16_and_45.jpg The diagram implies the following: Since n and ...”
October 2, 2018
GMATGuruNY posted a reply to Five letters A, P, P, L and E are listed in a row. How many in the Problem Solving forum
“Good arrangements = total arrangements - bad arrangements. Total arrangements: Number of ways to arrange 5 elements = 5!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of identical elements can be ARRANGED. The reason: When the ...”
October 1, 2018
GMATGuruNY posted a reply to If a, b, c, d, e are consecutive positive integers such that in the Problem Solving forum
“For any set of consecutive integers, average = median. Let the five integers = 1, 2, 3, 4, 5. Average of 2, 3, 4 and 5 = 3.5. Average of 1, 2, 3, and 4 = 2.5. Difference between the averages = 3.5 - 2.5 = 1. The correct answer is D.”
September 30, 2018
GMATGuruNY posted a reply to If a, b, c, d, e are integers such that a<b<c<d< in the Data Sufficiency forum
“Statement 1: For any set of consecutive integers, average = median. Case 1: 1, 2, 3, 4, 5 Average of 2, 3, 4 and 5 = 3.5. Average of 1, 2, 3, and 4 = 2.5. Difference between the averages = 3.5 - 2.5 = 1. Case 2: 2, 3, 4, 5, 6 Average of 3, 4, 5, and 6 = 4.5. Average of 2, 3, 4 and 5 = ...”
September 30, 2018
GMATGuruNY posted a reply to If x is the greatest common factor of 36 and 96, what is the in the Problem Solving forum
“36 = 2*2*3*3 96 = 2*2*2*2*2*3 GCF = the product of the factors in blue = 2*2*3 = 12. Sum of the digits = 1+2 = 3. The correct answer is B.”
September 30, 2018
GMATGuruNY posted a reply to Bob invested $2000 in fund A and $1000 in fund B. Over the in the Problem Solving forum
“Fund A after 2 years: 2000 + (10% of 2000) + (2)(1% of 2000) = 2000 + 200 + 2(20) = 2240. Fund B after 1 year: 1000 + (30% of 1000) = 1000 + 300 = 1300. Fund B after 2 years: 1300 + (30% of 1300) = 1300 + 390 = 1690. Difference after two years: 2240 - 1690 = 550. The correct answer is ...”
September 30, 2018
GMATGuruNY posted a reply to If a photocopier makes 2 copies in 1313 second, then, at the in the Problem Solving forum
“Using ratios, convert 4 minutes into copies: (4 minutes) * (60 seconds)/(1 minute) * (2 copies)/(1/3 second) = 1440 copies. The correct answer is E.”
September 30, 2018
GMATGuruNY posted a reply to Lindsay can paint 1/x of a certain room in 20 minutes. What in the Problem Solving forum
“Let the room = 20 units. Let x = 4. Since Lindsay paints 1/x of the room in 20 minutes -- the equivalent of 1/3 hour -- Lindsay''s rate = (1/4) * 20 = 5 units per 1/3 hour = 15 units per hour. Since Lindsay and Joseph paint the entire room in 1 hour, their combined rate = 20 units per hour. ...”
September 29, 2018
GMATGuruNY posted a reply to 50% of students' study science and 30% of science students in the Problem Solving forum
“Let the total number of students = 100. Since 50% of the students study science, the number of science students = (50/100)(100) = 50, implying that the number of non-science students = 100-50 = 50. Since 30% of the 50 science students score more than 80%, the number of science students who ...”
September 29, 2018
GMATGuruNY posted a reply to A garden center sells a certain grass seed in 5-pound bags in the Problem Solving forum
“5-pound bags = ($13.85)/5 ≈ $3 per pound. 10-pound bags = ($20.43)/10 = more than $2 per pound. 25-pound bags = ($32.25)/25 = less than $1.50 per pound. To minimize the cost, we must maximize the number of 25-pound bags, which offer seed at the lowest price per pound. Two 25-pound bags = 50 ...”
September 29, 2018
GMATGuruNY posted a reply to Which of the following equations is NOT equivalent to in the Problem Solving forum
“If we plug y=-3 into 4x² = y²-9, we get: 4x² = (-3)² - 9 4x² = 0 x = 0. Test x=0 and y=-3 in the answer choices. When the question stem includes the phrase which of the following, the correct answer is likely to be D or E. D: 2x = y-3 Plugging in x=0 and y=-3, we get: 2*0 = -3-3 0 = ...”
September 28, 2018
GMATGuruNY posted a reply to If non- negative integers n & p are not both odd, in the Problem Solving forum
“If n=p=0, options A, B, C and D each yield a even value, indicating that these options do NOT have to be odd. Eliminate A, B, C and D. The correct answer is E.”
September 28, 2018
GMATGuruNY posted a reply to Is |x+y|<|x|+|y|? in the Data Sufficiency forum
“Since an absolute value cannot be negative, both sides of the question stem are NONNEGATIVE, enabling us to safely square the inequality: (|x+y|)²< (|x|+|y|)² x² + y² + 2xy < x² + y² + 2|x||y| xy < |xy| The resulting inequality is valid only if x and y have DIFFERENT SIGNS. ...”
September 28, 2018
GMATGuruNY posted a reply to The shaded portion of the rectangular lot shown above in the Problem Solving forum
“ALWAYS KEEP YOUR EYES ON THE ANSWER CHOICES. C, D and E imply that the flower bed is probably a 6-8-10 triangle in which y=6, x = y+2 = 6+2 = 8, and z=10. Check whether this triangle satisfies the condition that the flower bed has an area of 24 square yards: Area of a 6-8-10 triangle = ...”
September 27, 2018
GMATGuruNY posted a reply to Anna wants to distribute chocolates among her four children in the Problem Solving forum
“Let the total number of chocolates = the LCM of the four denominators 2, 5, 6 and 12 = 60. Number of chocolates given to the four children: (1/2)(60) = 30 (1/5)(60) = 12 (1/6)(60) = 10 (1/12)(60) = 5 Total number of chocolates = 30+12+10+5 = 57. The correct answer is C.”
September 27, 2018
GMATGuruNY posted a reply to In 2004, 2,400 condos sold, 15% of the total housing units in the Problem Solving forum
“Of the units sold, non-condos constitute 85% = 85/100 = 17/20. Implication: Of every 20 units sold, 17 are non-condos, with the result that the number of non-condos must be a multiple of 17. A. 16000 B. 13600 C. 12400 D. 11200 E. 8600 Only the portion in green is a multiple of 17: ...”
September 27, 2018
GMATGuruNY posted a reply to If the probability of Ronaldo will score at least 3 goals in in the Problem Solving forum
“Let G = at least 3 goals and NG = not at least 3 goals. Let W = win the match and NW = not win the match. Use a DOUBLE-MATRIX to organize the data: https://i.postimg.cc/JHLj6Tyr/matrix_goals_wins_0.png The probability that Ronaldo will score at least 3 goals in the match is 0.59. The ...”
September 27, 2018
ceilidh.erickson posted a reply to If z is a multiple of 9 and w is a multiple of 4, is zw a in the Data Sufficiency forum
“Btw, this question is nearly identical to this OG question: https://www.beatthegmat.com/is-xy-a-multiple-of-105-t274522.html#712134”
September 27, 2018
ceilidh.erickson posted a reply to If z is a multiple of 9 and w is a multiple of 4, is zw a in the Data Sufficiency forum
“First, REPHRASE the given information: - if z is a multiple of 9, it contains two factors of 3. - if w is a multiple of 4, it contains two factors of 2. - the product zw must contain two factors of 2 and two factors of 3. Now rephrase the question: Is zw a multiple of 126 --> does zw ...”
September 27, 2018
ceilidh.erickson posted a reply to Time for me to Stop Studying on my Own? - GMAT Quant Help in the GMAT Math forum
“You said that you got a 38-V, 38-Q on your 1st CAT. That would track to a 630, not a 500: https://www.manhattanprep.com/gmat/gmat-score-calculator/ I assume that you mean percentiles. IGNORE YOUR PERCENTILES! They are misleading: ...”
September 26, 2018
GMATGuruNY posted a reply to A set of numbers has an average of 50. If the largest elemen in the Problem Solving forum
“Let S = the smallest number of L = the largest number. Since the largest number is 4 more than 3 times the smallest number, we get: L = 3S + 4 L-4 = 3S (L-4)/3 = S. Since the average is 50 -- and the numbers are not all the same -- S must be LESS THAN 50, while L must be greater than 50. ...”
September 26, 2018
GMATGuruNY posted a reply to What is the sum of the solutions of the equation (x-1)^2=|x- in the Problem Solving forum
“If we replace x-1 with a, we get: a² = |a|. The resulting equation is valid only if a -- in other words, the value of x-1 -- is equal to -1, 0, or 1: x-1 = -1 --> x=0 x-1 = 0 ---> x=1 x-1 = 1 ---> x=2 Sum of the solutions = 0+1+2 = 3. The correct answer is E.”
September 26, 2018
GMATGuruNY posted a reply to If H = [(x^3) - 6(x^2) - x + 30] / (x-5)and x ≠ 5, then H in the Problem Solving forum
“Let x=0, with the result that H = 30/-5 = -6. Now plug x=0 in the answers to see which yields a value of -6. Only A works: x² - x - 6 = 0² - 0 - 6 = -6. The correct answer is A.”
September 26, 2018
GMATGuruNY posted a reply to Robin split a total of $24,000 between 2 investments, X and in the Data Sufficiency forum
“Statement 1: Test one case that also satisfies Statement 2. Case 1: X = 5% and Y = 7% For 5% interest and 7% percent interest to yield the same dollar amount, $7 must be invested at 5% interest for every $5 invested at 7% interest: X --> $7(0.05) = $0.35. Y --> $5(0.07) = $0.35. Thus: ...”
September 25, 2018
GMATGuruNY posted a reply to In how many ways four men, two women and one child can sit a in the Problem Solving forum
“Once the child has been placed at the table: Number of ways to arrange the 2 women in the 2 seats adjacent to the child = 2! = 2. Number of ways to arrange the 4 men in the remaining 4 seats = 4! = 24. To combine these options, we multiply: 2*24 = 48. The correct answer is C.”
September 24, 2018
GMATGuruNY posted a reply to W, X, Y and Z each represent a different number. If the sum in the Problem Solving forum
“Sum of all 4 rows = 3 + 6 + 9 + 0 = 18. Sum of all 4 columns = -2 + 7 + n + 5 = n + 10. The values in blue must be EQUAL, since each represents the sum of all 16 values in the table. Thus: n+10 = 18 n=8. The correct answer is C.”
September 24, 2018
GMATGuruNY posted a reply to How many 3 digit numbers can we make such that two of the in the Problem Solving forum
“Number of digit options for the repeated digit = 9. (Any digit but 0.) Number of digit options for the non-repeated digit = 8. (Any digit but 0 and the digit already used.) Number of position options for the non-repeated digit = 3. (The hundreds place, the tens place, or the units place.) To ...”
September 24, 2018
GMATGuruNY posted a reply to Is 10m > 5n - k? in the Data Sufficiency forum
“Statement 1: n=2m Substituting n=2m into 10m > 5n-k, we get: 10m > 5(2m) - k ? 10m > 10m - k ? 0 > -k ? k > 0 ? No way to determine whether k>0. INSUFFICIENT. Statement 2: |k| = -k This equation is valid only if k≤0. No information about m or n. INSUFFICIENT. ...”
September 23, 2018
GMATGuruNY posted a reply to Machine A and Machine B can produce 1 widget in 3 hours work in the Problem Solving forum
“Algebra: Machine A and Machine B can produce 1 widget in 3 hours working together at their respective constant rates. (A+B)(3) = 1 widget. If Machine A''s speed were doubled, the two machines could produce 1 widget in 2 hours working together at their respective rates. (2A+B)(2) = 1 widget. ...”
September 23, 2018
GMATGuruNY posted a reply to Machine A and Machine B can produce 1 widget in 3 hours work in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent A''s time to produce 1 widget. Since A and B working together take 3 hours to produce 1 widget, A working alone must take MORE than 3 hours. Eliminate A, B and C. Let the value of each widget = 30 units. Since A and B together take 3 hours to produce ...”
September 23, 2018
GMATGuruNY posted a reply to In an office that employs 120 people, m% of the employees in the Data Sufficiency forum
“Use a DOUBLE-MATRIX to organize the data. Statements combined: Case 1: m=25% and c=25% Total number of males = (25/100)(120) = 30. Total number of custodial employees = (25/100)(120) = 30. The following matrix is yielded: https://i.postimg.cc/H88Lq5zN/matrix_custodial_1.png In this case, ...”
September 22, 2018
ceilidh.erickson posted a reply to Best Way to Study with GMAT Books Already Purchased? in the GMAT Strategy forum
“No, I''m afraid this is not a good plan. There are several problems: - there is absolutely no way that you can get a 750 by focusing on quant alone. You have to maximize both quant and verbal. See the score calculator here: https://www.manhattanprep.com/gmat/gmat-score-calculator/ - you''re ...”
September 21, 2018
ceilidh.erickson posted a reply to Taking the GMAT in four days. Need advice calming my nerves in the GMAT Strategy forum
“CONGRATULATIONS!!! That''s a fantastic score! I always tell my students to take the exam twice. With all the time and money you''re planning to invest in graduate school, why not invest another day of your time + $250 to maximize your score? There''s always a margin of error of +/- 20 pts or so, ...”
September 21, 2018
ceilidh.erickson posted a reply to If m > 0, y > 0, and x is m percent of 2y, then, in te in the Problem Solving forum
“Here''s another similar problem to try, both algebraically and with plugging numbers: https://www.beatthegmat.com/if-m-0-and-x-is-t68852.html#800983”
September 21, 2018
ceilidh.erickson posted a reply to If m > 0, y > 0, and x is m percent of 2y, then, in te in the Problem Solving forum
“Here''s another way to set it up algebraically: x is m percent of 2y ---> \E.”
September 21, 2018
ceilidh.erickson posted a reply to Because of a rare type of fungus that killed off many cacao in the Critical Reasoning forum
“When we''re asked to EVALUATE an argument, we must first determine how the argument is logically flawed. Premises: - Because of a rare type of fungus that killed off many cacao trees in Brazil, there was an unusually meager harvest of cacao beans this year. - The wholesale price of cocoa ...”
September 21, 2018
ceilidh.erickson posted a reply to With its plan to develop seven and a half acres of shore in the Sentence Correction forum
“Because the dependent clause beginning with "that" is modifying "a large number of communities," the verb should be PLURAL. Remember that in English, certain expressions with prepositions are considered plural: - some of the people are... - all of the ducks have... - many of ...”
September 21, 2018
ceilidh.erickson posted a reply to When there is less rainfall than normal, the water level of in the Critical Reasoning forum
“When you have a CR problem that asks you to EXPLAIN A DISCREPANCY, it''s usually in this format: - It''s generally true that ______. - Normally, you''d think this would mean ______. - In this case, though, _______. We need to find an answer that 1) keeps the original conditions true, ...”
September 21, 2018
ceilidh.erickson posted a reply to The proportion of women among students enrolled in higher in the Critical Reasoning forum
“In order to EVALUATE an argument, we must first find the logical flaw in the argument. This argument is conflating two different metrics: 1. the proportion of women among total students: (women students)/(women students + non-women students) 2. the proportion of all women of a certain age who ...”
September 21, 2018
GMATGuruNY posted a reply to In these difficult economic times, those who have---Veriats in the Sentence Correction forum
“The default referent for a subject pronoun is the subject of the preceding INDEPENDENT CLAUSE. A: Those who have public pensions are being pursued strongly by pension advance companies that operate without much oversight from banking regulators, but they are now drawing scrutiny. Here, the default ...”
September 21, 2018
GMATGuruNY posted a reply to GMATPREP Question - what is the subject in the Sentence Correction forum
“This interpretation is not valid. The comparative in blue is clearly an ADJECTIVE describing a city.. Since as big as refers not to China but to A CITY. no comparison between China and Singapore is implied. The sentence unambiguously compares A CITY to Singapore, as discussed below. ...”
September 21, 2018
GMATGuruNY posted a reply to If m > 0, y > 0, and x is m percent of 2y, then, in te in the Problem Solving forum
“Let y=100, implying that 2y = 200. Let m=100. x is m percent of 2y. Since m=100 and 2y=200, x = 100% of 200 = 200. m is what percent of x? m/x = 100/200 = 1/2 = 50%. This is our target. Now plug y=100 into the answers to see which yields the target value of 50. Only E works: 5000/y = ...”
September 21, 2018
GMATGuruNY posted a reply to If 7 < m < 11 and −2 < n < 5, then which of th in the Problem Solving forum
“To determine the lower limit and the upper limit of mn, calculate mn using every combination of endpoints (7 and 11 for m, -2 and 5 for n): mn = (7)(-2) = -14. mn = (7)(5) = 35. mn = (11)(-2) = -22. mn = (11)(5) = 55. The LOWER limit is the LEAST of the results above: -22. The UPPER ...”
September 21, 2018
GMATGuruNY posted a reply to The square ACEG shown below has an area of 36 units squared. in the Problem Solving forum
“Almost no math is needed here. Answer choice A implies the following: BCD is a 45-45-90 triangle in which each leg has a length of 1. DEF is a 45-45-90 triangle in which each leg has a length of 5. Answer choice E implies the following: BCD is a 45-45-90 triangle in which each leg has a ...”
September 20, 2018
GMATGuruNY posted a reply to If Albert can travel 200 miles in 4 hours, how many hours in the Problem Solving forum
“Since Albert travels 200 miles in 4 hours, his rate = 200/4 = 50 mph. When the correct answer is divided into 350 miles, the resulting rate must be 50 mph. Only C works: 350/7 = 50. The correct answer is C.”
September 20, 2018
GMATGuruNY posted a reply to In four years, Andy will be twice as old as Betsy. How old in the Data Sufficiency forum
“In four years, Andy will be twice as old as Betsy. Since Andy''s age in 4 years is twice Betsy''s age in 4 years, we get: A+4 = 2(B+4) A+4 = 2B+8 A-2B = 4. Statement 1: Since Andy''s age 4 years ago is twice Betsy''s current age, we get: A-4 = 2B A-2B = 4. Same equation as given in the ...”
September 20, 2018
GMATGuruNY posted a reply to How many multiples of 33 lie between 101 and 1,000, inclusiv in the Problem Solving forum
“Since 1000 - 101 ≈ 900 -- and the answer choices are a bit spread out -- we can count the multiples of 33 simply by dividing 33 into 900: 900/33 = 300/11 = a bit more than 27. Thus, there are 27 multiples of 33 between 101 and 1000. The correct answer is B.”
September 20, 2018
GMATGuruNY posted a reply to Comparison - GMAT paper test in the Sentence Correction forum
“OA: A neutron star, as small as 12 miles in diameter but containing half as much matter as the Sun, has a gravitational force at its surface about 67 billion times greater than that on Earth. The green portion conveys the following meaning: The words in brackets are omitted so that the green ...”
September 19, 2018
GMATGuruNY posted a reply to Rasheed bought two kinds of candy bars, chocolate and toffee in the Data Sufficiency forum
“I believe that the problem has been transcribed incorrectly. Statement 1 should indicate that Rasheed bought not 2 fewer packages but only 1 fewer package, as shown in the following screen shot: https://i.postimg.cc/t7bcm77Z/rasheed_Gprep-ds-2.jpg If we know the number of chocolate BARS that ...”
September 19, 2018
GMATGuruNY posted a reply to √3-2|+|3-√2|+|5+√3|+|1-√2|=? in the Problem Solving forum
“|a-b| = the distance between a and b. |a+b| = |a-(-b| = the distance between a and -b. |√3-2| + |3-√2| + |5+√3| + |1-√2| = |5+√3| + |√3-2| + |1-√2| + |3-√2| = |√3+5| + |√3-2| + |1-√2| + |3-√2| = |√3-(-5)| + |√3-2| + |1-√2| + |3-√2| The red terms ...”
September 19, 2018
GMATGuruNY posted a reply to On the number line shown, the distance between 0 and a, a in the Problem Solving forum
“In the number line shown, the distance between 0 and a, a and b, and a and c is in the ratio of 1:2:3. To determine the ratio of a to b to c, TEST AN EASY CASE. Let a=1. Since a is ONE PLACE to the right of 0, b must be TWO PLACES to the right of a (implying that b=3), while c must be THREE ...”
September 18, 2018