# 800guy

beatthegmat started following skyfall2013
Today
Brent@GMATPrepNow posted a reply to W, X, Y and Z each represent a different number. If the sum in the Problem Solving forum
“KEY CONCEPT: The sum of all of the rows = The sum of all of the columns So, 3 + 6 + 9 + 0 = (-2) + 7 + n + 5 Solve: n = 8 Answer: C Cheers, Brent”
Today
Brent@GMATPrepNow posted a reply to If x^y = 1 then what is the in the Data Sufficiency forum
“Target question: What is the value of x? Given: x^y = 1 If x^y = 1, then there are 3 possible cases: case i: x = 1, and y = any value (e.g., 1^9 = 1) case ii: x = -1, and y = an even integer (e.g., (-1)^4 = 1) case iii: x = any non-zero value, and y = 0 (e.g., 7^0 = 1) Statement ...”
Yesterday
Brent@GMATPrepNow posted a reply to If 893 × 78 = p, which of the following is equal to 893 × in the Problem Solving forum
“Given: 893 x 78 = P 893 x 79 = 893 x (78 + 1) = (893)(78) + (893)(1) = P + 893 = D Cheers, Brent”
Yesterday
Brent@GMATPrepNow posted a reply to In an office that employs 120 people, m% of the employees in the Data Sufficiency forum
“I thought I''d point out that the two approaches above are known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of students, and the two characteristics ...”
September 22, 2018
Brent@GMATPrepNow posted a reply to The shaded region in the figure above represents a in the Problem Solving forum
“IMPORTANT: the diagrams in GMAT problem solving questions are DRAWN TO SCALE unless stated otherwise. So, we can use this fact to solve the question by simply "eyeballing" the diagram. See our video below on this topic as well as other assumptions we can make about diagrams on the ...”
September 21, 2018
Brent@GMATPrepNow posted a reply to Challenge question: If ∆ABC is an isosceles triangle in the Data Sufficiency forum
“Target question: What is the perimeter of ∆ABC? Given: ∆ABC is an isosceles triangle Statement 1: AB = 10√3 We only know the measurement of ONE side of the triangle. So, there''s no way to determine the triangle''s perimeter. Since we cannot answer the target question with ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to Challenge question: If ∆ABC is an isosceles triangle in the Data Sufficiency forum
“Thanks Fabio! I fixed it. Cheers, Brent”
September 20, 2018
Brent@GMATPrepNow posted a reply to If Albert can travel 200 miles in 4 hours, how many hours in the Problem Solving forum
“Another approach is to apply some number sense GIVEN: Albert can travel 200 miles in 4 hours This means: Albert can travel 100 miles in 2 hours And: Albert can travel 50 miles in 1 hour 350 miles = 200 miles + 100 miles + 50 miles So, the time to travel 350 miles = 4 hours + 2 hours + 1 ...”
September 20, 2018
beatthegmat posted a reply to 2019 GMAC Official Guide applicable for 60-Day Study Guide? in the The 60-Day GMAT Study Guide forum
“Hi! We have all of the OG questions libraries available here: https://www.beatthegmat.com/official-guide-question-library-t296753.html. Specifically, you can find the OG 2019 question library here: https://www.beatthegmat.com/mba/official-guide-2019-library I hope this helps!”
September 20, 2018
Brent@GMATPrepNow posted a reply to In four years, Andy will be twice as old as Betsy. How old in the Data Sufficiency forum
“ Given: In four years, Andy will be twice as old as Betsy. Let A = Andy''s PRESENT age Let B = Betsy''s PRESENT age So, A+4 = Andy''s age IN 4 YEARS And so, B+4 = Betsy''s age IN 4 YEARS If Andy will be twice as old as Betsy IN 4 YEARS, we can write: A+4 = 2(B+4) Expand: A + 4 = 2B + 8 ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to What is the perimeter of a rectangle? in the Data Sufficiency forum
“Target question: What is the perimeter of a rectangle? This is a good candidate for rephrasing the target question. Let x = the length of the rectangle''s base Let y = the length of the rectangle''s height So, the perimeter of the rectangle = 2x + 2y REPHRASED target question: What is the ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to How many multiples of 33 lie between 101 and 1,000, inclusiv in the Problem Solving forum
“Another approach is to apply the following rule: If x and y are multiples of k, then the number of multiples of k from x to y inclusive = So, for example, the multiples of 3 from 6 to 21 inclusive = 6 So, the number of multiples of 33 from 132 to 990 inclusive = (990 - 132)/33 + 1 = 858/33 ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to How many multiples of 33 lie between 101 and 1,000, inclusiv in the Problem Solving forum
“Some positive multiples of 33 are: 33, 66, 99, 132, 165, 198,. . . , 957, 990, 1023 So, we want the number of multiples of 33 from 132 to 990 inclusive Observe: 132 = (33)(4) 165 = (33)(5) 198 = (33)(6) . . . 957 = (33)(29) 990 = (33)(30) We can see that the number of multiples of ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to Last year's receipts from the sale of candy on Valentine's in the Problem Solving forum
“GIVEN: 385 million dollars represents 7% of TOTAL candy sales In other words: 7% of TOTAL candy sales = 385 million dollars Rewrite as: (7/100)(TOTAL candy sales) = 385 million To multiply both sides by 100/7 to get: TOTAL candy sales = (100/7)(385 million) ASIDE: We need not perform any ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to In the coordinate plane, line M travels through points in the Problem Solving forum
“KEY CONCEPT: In a straight line with slope m, any segment of the line will have slope m. To get from point (9, 10) to point (0, 4), we start at (9, 10) and move 9 spaces to the left and 6 spaces down to get to (0, 4) Let''s keep going. Starting at (0, 4), we can, once again, move 9 spaces ...”
September 20, 2018
Brent@GMATPrepNow posted a reply to If x and y are different prime numbers, each greater than 2, in the Problem Solving forum
“Some important rules: #1. ODD +/- ODD = EVEN #2. ODD +/- EVEN = ODD #3. EVEN +/- EVEN = EVEN #4. (ODD)(ODD) = ODD #5. (ODD)(EVEN) = EVEN #6. (EVEN)(EVEN) = EVEN If x and y are different prime numbers, each greater than 2 . . . Since all prime numbers (EXCEPT 2) are ODD, this statement ...”
September 19, 2018
Brent@GMATPrepNow posted a reply to How many 3 digit numbers can we make such that two of the in the Problem Solving forum
“There are 3 cases to consider: case 1) numbers of the form XXY (1st and 2nd digits are the same and the 3rd digit is different) case 2) numbers of the form XYX (1st and 3rd digits are the same and the 2nd digit is different) case 3) numbers of the form YXX (2nd and 3rd digits are the same and the ...”
September 19, 2018
Brent@GMATPrepNow posted a reply to In 2001, John invest x dollars ina special account that in the Problem Solving forum
“ John $250 in his account in 2006 and in 2008 he has$270 in his account, So, in 2 years, John''s balance increases by $20 So, the balance increases$10 EACH YEAR In 2001, John invests x dollars in a special account that yields y% simple interest annually John''s balance increases $10 EACH ...” September 19, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide - Probability googly in the Problem Solving forum “P(selecting a sibling pair) = P(select a junior with a sibling AND select the senior who is that junior''s sibling) = P(select a junior with a sibling) x P(select the senior who is that junior''s siblingx 1/800 = 60/800,000 = 3/40,000 = A Note: P(select a junior with a sibling) = 60/1000, ...” September 19, 2018 Brent@GMATPrepNow posted a reply to Which of the following decribes all values of n for which in the Problem Solving forum “Another approach is to test values and eliminate answer choices For example, one value of n that satisfies the equation n² - 1 ≥ 0 is n = 2 Notice that 2² - 1 = 4 - 1 = 3 and 3 ≥ 0 Now check the answer choices. . . Answer choice B says that n CANNOT equal 2 (since it says n ≤ 1) As ...” September 19, 2018 Brent@GMATPrepNow posted a reply to In the figure above, what is the distance from point P to in the Problem Solving forum “Once we create our right triangle with sides 1/2, 1/2 and x (the hypotenuse), we can apply the Pythagorean Theorem to get: (1/2)² + (1/2)² = x² Expand: 1/4 + 1/4 = x² So, 1/8 = x² This means x = √(1/8) Check the answer choices. . . .√(1/8) is not there. Looks like we need to simplify ...” September 19, 2018 Brent@GMATPrepNow posted a reply to If six coins are flipped simultaneously, the probability of in the Problem Solving forum “When it comes to probability questions involving "at least," it''s best to try using the complement. That is, P(Event A happening) = 1 - P(Event A not happening) So, here we get: P(getting at least one heads and at least one tails) = 1 - P(not getting at least one heads and at least one ...” September 19, 2018 Brent@GMATPrepNow posted a reply to If n is an integer, is n(n+2) divisible by 8? in the Data Sufficiency forum “Target question: Is n(n+2) divisible by 8? Statement 1: n is an even number. Let''s examine some CONSECUTIVE even numbers: 6, 8, 10, 12, 14, 16, 18, 20, 22, etc Notice that the numbers increase by 2 with each subsequent value. So, if n is EVEN, then we know that n+2 is also even. Also, ...” September 19, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: If ∆ABC is an isosceles triangle in the Data Sufficiency forum “If ∆ABC is an isosceles triangle, what is the perimeter of ∆ABC? (1) AB = 10√3 (2) AC = 8 Answer: C Difficulty level: 600 - 650 Source: www.gmatprepnow.com” September 19, 2018 beatthegmat started following OWN September 19, 2018 beatthegmat started following kdailey September 19, 2018 beatthegmat started following ankit_dhingra7 September 19, 2018 Brent@GMATPrepNow posted a reply to Challenge question: If 40 percent more than 40 percent of x in the Problem Solving forum “--------ASIDE-------------------- 40% MORE THAN k = k + (40% of k) = k + 0.4x = 1.4x 40% LESS THAN Q = Q - (40% of Q) = Q - 0.4Q = 0.6Q ----NOT ONTO THE QUESTION!!----------- 40 percent of x is the same as 0.4x So, 40 percent more than 40 percent of x is the same as (1.4)(0.4x) ...” September 18, 2018 Brent@GMATPrepNow posted a reply to In how many ways a cricket team consisting of 5 batsmen, 4 in the Problem Solving forum “Take the task of creating a cricket team and break it into stages. Stage 1: Select 5 batsmen Since the order in which we select the batsmen does not matter, we can use combinations. We can select 5 batsmen from 7 batsmen in 7C5 ways (21 ways) So, we can complete stage 1 in 21 ways ...” September 18, 2018 Brent@GMATPrepNow posted a reply to Which of the following functions satisfies f(a+b)=f(a)f(b) f in the Problem Solving forum “Another approach is to a = 1 and b = 1 So, with each function, is it true that f(1 + 1) = f(1)f(1)? In other words, is it true that f(2) = f(1)f(1)? A. f(x) = x + 1 Is it true that f(2) = f(1)f(1)? Plug values into the function to get: 2 + 1 = (1 + 1)(1 + 1) Simplify: 3 = 4 No good. ...” September 18, 2018 Brent@GMATPrepNow posted a reply to a and b are positive numbers. What is the value of (a-b)/(a+ in the Data Sufficiency forum “Target question: What is the value of (a - b)/(a + b)? Statement 1: a = 2b Take: (a - b)/(a + b) Replace a with 2b to get: (2b - b)/(2b + b) Simplify: b/3b Divide top and bottom by b to get: 1/3 So, the answer to the target question is (a - b)/(a + b) = 1/3 Since we can answer the ...” September 18, 2018 Brent@GMATPrepNow posted a reply to Which of the following functions satisfies f(a+b)=f(a)f(b) f in the Problem Solving forum “Upon scanning the answer choices, we might recognize that answer choice E, f(x) = 2^x, involves a variable exponent and that the given information that f(a+b) = f (a)f(b) looks A LOT like the Product Law: (k^a)(k^b) = k^(a+b) So, let''s check E first. E. f(x) = 2^x If f(x) = 2^x, then f(a) = ...” September 18, 2018 Brent@GMATPrepNow posted a reply to A certain business school has a student body of 2,000 studen in the Data Sufficiency forum “I thought I''d point out that Jay''s approach is also known as the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of students, and the two characteristics are: ...” September 18, 2018 Brent@GMATPrepNow posted a reply to Going in to the last game of his basketball season, Adrian in the Problem Solving forum “Let G = total number of games that Adrian played in the ENTIRE season Going in to the last game of his basketball season, Adrian had averaged 24 points per game. At this point, Adrian has played G-1 games So, we can write: (total number of points in G-1 games)/(G-1) = 24 Multiply both sides ...” September 17, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: If 40 percent more than 40 percent of x in the Problem Solving forum “If 40 percent more than 40 percent of x is equal to 40 percent less than y, what is the value of x/y? A) 3/8 B) 15/16 C) 1 D) 15/14 E) 15/4 Answer: D Difficulty level: 600 – 650 Source: www.gmatprepnow.com” September 17, 2018 Brent@GMATPrepNow posted a reply to What is the perimeter of isosceles triangle LMN? 1) Side LM in the Data Sufficiency forum “Target question: What is the perimeter of isosceles triangle LMN? Jump to. . . . Statements 1 and 2 combined There are two triangles that satisfy BOTH statements. They are: Case a: The side lengths of triangle LMN are 4, 4 and 4√2. In this case, the answer to the target question is ...” September 17, 2018 Brent@GMATPrepNow posted a reply to 2^p/2^q=? in the Data Sufficiency forum “Target question: What is the value of (2^p)/(2^q) ? This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: Take: (2^p)/(2^q) Apply the Quotient law to get: 2^(p - q) This means (2^p)/(2^q) = 2^(p - q) So, in order ...” September 17, 2018 Brent@GMATPrepNow posted a reply to Counting question in the Ask the Test Maker forum “Good catch! (someone else just alerted me to my error) I have edited my response accordingly. Cheers, Brent” September 17, 2018 Brent@GMATPrepNow posted a reply to If 4x − 3y = 13 and 5x + 2y = −1, then x = in the Problem Solving forum “Given: 4x − 3y = 13 5x + 2y = −1 Take the top equation and multiply both sides by 2 Take the bottom equation and multiply both sides by 3 We get: 8x − 6y = 26 15x + 6y = −3 Add the two equations to get: 23x = 23 Solve: x = 1 Answer: C Cheers, Brent” September 17, 2018 Brent@GMATPrepNow posted a reply to If the ratio of the present age of Anna and Paula is 3:4 in the Problem Solving forum “Here''s a nice property of fractions: If a, b and k are positive, then (a + k)/(b + k) approaches 1 as k gets bigger. For example, the fraction (2+11)/(3+11) is closer to 1 than 2/3 is. Likewise, the fraction (1+7)/(2+7) is closer to 1 than 1/2 is. Let A = Anna''s present age Let P = Paula''s ...” September 16, 2018 Brent@GMATPrepNow posted a new topic called If x^y = 1 then what is the in the Data Sufficiency forum “If x^y = 1, then what is the value of x? (1) x < 0 (2) y is even integer” September 16, 2018 Brent@GMATPrepNow posted a reply to When Leo imported a certain item, he paid a 7 percent import in the Problem Solving forum “Here''s a step-by-step algebraic solution. Let T = the TOTAL value of the item. Leo paid a 7% import tax on the portion of the total value of the item in EXCESS of$1000 So, Leo pays tax on the amount that''s GREATER then $1000 So, Leo pays 7% tax on (T - 1000) We can write: import tax = ...” September 16, 2018 Brent@GMATPrepNow posted a reply to A rectangular-shaped carpet remnant that measures x feet in the Problem Solving forum “Area of rectangle = (base)(height) = (x feet)(y feet) = xy square feet GIVEN: 9 square feet = 1 square yard So, we can also say that 1 square foot = 1/9 square yards So, xy square feet = xy/9 square YARDS So, if xy/9 square YARDS cost$50, then each square YARD = $50/(xy/9) = ...” September 16, 2018 Brent@GMATPrepNow posted a reply to Bob drives at an average rate of 50 mph from Berkeley to Los in the Problem Solving forum “As the others have shown, the fast approach is to recognize that: travel time = distance/speed = 350/50 = 7 hours However, we could also (if necessary) solve this by applying some common sense. Bob''s speed is 50 miles per hour. In other words, for every 1 hour that elapses, Bob travels 50 ...” September 16, 2018 Brent@GMATPrepNow posted a reply to At what speed was Erik running when he was at the halfway in the Data Sufficiency forum “IMPORTANT: The two statements essentially provide the exact same information. If it took Erik 2 hours to travel 10 miles, we can conclude that his average speed was 5 miles per hour. When the two statements provide the same information in a Data Sufficiency question, the correct answer must be ...” September 15, 2018 Brent@GMATPrepNow posted a reply to Probability from GMAT prep in the Problem Solving forum “The two approaches shown above are the best (faster) approaches, but here''s one more. Since there are so few objects involved (5 apples), we should be able to quickly answer the question by simply listing and counting Let A, B, C, D, and E represent the 5 apples, and let E represent the ...” September 15, 2018 Brent@GMATPrepNow posted a reply to A zebra must get water from either a stream or pond. Which in the Data Sufficiency forum “Even if the zebra''s speed is the same in both cases, we can''t conclude anything about the distances, since we aren''t told anything about the direction the zebra is traveling. It may even be the case that the zebra is traveling in circles :-) Cheers, Brent” September 14, 2018 Brent@GMATPrepNow posted a reply to A zebra must get water from either a stream or pond. Which in the Data Sufficiency forum “Target question: Which of the two sources of water is closer to the zebra’s current position? Jump straight to.... Statements 1 and 2 COMBINED There are several scenarios that satisfy BOTH statements. Here are two: Case a: When traveling to the STREAM, the zebra heads EAST in a ...” September 14, 2018 Brent@GMATPrepNow posted a reply to Taking the GMAT in four days. Need advice calming my nerves in the GMAT Strategy forum “You''re certainly not the first person to get nervous during this high-stakes (and expensive) test! If you''re interested, we have a free video on the topic on overcoming test anxiety: [url]http://www.gmatprepnow.com/module/general-gmat-strategies/video/1252[/url] Also, as part of managing ...” September 14, 2018 Brent@GMATPrepNow posted a reply to If 1/n(n+1) = 1/n – 1/(n+1), then what is the value of 1/( in the Problem Solving forum “If 1/n(n+1) = 1/n – 1/(n+1), then... 1/(1*2) = 1/1 - 1/2 1/(2*3) = 1/2 - 1/3 1/(3*4) = 1/3 - 1/4 . . . 1/(98*99) = 1/98 - 1/99 1/(99*100) = 1/99 - 1/100 So, 1/(1*2) + 1/(2*3) + 1/(3*4) + … + 1/(99*100) = (1/1 - 1/2) + (1/2 - 1/3) + (1/3 - 1/4) + . . . (1/98 - 1/99) + (1/99 - ...” September 14, 2018 Brent@GMATPrepNow posted a reply to Is x < 0? in the Data Sufficiency forum “Target question: Is x < 0? Statement 1: |x| = -x Let''s TEST some values. There are several values of x that satisfy statement 1. Here are two: Case a: x = -1. Notice that |-1| = -(-1). In this case, the answer to the target question is YES, x IS less than 0 Case b: x = 0. Notice that ...” September 14, 2018 Brent@GMATPrepNow posted a reply to If n is an integer, is (n+1)^2 an even integer? in the Data Sufficiency forum “Some important rules: 1. ODD +/- ODD = EVEN 2. ODD +/- EVEN = ODD 3. EVEN +/- EVEN = EVEN 4. (ODD)(ODD) = ODD 5. (ODD)(EVEN) = EVEN 6. (EVEN)(EVEN) = EVEN Target question: Is (n+1)² an even integer? This is a good candidate for rephrasing the target question. Aside: Here’s a video ...” September 13, 2018 Brent@GMATPrepNow posted a reply to Jack bought five mobiles at an average price of$150. The in the Problem Solving forum
“Jack bought five mobiles at an average price of $150. So, (sum of all 5 mobiles)/5 =$150 Multiply both sides by 5 to get: sum of all 5 mobiles = $750 The median of all the prices is$200. Let a = smallest value Let b = 2nd smallest value Let d = largest value Let c = 2nd largest value ...”
September 13, 2018
Brent@GMATPrepNow posted a reply to A driver paid n dollars for auto insurance for the year in the Problem Solving forum
“First recognize that INCREASING a value by p percent is the same as multiplying by (100 + p)/100 For example, increasing a value by 7% is the same as multiplying by (100 + 7)/100 Likewise, increasing a value by 25% is the same as multiplying by (100 + 25)/100 Also, recognize that DECREASING a ...”
September 13, 2018
Brent@GMATPrepNow posted a reply to To furnish a room in a model home, an interior decorator is in the Problem Solving forum
“Total # of combinations = (# of ways to select 2 chairs)(# of ways to select 2 tables) So, 150 = (# of ways to select 2 chairs)(# of ways to select 2 tables) # of ways to select 2 chairs 5 tables, choose 2 of them. Since the order of the selected chairs does not matter, we can use ...”
September 13, 2018
Brent@GMATPrepNow posted a reply to How many positive two-digit numbers yield a remainder of 1 in the Problem Solving forum
“When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k are: 1, 1+5, 1+(2)(5), 1+(3)(5), ...”
September 13, 2018
Brent@GMATPrepNow posted a reply to good farming (OG13 71) in the Sentence Correction forum
“(A) good growing conditions both encouraged farming traditions that, in places, endure in The word COMBINATION implies that the two conditions combine to have an effect. So, the word BOTH is redundant. ELIMINATE A (B) good growing conditions encouraged farming traditions that have, in places, ...”
September 12, 2018
Brent@GMATPrepNow posted a reply to What is the biggest positive integer which will always divid in the Problem Solving forum
“One approach is to list integers in the form n, n+1 and n+2 such that n is even, and look for a pattern... 2, 3, 4 Product = 24, which is divisible by 2, 3, 6, 12 and 24 4, 5, 6 Product = 120, which is divisible by 2, 3, 6, 12 and 24 6, 7, 8 Product = 336, which is divisible by 2, 3, 6, ...”
September 12, 2018
Brent@GMATPrepNow posted a reply to If the interior angles of a triangle are in the ratio 3 to in the Problem Solving forum
“Oops, good catch! I have edited my response accordingly. Cheers and thanks, Brent”
September 12, 2018
Brent@GMATPrepNow posted a reply to Flor is choosing three of five colors of paint to use for he in the Problem Solving forum
“Jay''s approach is the approach that I''d typically use. However, it''s important to note that, when the answer choices are so small (as they are here), we should also consider the straightforward strategy of listing and counting Let R, B, P, G and Y represent the colors Red, Blue, Purple, Green ...”
September 12, 2018
Brent@GMATPrepNow posted a reply to If the interior angles of a triangle are in the ratio 3 to in the Problem Solving forum
“All 3 angles must add to 180° So, if we divide 180° into 3 angles in the ratio 3 : 4 : 5, we get: 45° : 60° : 75° What is the measure of the largest angle? The largest angle is 75 degrees° Answer: D Cheers, Brent”
September 12, 2018
Brent@GMATPrepNow posted a reply to Is p + pz = p? in the Data Sufficiency forum
“Target question: Is p + pz = p? This is a great candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: Take Is p + pz = p? and subtract p from both sides to get: Is pz = 0? In order for pz to equal 0, it must be the case that ...”
September 12, 2018
Brent@GMATPrepNow posted a reply to A company plans to assign identification numbers to its in the Problem Solving forum
“Take the task of creating the identification numbers and break it into stages. Stage 1: Select the first digit of the identification number The first digit can be 1, 2, 3, 4, 5, 6, 7, 8, or 9 So, we can complete stage 1 in 9 ways Stage 2: Select the second digit of the identification ...”
September 12, 2018
Brent@GMATPrepNow posted a reply to Last week Chris earned x dollars per hour for the first 40 in the Problem Solving forum
“If Chris worked 48 hours, then he was paid 40x dollars for first 40 hours and (8)(22) dollars for the next 8 hours Since Chris earned $816, we can write: 40x + (8)(22) = 816 Simplify: 40x + 176 = 816 Subtract 176 from both sides: 40x = 640 Solve: x = 640/40 = 16 Answer: D Cheers, Brent” September 11, 2018 Brent@GMATPrepNow posted a reply to If x is even integer, which of the following must be an odd in the Problem Solving forum “A quick approach is the plug in a even number for x and see what happens. A super easy number to use us x = 0 We get..... A) (3)(0)/2 = 0, which is NOT odd. ELIMINATE A. B) (3)(0)/2 + 1 = 1, which IS odd. KEEP B. C) (3)(0)² = 0, which is NOT odd. ELIMINATE C. D) (3)(0²)/2 = 0, which ...” September 11, 2018 Brent@GMATPrepNow posted a reply to The perimeter of a rectangular garden is 360 ft. What is the in the Data Sufficiency forum “Great research, Mitch! I can''t imagine there are many official questions that hinge entirely on that one (somewhat esoteric) construct. I mean, for the every question you cited, it doesn''t matter which side we call the length or the width. The correct answer is the same in all cases. It''s ...” September 11, 2018 Brent@GMATPrepNow posted a reply to The perimeter of a rectangular garden is 360 ft. What is the in the Data Sufficiency forum “Interesting. I''ve never heard of that construct. So, for a box with dimensions 3 x 4 x 5, then the side with length 5 is the length? Which dimension is the width? What about cases when the terms base and height are used? Which one is the base? In a way, this reminds me of the times when ...” September 11, 2018 Brent@GMATPrepNow posted a reply to The aerth travels around the sun at a speed of approximately in the Problem Solving forum “Another way to deal with calculating (18.5)(3600) is to use the answer choices to our advantage. First off, there''s a nice rule that says: AB = (2A)(0.5B) This strategy (which is covered in this video: https://www.gmatprepnow.com/module/general-gmat-strategies/video/1113) can sometimes save us ...” September 11, 2018 Brent@GMATPrepNow posted a reply to What is the value of 22C19? in the Problem Solving forum “Good point! I should have mentioned that I use a shortcut for calculating combinations that allows me to perform most calculations in my head. For example, for 22C3, I write the first 3 values of 22! in the numerator, and I write the 3! in the denominator So, 22C3 = (22)(21)(20)/(3)(2)(1) ...” September 11, 2018 Brent@GMATPrepNow posted a reply to What is the value of 22C19? in the Problem Solving forum “When calculating combinations, it''s sometime useful to apply the following rule: nCr = nC(n-r). In other words, "n choose r" is equal to "n choose n - r" So, for example: 10C7 = 10C3 12C9 = 12C3 8C7 = 8C1 etc. Here''s why this property works: Let''s say you have 22 ...” September 11, 2018 Brent@GMATPrepNow posted a reply to The perimeter of a rectangular garden is 360 ft. What is the in the Data Sufficiency forum “To my test-prep colleagues. I have to say that I''m a little surprised by the official answer (D). For statement 2, it could be the case that length = 120 and width = 60, OR it could be the case that length = 60 and width = 120 The assumption here is that the length of a rectangle must be ...” September 11, 2018 Brent@GMATPrepNow posted a reply to Which of the following points could lie in the same quadrant in the Problem Solving forum “Let''s test some coordinates... How about: a = 1 and b = -2. This means the point (a, b) = (1, -2), which is in QUADRANT IV Now plug a = 1 and b = -2 into each answer choice... A) (-b, -a) = -2), -1] = (2, -1), which is also in QUADRANT IV PERFECT! Answer: A Cheers, Brent” September 11, 2018 September 10, 2018 Brent@GMATPrepNow posted a reply to The sum of the ages of Doris and Fred is y years. If Doris in the Problem Solving forum “Let F = Fred''s PRESENT age Doris is 12 years older than Fred. In other words, Doris'' age = F + 12. So, the sum of their ages = F + (F + 12) Simplify to get: sum of their ages = 2F + 12 The sum of the ages = y 2F + 12 = y Now solve for Fred''s age (F). Start with: 2F + 12 = y ...” September 10, 2018 Brent@GMATPrepNow posted a reply to In the figure, ABCD is a square, and all the dots are in the Problem Solving forum “If the vertical or horizontal distance between two adjacent dots is 3 units, then the square has dimensions 12 by 12 So, the area of the ENTIRE SQUARE = (12)(12) = 144 Now, notice that the square is comprised of 32 identical triangles https://i.imgur.com/mHC9rOY.png Since 16 of the triangles ...” September 10, 2018 Brent@GMATPrepNow posted a reply to Is xy>0? in the Data Sufficiency forum “Target question: Is xy > 0? Statement 1: x³y > 0 Since x² is POSITIVE, we can safely divide both sides of the inequality by x² When we do this, we get xy > 0 So, the answer to the target question is YES, xy IS greater than 0 Since we can answer the target question with ...” September 10, 2018 Brent@GMATPrepNow posted a reply to If the circle above has center O and circumference 18π, the in the Problem Solving forum “The circle has circumference 18π circumference = (2)(radius)(π) So, (2)(radius)(π) = 18π Solve to get: radius = 9 So, OR = 9 and OT = 9 Now, we''ll deal with arc RST Here the sector angle = 60° 60°/360° = 1/6 So, the arc RST represents 1/6 of the ENTIRE circle Since the ENTIRE ...” September 10, 2018 Brent@GMATPrepNow posted a reply to Any decimal that has only a finite number of nonzero digits in the Data Sufficiency forum “Target question: Is r/s a terminating decimal? Statement 1: 90 < r < 100 There are several pairs of values that meet this condition. Here are two: Case a: r = 91 and s = 2, in which case r/s = 91/2 = 45.5 = a terminating decimal Case b: r = 91 and s = 3, in which case r/s = 91/3 = ...” September 10, 2018 Brent@GMATPrepNow posted a reply to In a certain pond, 50 fish were caught, tagged, and returned in the Problem Solving forum “We can use equivalent ratios here. We''re told that the proportion of tagged fish in the 50-fish SAMPLE is equal to the the proportion of tagged fish in the ENTIRE pond. So, (# tagged fish in SAMPLE)/50 = (total # tagged fish)/(total # of fish in POND) Let x = # of fish in the entire ...” September 10, 2018 Brent@GMATPrepNow posted a reply to permutation/combination in the Problem Solving forum “This question is a little too ambiguous to be an official GMAT question. Let''s say X, Y and Z represents 3 different songs. Is an album with song X first, song Y second and song Z third considered DIFFERENT FROM an album with song Z first, song X second and song Y third? The answer to this ...” September 9, 2018 Brent@GMATPrepNow posted a reply to Sam's car was fined when he gave Joe and Peter a ride, so in the Problem Solving forum “Hey Mitch, I think you answered the question "What was the cost of the fine?" (which IS, indeed,$48), but we''re asked to determine the dollar amount that Sam paid (= $20). Cheers, Brent” September 9, 2018 Brent@GMATPrepNow posted a reply to On Monday morning a certain machine ran continuously at a un in the Data Sufficiency forum “Here''s a similar question to practice with: https://www.beatthegmat.com/on-wednesday-morning-a-fortune-cookie-machine-ran-t301683.html Cheers, Brent” September 9, 2018 Brent@GMATPrepNow posted a reply to Sam's car was fined when he gave Joe and Peter a ride, so in the Problem Solving forum “Let F = the total cost of the fine Joe paid$3 more than 1/4 of the fine So, F/4 + 3 = the amount Joe paid Peter paid $3 less than 1/3 of the fine So, F/3 - 3 = the amount Peter paid Sam paid$4 less than 1/2 the fine So, F/2 - 4 = the amount Sam paid (amount Joe paid) + (amount Peter ...”
September 8, 2018
Brent@GMATPrepNow posted a reply to What is the area of a triangle with the following vertices in the Problem Solving forum
“Now that you know the technique, you can practice your speed with this one: http://www.beatthegmat.com/coordinate-geometry-t116975.html Cheers, Brent”
September 8, 2018
Brent@GMATPrepNow posted a reply to In the xy-plane, the line k passes through the origin and in the Data Sufficiency forum
“Target question: Is b (the y-coordinate of the point on the line) positive? Given: Line k passes through the origin and through the point (a,b) Statement 1: The slope of line k is negative There are several lines and points that satisfy statement 1. Here are two: Case a: ...”
September 8, 2018
Brent@GMATPrepNow posted a reply to Out of 2 broken TV sets and 6 fixed TV sets in Joe's Fix-My- in the Problem Solving forum
“There are 8 TV''s in total 2 are broken 6 are fixed We want to find P(at least one TV is broken) When it comes to probability questions involving at least, it''s often best to try using the complement. That is, P(Event A happening) = 1 - P(Event A not happening) So, here we get: P(getting ...”
September 8, 2018
Brent@GMATPrepNow posted a reply to what percent were stockholders who were not employees? in the Problem Solving forum
“Let''s use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of attendees, and the two characteristics are: - stockholder ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to Geometry and Angles (My weakness) in the Problem Solving forum
“Here''s an idea of what''s going on.... https://i.imgur.com/Deg4te0.png When we compare the big triangle with the BASE 30-60-90 special triangle (which you must memorize for test day!), we can see that the hypotenuse of the big triangle is 35 times as long as the hypotenuse of the base triangle. ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to Digging in sediments in northern China, evidence has been in the Sentence Correction forum
“Important: When a sentence begins with a with noun modifier (as it does in the above sentence), stop at the comma and ask the question that the modifier raises. So, once we read, Digging in sediments in northern China, we should stop and ask . . . "Who or what was digging in ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to OG City Council Member Q in the Critical Reasoning forum
“PREMISE: Electricity demands increase 1.5% per year PREMISE: No space to build more power plants CONCLUSION: We must use LESS electricity through ordinances Strategy #1: Try to think of an assumption that''s required for the conclusion to logically follow from the premises. Notice that ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to Working simultaneously and independently at an identical con in the Problem Solving forum
“Let''s assign a nice value to x (a value that will work well with all of the numbers 3, 4 and 6. Let''s say x = 24 GIVEN: 4 machines make x units in 6 days This means 4 machines make 24 units in 6 days So, 4 machines make 4 units in 1 day So, 1 machine makes 1 unit in 1 day From here, ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to What is the value of the 2-digit positive integer n if its in the Data Sufficiency forum
“Target question: What is the value of the 2-digit positive integer n Given: Its tens digit is four times its units digit This is VERY LIMITING information. In fact, this tells us that EITHER n = 41 OR n = 82 There are no other possible values of n. Statement 1: n is an even number ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to A refrigerator holds a number of apples, bananas, carrots an in the Data Sufficiency forum
“Be careful. If you feel that the ratio A : B : C : D = 2x : 5x : 3x : 7x, then you''d be able to answer the target question WITHOUT using any statements. Cheers, Brent”
September 7, 2018
Brent@GMATPrepNow posted a reply to Which of the following points is the intersection between in the Problem Solving forum
“KEY CONCEPT: The point of intersection (call P) of the lines y = 3x + 6 and y = -2x - 4 will be such that the x- and y-coordinates of P will satisfy BOTH equations. Since both equations are set equal to y, we can write: 3x + 6 = -2x - 4 Add 2x to both sides: 5x + 6 = - 4 Subtract 6 from both ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to If a mixture of ground meat consists of 2 pounds of veal in the Problem Solving forum
“We can use the WEIGHTED AVERAGE formula: Weighted average of groups combined = (group A proportion)(group A average) + (group B proportion)(group B average) + (group C proportion)(group C average) + ... When we COMBINE the meats, the TOTAL weight = 2 + 5 = 7 pounds. So, veal comprises 2/7 of ...”
September 7, 2018
Brent@GMATPrepNow posted a reply to Last year the price per share of Stock X increased by k in the Problem Solving forum
“One approach is to plug in values. Let $100 be the original price per share of Stock X Choose a "nice" value for k. How about k = 200 So, after a 200% increase, the new price per share =$300 Let $100 be the original earnings per share of Stock X Choose a "nice" ...” September 6, 2018 Brent@GMATPrepNow posted a reply to If 3x + 2y = -2z, what is x? in the Data Sufficiency forum “Target question: What is the value of x? Given: 3x + 2y = -2z Notice that the two statements have the variables all on the left side of the equation. So, let''s rearrange our given equation to look the same. Take: 3x + 2y = -2z Add 2z to both sides to get: 3x + 2y + 2z = 0 Statement ...” September 6, 2018 Brent@GMATPrepNow posted a reply to The selling price of an article is equal to the cost of the in the Data Sufficiency forum “Let C = cost of article Target question: The markup on a certain television set is what percent of the selling price? Statement 1: The markup on the television set is 25 percent of the cost. If C = cost of article, markup = 0.25C Selling price = cost + markup = C + 0.25C = 1.25C So, ...” September 6, 2018 Brent@GMATPrepNow posted a reply to Last year, a certain public transportation system sold an in the Problem Solving forum “The word "closest" suggests that we can use some estimation here. Let''s first estimate the number of tickets sold PER WEEK 41,000 tickets per day on weekdays (5)(41,000) = 205,000 18,000 tickets per day on weekends (2)(18,000) = 36,000 So, total tickets sold PER WEEK = ...” September 5, 2018 Brent@GMATPrepNow posted a reply to In the xy-coordinate system, line k has slope 1/2 and passes in the Problem Solving forum “While a sample size of 28 might not be a large enough to make prove/validate my recommendations, I can tell you that, from my experience, the correct answer to these kinds of questions is typically closer to E than to A. That said, if it were the case that, with this question type, the correct ...” September 5, 2018 Brent@GMATPrepNow posted a reply to In the figure above, what is the perimeter of rectangle ABPQ in the Data Sufficiency forum “Target question: What is the perimeter of rectangle ABPQ? Statement 1: The area of rectangular region ABCD is 3 times the area of rectangular region ABPQ. Since we aren''t given any information regarding ACTUAL lengths, we cannot determine the perimeter of rectangle ABPQ Since we cannot ...” September 5, 2018 Brent@GMATPrepNow posted a reply to The numbers x and y are NOT integers. The value of x is in the Data Sufficiency forum “Target question: The value of x is closest to which integer? Let''s head straight to........... Statements 1 and 2 combined There are several values of x and y that satisfy BOTH statements. Here are two: Case a: x = 2.4 and y = 1.4. These values satisfy both statements. In this case, ...” September 5, 2018 Brent@GMATPrepNow posted a reply to An insurance company sells only one type of health and one in the Data Sufficiency forum “Let H = the number of health insurance policies Let L = the number of life insurance policies Let p = the monthly premium on a life insurance policy So, 80H + pL = 5000 Target question: What is the value of p? Statement 1: The total revenue from health insurance premiums was 4/5 of ...” September 5, 2018 Brent@GMATPrepNow posted a reply to 8 cities, including Memphis, are finalists to be chosen to in the Data Sufficiency forum “Target question: What is the probability that Memphis is not chosen? ASIDE: At first glance, it may seem like we already have enough information the answer the target question. After all, if there are 8 cities, then P(Memphis is chosen) = 1/8, which means Memphis is not chosen) = 7/8, right? ...” September 5, 2018 Brent@GMATPrepNow posted a reply to In the xy-coordinate system, line k has slope 1/2 and passes in the Problem Solving forum “Let''s first determine the equation of line k A quick approach is the write the equation of line k in slope y-intercept form: y = mx + b, where m = slope and b = y-intercept. We''re told that the slope = 0.5 and the point (0,5) tells us that the y-intercept is 5 So, the equation of line k is: ...” September 5, 2018 Brent@GMATPrepNow posted a reply to A certain company assigns employees to offices in such a way in the Problem Solving forum “ASIDE: When the answer choices are small, you should also consider listing and counting Let X, Y and Z be the 3 employees. Let A and B be the 2 offices. We''ll list the possible outcomes as follows: (employees in office A | employees in office B) So, we get: ( XYZ | -- ) ( XY |Z ) ( XZ ...” September 5, 2018 Brent@GMATPrepNow posted a reply to A certain company assigns employees to offices in such a way in the Problem Solving forum “Let X, Y and Z be the 3 employees. Let A and B be the 2 offices. Take the task of assigning the employees and break it into stages. Stage 1: Assign employee X to an office There two options (office A or office B), so we can complete stage 1 in 2 ways Stage 2: Assign employee Y to an ...” September 5, 2018 Brent@GMATPrepNow posted a reply to A baker makes chocolate cookies and peanut cookies. His in the Problem Solving forum “We''re looking for the smallest possible number of chocolate chip cookies. So, let''s start by testing answer choice A A) If we make 7 chocolate chip cookies, then the remaining 88 cookies are peanut cookies. We''re told that peanut cookies are baked in batches of 6 However, 88 is NOT ...” September 4, 2018 Brent@GMATPrepNow posted a reply to If x and y are integers, what is the least possible positive in the Problem Solving forum “Another approach: There''s a nice rule that says: If j, k and d are integers, and j is a multiple of d, and k is a multiple of d, then (j+k) must be a multiple of d 21x is a multiple of 7 (since 21x = 7(3x) 35y is a multiple of 7 (since 35y = 7(5y) Since 21x and 35y are multiples of 7, the ...” September 4, 2018 Brent@GMATPrepNow posted a reply to If x and y are integers, what is the least possible positive in the Problem Solving forum “21x + 35y = 7(3x + 5y) Since x and y are INTEGERS, we know that 3x and 5y are each INTEGERS, which means 3x + 5y equals some integer So, we can write: 21x + 35y = 7(some integer) In other words, 21x + 35y is a multiple of 7 Check the answer choices.....only D is a multiple of 7 Answer: D ...” September 4, 2018 beatthegmat posted a new topic called MBA or Specialized Master’s Degree: Which is Best for You? in the Research MBA Programs forum “When you think business school, you probably think MBA. A Master’s of Business Administration has long been a coveted — and often essential — qualification for business professionals. In recent years, however, the tide has begun to quietly shift, with more business school students than ever ...” September 4, 2018 Brent@GMATPrepNow posted a reply to standard deviation in the Data Sufficiency forum “Target question: Is the standard deviation of the set positive? KEY CONCEPT: If all of the numbers in a set are EQUAL, then the standard deviation = 0 If the numbers in a set are NOT all equal, then the standard deviation > 0 Given: The set consists of a certain number of even integers ...” September 4, 2018 Brent@GMATPrepNow posted a reply to permutation/combination in the Problem Solving forum “Here''s an algebraic solution... Let M = TOTAL number of men (including Mr. Smith) at the party Let W = TOTAL number of women (including Mrs. Smith) at the party Since Mr. Smith does not shake hands with HIMSELF, Mr. Smith shakes hands with M-1 men, and he shakes hands with W women Since ...” September 4, 2018 Brent@GMATPrepNow posted a reply to Andrew has a certain number of coins in his pocket. He has in the Problem Solving forum “Let x = number of QUARTERS in pocket So, 0.25x = VALUE of quarters in pocket He has three times as many dimes as quarters So, 3x = number of DIMES in pocket So, 0.10(3x) = 0.3x = VALUE of dimes in pocket He has six times as many nickels as dimes. So, (6)(3x) = number of NICKELS in ...” September 4, 2018 Brent@GMATPrepNow posted a reply to Triathlete Dan runs along a 2-mile stretch of river and then in the Problem Solving forum “Average speed = (total distance)/(total time) We know the total distance = 4 miles The total time consists of two parts: Let''s begin with a "word equation" TOTAL time = (time spent running) + (time spent swimming) time = distance/speed So, time spent running = 2/10 = 1/5 hours ...” September 4, 2018 Brent@GMATPrepNow posted a reply to At a garage sale, all of the prices of the items sold were in the Problem Solving forum “The price of the radio was the 15th highest price So, there were 14 items that were more expensive than the radio. In other words, if we listed all of the prices in ascending order, we''d get something like: ........... radio, X, X, X, X, X, X, X, X, X, X, X, X, X, X The price of the radio ...” September 4, 2018 Brent@GMATPrepNow posted a reply to The average television prime-time advertising unit of 30 in the Problem Solving forum “We can also quickly solve this question by testing the answer choices.... Start with C (40%) 40% of$30,000 = $12,000 So, a 40% increase (from 1973 to 1977) =$30,000 + $12000 =$42,000 No good. We need to new amount to be $50,000 ELIMINATE C Since$42,000 is less than $50,000, we need a ...” September 4, 2018 Brent@GMATPrepNow posted a reply to Each of the following numbers has a remaider of 2 when in the Problem Solving forum “ASIDE: This is one of those questions that require us to check/test each answer choice. In these situations, always check the answer choices from E to A, because the correct answer is typically closer to the bottom than to the top. For more on this strategy, see my article: ...” September 4, 2018 Brent@GMATPrepNow posted a reply to At a certain hospital, 75% of the interns receive fewer than in the Problem Solving forum “I thought I''d point out that Mitch''s Double Matrix approach can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of interns, and the two characteristics are: - less than 6 hours sleep or 6 or more ...” September 4, 2018 Brent@GMATPrepNow posted a reply to DS_Arithmetic in the Data Sufficiency forum “Target question: What is the tenth digit in the decimal representation of a certain number? Jump straight to..... Statements 1 and 2 combined Statement 1 tells us that the number is less than 1/3 (aka 0.333333....) Statement 2 tells us that the number is greater than 1/4 (aka 0.25) ...” September 4, 2018 Brent@GMATPrepNow posted a reply to permutation/combination in the Problem Solving forum “This question is a little too ambiguous to be a true (official) GMAT question. Does order matter here? For example, is E driving, A in passenger seat, G in middle of back seat, and C in left side of back seat DIFFERENT FROM C driving, A in passenger seat, E in middle of back seat, and G in left ...” September 3, 2018 Brent@GMATPrepNow posted a reply to A store sold 6 bicycles with an average sale price of$1,000 in the Data Sufficiency forum
“Target question: What was the price of the most expensive bicycle? Given: The store sold 6 bicycles with an average sale price of $1,000. This means the SUM of the 6 bikes =$6000 (since $6000/6 bikes =$1000 average) Statement 1: The median price was $1,000. This statement doesn''t ...” September 3, 2018 Brent@GMATPrepNow posted a reply to Alex paid a$12 fee to receive a 10% discount off of the in the Problem Solving forum
“IMPORTANT: If Alex received a 10% discount, then Alex PAID 90% of the cost of the books If Victor received a 15% discount, then Victor PAID 85% of the cost of the books Start with a word equation Total amount Alex paid = Total amount Victor paid We get: $12 + 90% of b =$15 + 85% of b ...”
September 3, 2018
Brent@GMATPrepNow posted a reply to Paula and Sandy were among those people who sold raffle in the Data Sufficiency forum
“Target question: How many of the tickets did Paula sell? Given: Paula and Sandy sold a total of 100 of the tickets Let x = number of tickets that Paula sold This means 100-x = number of tickets that Sandy sold Statement 1: Sandy sold 2/3 as many of the raffle tickets as Paula did. We ...”
September 3, 2018
Brent@GMATPrepNow posted a reply to Six children — A, B, C, D, E, and F — are going to sit i in the Problem Solving forum
“Here are a few similar questions to practice with: - http://www.beatthegmat.com/permutation-t261691.html - http://www.beatthegmat.com/vowels-and-consonants-arrangement-t149946.html - http://www.beatthegmat.com/how-many-possible-orders-t277574.html Cheers, Brent”
September 3, 2018
Brent@GMATPrepNow posted a reply to integers in the Problem Solving forum
“Here''s one way to look at it. Write all of the numbers as 3-digit numbers. That is, 000, 001, 002, 003, .... 998, 999 NOTE: Yes, I have started at 000 and ended at 999, even though though the question asks us to look at the numbers from 1 to 1000. HOWEVER, notice that 000 and 1000 do not ...”
September 1, 2018
Brent@GMATPrepNow posted a reply to How many positive integers less than 2*10^4 are there in in the Problem Solving forum
“In other words, "How many positive integers less than 20,000 are there in which each digit is a prime number?" The prime digits are: 2, 3, 5 and 7 Notice that, using the digits 2, 3, 5 and 7, we cannot create a 5-digit number that''s less than 20,000 So, we must consider 4 possible ...”
September 1, 2018
Brent@GMATPrepNow posted a reply to Each baseball team in a league has a roster of players in in the Problem Solving forum
“There are 2 pitchers for every 3 fielders So, out of every 5 players, there are 2 pitchers. So, in ONE 25-player team, there are 10 pitchers (and 15 fielders) So, if there are 12 teams, and there are 10 pitchers and 15 fielders per team, then... TOTAL number of pitchers = (12)(10 ) TOTAL ...”
September 1, 2018
Brent@GMATPrepNow posted a reply to Which of the following are/is prime? in the Problem Solving forum
“I. 143 143 = (11)(13) Since 143 is NOT prime, we can ELIMINATE C, D and E II. 147 Notice that 147 = 140 + 7 Since 140 is divisible by 7, and 7 is divisible by 7, we know that 147 is divisible by 7. Since 147 is NOT prime, we can ELIMINATE A So, the answer (by the process of elimination) ...”
September 1, 2018
Brent@GMATPrepNow posted a reply to A certain library assesses fines for overdue books as in the Problem Solving forum
“1st day - $0.10 2nd day -$0.20 or $0.40 (double or add$0.30) $0.20 is the lesser amount 3rd day -$0.40 or $0.50 (double or add$0.30) $0.40 is the lesser amount 4th day -$0.80 or $0.70 (double or add$0.30) $0.70 is the lesser amount The correct answer is B Cheers, Brent” August 31, 2018 Brent@GMATPrepNow posted a reply to The Hazelton coal-processing plant is a major employer in in the Critical Reasoning forum “PREMISE: Coal plant will be shut down it it doesn''t upgrade PREMISE: Expensive upgrade will force company to close, UNLESS it receives tax break PREMISE: To PREVENT increase in local unemployment, government may grant tax break IMPORTANT: the government''s goal is to PREVENT an increase in ...” August 30, 2018 Brent@GMATPrepNow posted a reply to Angela has 15 pairs of matched socks. If she loses 7 in the Problem Solving forum “We can also systematically eliminate 4 of the 5 answer choices. Let''s say the 15 PAIRS of socks are as follows: AA, BB, CC, DD, EE, FF, GG, HH, II, JJ, KK, LL, MM, NN, OO Let''s first see what happens if we "lose" 7 unmatched socks. Say, we lose, A, B, C, D, E, F, G We get: A, B, ...” August 30, 2018 Brent@GMATPrepNow posted a reply to What is the range of 10 numbers? in the Data Sufficiency forum “Target question: What is the range of 10 numbers? Statement 1: The average (arithmetic mean) of the 10 numbers is 10 Let''s TEST some values. There are several sets of numbers that satisfy statement 1. Here are two: Case a: the numbers are {10, 10, 10, 10, 10, 10, 10, 10, 10, 10}. In this ...” August 30, 2018 Brent@GMATPrepNow posted a reply to A jar contains 16 red balls and 8 white balls. If 3 balls ar in the Problem Solving forum “There are 24 balls in the jar (before any are removed) P(all 3 balls are white) = P(1st ball is white AND 2nd ball is white AND 3rd ball is white) = P(1st ball is white) x P(2nd ball is white) x P(3rd ball is white) = 8/24 x 7/23 x 6/22 = 1/3 x 7/23 x 3/11 = 7/253 ASIDE: rather than ...” August 30, 2018 Brent@GMATPrepNow posted a reply to Pumping alone at their respective constant rates, one inlet in the Problem Solving forum “Let''s assign a nice value to the volume of the tank. We want a volume that works well with the given information (1/2, 2/3, 3 hours and 6 hours). So, let''s say the tank has a total volume of 18 gallons One inlet pipe fills an empty tank to 1/2 of capacity in 3 hours 1/2 the tank is 9 ...” August 30, 2018 Brent@GMATPrepNow posted a reply to At a constant rate of flow, it take 20 minutes to fill a in the Problem Solving forum “Let''s assign a nice value to the volume of the pool. We want a volume that works well with the given information (20 minutes and 30 minutes). So, let''s say the pool has a total volume of 60 gallons It takes 20 minutes to fill a swimming pool with a LARGE hose In other words, the LARGE hose ...” August 30, 2018 Brent@GMATPrepNow posted a reply to If 4 is one solution of the equation x^2 + 3x + k = 10, in the Problem Solving forum “Let''s first determine the value of k. Since x = 4 is a solution to the equation x² + 3x + k = 10, we know that x = 4 SATISFIES the equation. That is: 4² + 3(4) + k = 10 Evaluate to get: 16 + 12 + k = 10 Solve for k to get: k = -18 So, the ORIGINAL equation is x² + 3x + (-18) = 10 ...” August 30, 2018 Brent@GMATPrepNow posted a reply to In a certain summer school program, there are five periods in the Problem Solving forum “Take the Science, and Science Lab classes and "glue" them together to get the super class "Science-Science-Lab" This ensures that Science Lab immediately follows the Science class So, we now have only 4 classes: English, Math, History and Science-Science-Lab We can arrange ...” August 29, 2018 Brent@GMATPrepNow posted a reply to Is the measure of one of the interior angles of in the Data Sufficiency forum “Target question: Is the measure of one of the interior angles of quadrilateral ABCD equal to 60? Key concept: the 4 angles in a quadrilateral must add to 360 degrees Statement 1: Two of the interior angles of ABCD are right angles. Let''s test some possible cases. There are infinitely ...” August 28, 2018 Brent@GMATPrepNow posted a reply to Solution X, which is 50% alcohol, is combined with solution in the Problem Solving forum “When solving mixture questions, I find it useful to sketch the solutions with the ingredients SEPARATED: https://i.imgur.com/X6UPop8.png Since we want to determine the volume of solution Y needed, let''s... ...let y = volume (in liters) of solution Y needed This means 16 - y = volume (in ...” August 28, 2018 Brent@GMATPrepNow posted a reply to Is xy>0? in the Data Sufficiency forum “Target question: Is xy>0? Statement 1: x + y > 0 This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = 1. In this case, xy = (1)(1) = 1. So, the answer to the target ...” August 28, 2018 Brent@GMATPrepNow posted a reply to When traveling at a constant speed of 32 miles per hour, a in the Problem Solving forum “Let''s see what happens after ONE HOUR of traveling. In ONE hour, the boat will travel 32 miles and will use 24 gallons of fuel So, the fuel consumption rate is 32 miles per 24 gallons Or we can write: fuel consumption rate = 32/24 miles/gallon 32/24 = 4/3 So, the fuel consumption rate = ...” August 28, 2018 Brent@GMATPrepNow posted a reply to Exactly 8 years ago, Jim's son was twice as old as Jim's in the Problem Solving forum “Jim’s son is now 5 years older than his daughter Let D = the daughter''s age NOW So D + 5 = the son''s age NOW This also means that D - 8 = the daughter''s age EIGHT YEARS AGO This also means that D + 5 - 8 = the son''s age EIGHT YEARS AGO Or we can say, D - 3 = the son''s age EIGHT YEARS ...” August 28, 2018 Brent@GMATPrepNow posted a reply to What is the sum of all multiples of 3 between 1 and 200? in the Problem Solving forum “Useful formula: 1 + 2 + 3 + 4 + . . . n = (n)(n + 1)/2 We want to find the sum: 3 + 6 + 9 + 12 + . . . 198 Factor out the 3 to get: 3(1 + 2 + 3 + 4 + . . . 66) Apply formula to get: 3(66)(67)/2 Evaluate to get: 6633 Answer: C Cheers, Brent” August 28, 2018 Brent@GMATPrepNow posted a reply to What is the value of x? in the Data Sufficiency forum “Here''s another way to look at it..... (1) 310x + 562y = 909 We can think of this as the equation of a line. The x- and y-coordinates of all points on the line will satisfy the equation 310x + 562y = 909 Since there are infinitely many points on the line, there are infinitely many possible ...” August 27, 2018 Brent@GMATPrepNow posted a reply to George bought a large electronic item with a 15% off coupon, in the Problem Solving forum “George was SUPPOSED to receive a 15% discount, but he received a 30% discount. So, he should have returned 15% of the original cost. However, the manager asked for half that amount (i.e., 7.5% of the original cost) In other words, 7.5% of the original cost =$40.50 IMPORTANT: at this point, ...”
August 27, 2018
Brent@GMATPrepNow posted a reply to GMAT Prep Problem 3 in the Problem Solving forum
“Here''s the complete question: Let''s first determine the least possible integer. We''ll use the answer choices to help us along... A) Could the smallest value on the card be 3? Well, the next larger integer is 4, and 3 x 4 = 12, which is OUTSIDE the given range of 15 to 200 So, we ...”
August 27, 2018
Brent@GMATPrepNow posted a reply to GMAT Prep Problem 1 in the Problem Solving forum
“Here''s another algebraic approach. Let M = Alice''s monthly take home pay Let f = the fraction we''ll use to calculate monthly savings The means that fM = the amount of $Alice saves each month. And this means that her annual savings = 12fM Important: If f = the fraction used to ...” August 27, 2018 Brent@GMATPrepNow posted a reply to If m and n are integers greater than 1, is m^n>500? in the Data Sufficiency forum “Target question: Is m^n > 500? Given: m and n are integers greater than 1 Statement 1: n > 8 We''re told that m and n are integers greater than 1 So, the SMALLEST possible value of m is 2 And, if n > 8, the SMALLEST possible value of n is 9 When we plug in these SMALLEST ...” August 27, 2018 Brent@GMATPrepNow posted a reply to If x and y are positive integers and xy=36, what is the smal in the Problem Solving forum “Since there aren''t many PAIRS of integers that have a product of 36, we can simply list the possibilities: x = 1 and y = 36. Here, the SUM = 37 x = 2 and y = 18. Here, the SUM = 20 x = 3 and y = 12. Here, the SUM = 15 x = 4 and y = 9. Here, the SUM = 13 x = 6 and y = 6. Here, the SUM = 12 ...” August 27, 2018 Brent@GMATPrepNow posted a reply to For which of the following functions is f(a+b) = F(a) + f(b) in the Problem Solving forum “One approach is to plug in numbers. Let''s let a = 1 and b = 1 So, the question becomes, "Which of the following functions are such that f(1+1) = f(1) + f(1)?" In other words, for which function does f(2) = f(1) + f(1)? A) If f(x)=x², does f(2) = f(1) + f(1)? Plug in to get: 2² ...” August 27, 2018 Brent@GMATPrepNow posted a reply to If n = 10^10 and n^n = 10^d, what is the value of d? A. 10^ in the Problem Solving forum “A slightly different approach.... Given: n = 10^10 Also given: n^n = 10^d Replace n in the base with 10^10 to get: (10^10)^n = 10^d Apply Power of a Power rule on left side to get: 10^10n = 10^d So, we can conclude that 10n = d Now replace the remaining n with 10^10 to get: 10(10^10) = d ...” August 26, 2018 Brent@GMATPrepNow posted a reply to If it takes Jacob x hours to complete a project and it in the Problem Solving forum “For work questions, there are two useful rules: Rule #1: If a person can complete an entire job in k hours, then in one hour, the person can complete 1/k of the job Example: If it takes Sue 5 hours to complete a job, then in one hour, she can complete 1/5 of the job. In other words, her work ...” August 25, 2018 Brent@GMATPrepNow posted a reply to Each of the following numbers has a remaider of 2 when in the Problem Solving forum “A. 2 divided by 11 equals 0 with remainder 2. ELIMINATE B. 13 divided by 11 equals 1 with remainder 2. ELIMINATE C. 24 divided by 11 equals 2 with remainder 2. ELIMINATE D. 57 divided by 11 equals 5 with remainder 2. ELIMINATE By the process of elimination, the correct answer MUST be E Let''s ...” August 25, 2018 Brent@GMATPrepNow posted a reply to If each of the two digits X and Y is distinct in the Data Sufficiency forum “Target question: Is the two-digit integer xy prime? Given: Each of the two digits x and y is distinct Statement 1: Each of the digits x and y is the sum of 2 distinct single digit prime numbers. Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here ...” August 25, 2018 Brent@GMATPrepNow posted a reply to Is w less than y? in the Data Sufficiency forum “Target question: Is w less than y? Statement 1: 1.3 < w < 1.3101 Since we have no information about y, there''s no way to determine whether w is less than y Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: 1.3033 < y Since we ...” August 25, 2018 Brent@GMATPrepNow posted a reply to What is the sum of all of the integers in the chart above? in the Problem Solving forum “Always check the answer choices BEFORE solving the question!! Since the answer choices are nicely spread apart, we can be quite aggressive in our estimation Let''s add the 5 numbers in each COLUMN COLUMN 1: Sum ≈500 COLUMN 2: Sum ≈-1000 COLUMN 3: Sum ≈1500 COLUMN 4: Sum ≈-2000 ...” August 25, 2018 Brent@GMATPrepNow posted a reply to After receiving a 25% discount, Amanda pays$240 for a TV. in the Problem Solving forum
“Another approach is to TEST THE ANSWER CHOICES.... If Amanda received a 25% discount, then she paid 75% of the original price. In other words, she paid 3/4 of the original price. We''re told she paid $240, so we''ll check the answer choices to see which one yields an output of$240 when we ...”
August 25, 2018
Brent@GMATPrepNow posted a reply to After receiving a 25% discount, Amanda pays $240 for a TV. in the Problem Solving forum “Let x = the original price (BEFORE the discount) If Amanda received a 25% discount, then she paid 75% of the original price. In other words, she paid 75% of x We''re told she paid$240, so we can write: 75% of x = $240 Or we can write: 0.75x = 240 ASIDE: One approach here is to divide ...” August 25, 2018 Brent@GMATPrepNow posted a reply to A gambler rolls three fair six-sided dice. What is the in the Problem Solving forum “Let''s first calculate P(same, same, different) P(same, same, different) = P(1st roll is ANY value AND 2nd roll matches 1st roll AND 3rd roll is different from first 2 rolls) = P(1st roll is ANY value) x P(2nd roll matches 1st roll) x P(3rd roll is different from first 2 rolls) = 6/6 x 1/6 x 5/6 ...” August 25, 2018 Brent@GMATPrepNow posted a reply to Michael drives x miles due north at arrives at Point A. He in the Problem Solving forum “At the risk of being that guy, I believe the answer is E. Here''s why: We already know that, if we start at a place on the equator and walk 40,000 km (the approximate circumference of Earth) due east, we will end up at the same place we started. If we start at a place further north (say Los ...” August 25, 2018 Brent@GMATPrepNow posted a reply to f 412*378 = A, then which of the following is equal to 412*3 in the Problem Solving forum “Given: (412)(378) = A We must find the value of (412)(379). (412)(379) = (412)(378 + 1) = (412)(378) + (1)(412) = A + 412 Answer: D Cheers, Brent” August 24, 2018 Brent@GMATPrepNow posted a reply to If the sales tax on a$12.00 purchase is $0.66, what is the in the Problem Solving forum “We can also solve this question using equivalent ratios We''re comparing sales tax to retail price We get: sales tax/retail price =$0.66/$12.00 What is the sales tax on a$20.00 purchase? Let x = the sales tax We can write: $0.66/$12.00 = x/$20.00 Cross multiply to get: (0.66)(20) = ...” August 24, 2018 Brent@GMATPrepNow posted a reply to At a bowling alley, Neil can win a free pair of bowling in the Problem Solving forum “At a bowling alley, Neil can win a free pair of bowling shoes if he averages a score of at least 200 over 8 games. If the average of the 8 games = 200, then we can write: (sum of all 8 scores)/8 = 200 Multiply both sides by 8 to get: sum of all 8 scores = 1600 If his scores in his first seven ...” August 24, 2018 Brent@GMATPrepNow posted a reply to Last month, a florist gave 7 percent of her sales revenue to in the Problem Solving forum “Choose a "nice" number for the sales revenue Let$100 = LAST MONTH''s revenue So, $120 = THIS MONTH''s revenue (since sales were up 20 percent from last month) LAST month, a florist gave 7 percent of her sales revenue to her employees in bonuses So, bonuses = 7% of$100 = $7 ...” August 24, 2018 Brent@GMATPrepNow posted a reply to A librarian has a set of ten books, including four different in the Problem Solving forum “Let''s first "glue" the 4 Lincoln books together to create one SUPER BOOK (this will ensure that the 4 books remain together) We now have 7 books: 6 regular books and 1 super book We can arrange these 7 books in 7! ways. KEY: For each of the 7! arrangements, we can take the 4 Lincoln ...” August 24, 2018 Brent@GMATPrepNow posted a reply to If n is a positive integer, which of the following can’t b in the Problem Solving forum “KEY CONCEPTS: #1) If n is an integer, then n and n+1 are consecutive integers #2)If n and n+1 are consecutive integers, then one value is ODD and the other value is EVEN #3)ODD^4 = (ODD)(ODD)(ODD)(ODD) = ODD #4)EVEN^4 = (EVEN)(EVEN)(EVEN)(EVEN) = EVEN #5)(odd)-(odd) = even #6)(odd)-(even) = ...” August 24, 2018 Brent@GMATPrepNow posted a reply to The average (arithmetic mean) of the five numbers in a data in the Problem Solving forum “Let a, b, c, d and e be the five numbers in the set. The average (arithmetic mean) of the five numbers in a data set is 72. So, (a + b + c + d + e)/5 = 72 Multiply both sides of the equation by 5 to get: a + b + c + d + e = 360 The average (arithmetic mean) of the first three numbers is ...” August 24, 2018 Brent@GMATPrepNow posted a reply to What is the length of the sides of a given cube? in the Data Sufficiency forum “IMPORTANT: For geometry Data Sufficiency questions, we are typically checking to see whether the statements "lock" a particular angle, length, or shape into having just one possible measurement. This concept is discussed in much greater detail in the following video: Target question: What ...” August 23, 2018 Brent@GMATPrepNow posted a reply to A whole number greater than 1 has remainders of 1 when it is in the Problem Solving forum “Let N = the number in question. If N divided by 2 leaves a remainder of 1, then N is 1 greater than some multiple of 2. This means that N - 1 must be a multiple of 2. Likewise, if N divided by 3 leaves a remainder of 1, then N is 1 greater than some multiple of 3. This means that N - 1 ...” August 23, 2018 Brent@GMATPrepNow posted a reply to If n is the smallest integer such that 432 times n is the in the Problem Solving forum “IMPORTANT CONCEPT: The prime factorization of a perfect square (the square of an integer) will have an even number of each prime For example: 400 is a perfect square. 400 = 2x2x2x2x5x5. Here, we have four 2''s and two 5''s This should make sense, because the even numbers allow us to split the ...” August 23, 2018 Brent@GMATPrepNow posted a reply to United Telephone charges a base rate of$10.00 for service, in the Problem Solving forum
“Let x = the number of minutes used United Telephone charge = $10.00 +$0.25x Atlantic Call charge = $12.00 +$0.20x For what number of minutes would the bills for each telephone company be the same? In other words, for what value of x does $10.00 +$0.25x EQUAL $12.00 +$0.20x? Let''s ...”
August 23, 2018
Brent@GMATPrepNow posted a reply to Alice, Bob, Cindy, Dave and Eddie joined a three-person-a-si in the Problem Solving forum
“When the answer choices are relatively small (as they are here), we should also consider just [size=150]listing the possible outcomes[/size]. They are: ABC ABD ABE ACD ACE ADE BCD BCE BDE CDE Answer: E Cheers, Brent”
August 22, 2018
Brent@GMATPrepNow posted a reply to If x and y are integers, is x^3+3x-y an even number? in the Data Sufficiency forum
“-----ASIDE------------------------- Some important rules: 1. ODD +/- ODD = EVEN 2. ODD +/- EVEN = ODD 3. EVEN +/- EVEN = EVEN 4. (ODD)(ODD) = ODD 5. (ODD)(EVEN) = EVEN 6. (EVEN)(EVEN) = EVEN ------------------------------------- Target question: Is x³ + 3x - y an even number? ...”
August 22, 2018
Brent@GMATPrepNow posted a reply to Alice, Bob, Cindy, Dave and Eddie joined a three-person-a-si in the Problem Solving forum
“The order in which we select the 3 starters does not matter. For example, selecting Alice then Cindy and then Dave to be the starters is the SAME as selecting Cindy then Dave and then Alice to be the starters. Since order does not matter, we can use COMBINATIONS We can select 3 players from 5 ...”
August 22, 2018
Brent@GMATPrepNow posted a reply to What is the decimal equivalent of (1/5)^5? in the Problem Solving forum
“Another approach: Given: (1/5)^5 Rewrite as: 1/(5^5) Create equivalent fraction by multiplying top and bottom by 2^5 to get: 2^5/(2^5)(5^5) Simplify: 32/10^5 Simplify: 32/100,000 STOP. So, the decimal equivalent will have 32 in. Check the answer choices.....only A works. Answer: ...”
August 22, 2018
Brent@GMATPrepNow posted a reply to What is the decimal equivalent of (1/5)^5? in the Problem Solving forum
“Here''s one approach: (1/5)⁵ = (2/10)⁵ = (2⁵)/(10⁵) = 32/100,000 = 0.00032 = A Cheers, Brent”
August 21, 2018
Brent@GMATPrepNow posted a reply to In the biology lab of "Jefferson" High School ther in the Problem Solving forum
“Germs per dish = (total number of germs)/(total number of dishes) total number of germs = 0.037 x 10^5 = 3700 total number of dishes = 74000 x 10^(-3) = 74 So, Germs per dish = (3700)/(74) = (37)(100)/(37)(2) = 100/2 = 50 Answer: E Cheers, Brent”
August 21, 2018
Brent@GMATPrepNow posted a reply to One machine, working at a constant rate, can fill a certain in the Problem Solving forum
“Let''s assign a "nice" value to the entire job (a value that works well with the given information) Let''s say the machine is making widgets and an order = 8 widgets. One machine, working at a constant rate, can fill a production order in 8 hours. In other words, ONE machine can ...”
August 21, 2018
Brent@GMATPrepNow posted a reply to In the xy-coordinate plane, which of the following points in the Problem Solving forum
“APPROACH #2: Rewrite the equation in slope y-intercept form y = mx + b, where m is the slope of the line and b is the line''s y-intercept Take: kx + 3y = 6 Subtract kx from both sides: 3y = 6 - kx Divide both sides by 3 to get: y = 2 - kx/3 Rewrite as: y = (k/3)x + 2 So, the slope of the ...”
August 20, 2018
Brent@GMATPrepNow posted a reply to In the xy-coordinate plane, which of the following points in the Problem Solving forum
“APPROACH #1: The key here is "for every possible value of k" So, let''s assign a value of k and see what happens. How about k = 0? When k = 0, the equation becomes: (0)x + 3y = 6 Simplify: 3y = 6 Solve: y = 2 So, in this case, the y-coordinate must be 2! Check the answer ...”
August 20, 2018
Brent@GMATPrepNow posted a reply to The median of a data set is x and its maximum is 40. The ran in the Problem Solving forum
“Your suggestion that range = 2(maximum value - median) is not always true In fact, the only time the range = 2(maximum value - median) is when the median is the average of the minimum and maximum value. For example, in the set {1, 9, 17}, the range = 17 - 1 = 16, which is equal to 2(maximum value ...”
August 20, 2018
Brent@GMATPrepNow posted a reply to The median of a data set is x and its maximum is 40. The ran in the Problem Solving forum
“GIVEN: The median of a data set is x, and its MAXIMUM is 40 The range of the set is 10 greater than the median So, the range = x + 10 Let N = the MINIMUM value We can write: MAXIMUM value - MINIMUM value = range Rewrite as: 40 - N = x + 10 What is the minimum of the set in terms of x? ...”
August 20, 2018
Brent@GMATPrepNow posted a reply to Let z be the harmonic mean of x and y. If 1/z=(1/2)((1/x)+ in the Problem Solving forum
“Aside: The GMAT doesn''t expect test-takers to know the term harmonic mean. If there were ever a question involving harmonic mean, the definition of the term would be included. Here''s the definition: https://www.investopedia.com/terms/h/harmonicaverage.asp Cheers, Brent”
August 20, 2018
Brent@GMATPrepNow posted a reply to If (|x|-2)(x-1)=0, then x=? in the Data Sufficiency forum
“Target question: What is the value of x? Given: (|x| - 2)(x - 1) = 0 This tells us that EITHER: |x| - 2 OR x - 1 = 0 If |x| - 2 = 0, then x = 2 OR x = -2 If x - 1 = 0, then x = 1 So, there are 3 possible values of x: i. x = 2 ii. x = -2 iii. x = 1 Statement 1: x > 0 When we ...”
August 20, 2018
Brent@GMATPrepNow posted a reply to For the list of numbers above there is exactly one mode. Is in the Data Sufficiency forum
“Sorry, but I don''t see any numbers above.”
August 19, 2018
Brent@GMATPrepNow posted a reply to A line has a slope of 3/4 and intersects the point (-12, -39 in the Problem Solving forum
“TIP: If you were running short on time and encountered this question, you could quickly eliminate C, D and E and guess between A and B . The coordinates of the x-intercept must be in the form (k, 0). So, we can eliminate C, D and E. Now onto the solution... Let''s write the equation in slope ...”
August 19, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive, what is x+y? in the Data Sufficiency forum
“-------------ASIDE-------------------------------- IMPORTANT: We are not told that x and y are integers. So, they need not be integers! ALSO IMPORTANT: There exists a value of y so that 3^y = 36. How do we know this? Well, 3^3 = 27 and 3^4 = 81 Since 36 is BETWEEN 27 and 81, there must be a ...”
August 19, 2018
Brent@GMATPrepNow posted a reply to For the list of numbers above there is exactly one mode. Is in the Data Sufficiency forum
“I don''t see the list of numbers.”
August 19, 2018
Brent@GMATPrepNow posted a reply to R is the set positive odd integers less than 50, and S is in the Problem Solving forum
“How many elements does the intersection of R as S contain? So, we need to count all values that satisfy both conditions In other words, we need to count all values that are BOTH odd integers less than 50 AND the squares of integers Let''s list possible values: 1² = 1 1 is less than ...”
August 19, 2018
Brent@GMATPrepNow posted a reply to What is the 777th decimal digit of 0.345634563456……..? in the Problem Solving forum
“Look for a pattern... 1st decimal digit: 3 2nd decimal digit: 4 3rd decimal digit: 5 4th decimal digit: 6 5th decimal digit: 3 6th decimal digit: 4 7th decimal digit: 5 8th decimal digit: 6 9th decimal digit: 3 ...etc This pattern repeats itself every 4 digits In other words, the ...”
August 17, 2018
Brent@GMATPrepNow posted a reply to If x, y, and z are positive integers, x=? in the Data Sufficiency forum
“ Given: x, y, and z are positive integers Target question: What is the value of x? Statement 1: y = x + 1, and z = x + 3 There are infinitely many solutions to the above equations, which means there are infinitely many possible answers to the target question. Since we cannot answer the ...”
August 17, 2018
Brent@GMATPrepNow posted a reply to Is x > y? in the Data Sufficiency forum
“Target question: Is x > y? Statement 1: x - y > 3 At first glance, this information APPEARS to be insufficient. However, if we recognize that 3 > 0, then we can add this to the inequality to get: x - y > 3 > 0 From here, we can ignore the 3 to see that: x - y > 0 Add y ...”
August 17, 2018
Brent@GMATPrepNow posted a reply to A certain junior class has 1,000 students and a certain in the Problem Solving forum
“P(selecting a sibling pair) = P(select a junior with a sibling AND select the senior who is that junior''s sibling) = P(select a junior with a sibling) x P(select the senior who is that junior''s siblingx 1/800 = 60/800,000 = 3/40,000 = A Note: P(select a junior with a sibling) = 60/1000, ...”
August 17, 2018
Brent@GMATPrepNow posted a reply to A case contains c cartons. Each carton contains b boxes, and in the Problem Solving forum
“Let''s solve this question by picking some numbers (aka using the INPUT-OUTPUT approach). Let b = 3 and c = 5 So, a case contains 5 cartons. Each carton contains 3 boxes, and each box contains 100 paper clips. So, the number of paper clips in 1 case = (100)(5)(3) = 1500 How many paper ...”
August 16, 2018
Brent@GMATPrepNow posted a reply to Over the course of a single week, the price of a company's in the Problem Solving forum
“Let''s assign a "nice" value to the original price. Let $100 be the original price (BEFORE any increases) Over the course of a single week, the price of a company’s stock rose by 10%. 10% of$100 = $10 So, the NEW price =$100 + $10 =$110 The following week the company’s ...”
August 16, 2018
Brent@GMATPrepNow posted a reply to In a stack of boards at a lumber yard, the 20th board in the Problem Solving forum
“Let''s start from the bottom and work our way up: We''ll start with the 16th board counting from the bottom of the stack Right BELOW that 16th board, we have a board that we''ll call Larry. So, Larry is the 15th board counting from the bottom of the stack. So, starting from the bottom and ...”
August 16, 2018
Brent@GMATPrepNow posted a reply to A rectangular box, with dimesions of 12 inches by 18 inches in the Problem Solving forum
“The question comes down to determining how to orient the box. Do, we make the HEIGHT of the box 12 inches, 18 inches or 10 inches? Well, since the height of each CAN is 5 inches, we can see that making the HEIGHT of the box 10 inches is a great course of action. Otherwise, there will be empty ...”
August 15, 2018
Brent@GMATPrepNow posted a reply to (x – 1)(y – 1) = 1? in the Data Sufficiency forum
“ Given: xy > 0 Target question: Does (x - 1)(y - 1) = 1? This is a good candidate for rephrasing the target question Take the equation: (x - 1)(y - 1) = 1 Use FOIL to expand the left side to get: xy - x - y + 1 = 1 Subtract 1 from both sides to get: xy - x - y = 0 REPHRASED ...”
August 15, 2018
Brent@GMATPrepNow posted a reply to For all real numbers x and y, let x# y = (xy)^2 − x + y^2 in the Problem Solving forum
“APPROACH #2 - Test the answer choices A) 0 Take x#y = (xy)² − x + y², and replace y with 0 We get: 0)]² − x + 0² = 0, x#y = -x PERFECT! Answer: A Cheers, Brent”
August 15, 2018
Brent@GMATPrepNow posted a reply to For all real numbers x and y, let x# y = (xy)^2 − x + y^2 in the Problem Solving forum
“APPROACH #1 We want the following equation to hold true: x # y = –x Replace x # y with its equivalent to get: (xy)² − x + y² = -x Add x to both sides to get: (xy)² + y² = 0 Simplify (xy)² to get: x²y² + y² = 0 Factor out the y² to get: y²(x² + 1) = 0 So, the equation will hold ...”
August 15, 2018
Brent@GMATPrepNow posted a reply to Uncle Bruce is baking chocolate chip cookies. He has 36 in the Problem Solving forum
“We can also use equivalent ratios The cookies will consist of 20% chocolate. In other words, the cookies will consist of 1/5 chocolate. We can also say the cookies will consist of 4/5 dough. This means the cookies are 4 parts dough and 1 part chocolate. So, the dough to chocolate ratio ...”
August 15, 2018
Brent@GMATPrepNow posted a reply to If mn ≠ 0 and 25 percent of n equals in the Problem Solving forum
“Useful conversions: 25% = 1/4 37.5% = 3/8 25 percent of n equals 37(1/2) percent of m In other words, 1/4 of n equals 3/8 of m We get: (1/4)(n) = (3/8)(m) Simplify: n/4 = 3m/8 What is the value of 12n/m? Take n/4 = 3m/8 Cross-multiply to get: (8)(n) = (3m)(4) Simplify: 8n = 12m ...”
August 15, 2018
Brent@GMATPrepNow posted a reply to John sold 100 shares of stock for $96 per share. For half in the Problem Solving forum “Let x be the ORIGINAL price of each share that sold for a 20% PROFIT So, 1.2x = price of each share that sold for a 20% profit In other words, 1.2x =$96 So, x = 96/1.2 = $80 So, these shares ORIGINALLY cost$80 each Let y be the ORIGINAL price of each share that sold for a 20% LOSS So, 0.8x ...”
August 14, 2018
Brent@GMATPrepNow posted a reply to Three printing presses, R, S, and T, working together at the in the Problem Solving forum
“----------ASIDE-------------------- For work questions, there are two useful rules: Rule #1: If a person can complete an entire job in k hours, then in one hour, the person can complete 1/k of the job Example: If it takes Sue 5 hours to complete a job, then in one hour, she can complete 1/5 of ...”
August 14, 2018
Brent@GMATPrepNow posted a reply to Which of the following lines in the xy-plane does not in the Problem Solving forum
“Core concept: If a point (x,y) is on a given line, then the coordinates (x and y) of that point must satisfy the equation of that line. In answer choice B, the equation (y = x + 1/2) tells us that, for ANY POINT ON THE LINE, the y-coordinate will be equal to the x-coordinate plus 1/2 So, if the ...”
August 14, 2018
Brent@GMATPrepNow posted a reply to If a number between 0 and 1 is selected at random, which of in the Problem Solving forum
“Another approach is to convert everything to decimals We need to determine the LENGTH OF EACH INTERVAL. The interval that has the greatest length, will be the most likely interval. To determine the length of each interval, it may be faster to first convert the fractions to decimals. We get: ...”
August 14, 2018
Brent@GMATPrepNow posted a reply to Challenge: If f(3x + 2) = 9x² + 12x - 1, then f(k - 1) = in the Problem Solving forum
“Given: f(3x + 2) = 9x² + 12x - 1 First notice that 9x² + 12x - 1 looks a lot like how (3x + 2)² looks when we expand an simplify it. Notice that (3x + 2)² = 9x² + 12x + 4 This is VERY similar to 9x² + 12x - 1 In fact, if we take 9x² + 12x + 4 and subtract 5, we get 9x² + 12x - 1 That ...”
August 14, 2018
Brent@GMATPrepNow posted a reply to Ben is driving on the highway at x miles per hour. (One mile in the Problem Solving forum
“Here''s an algebraic approach: Each tire has a circumference of y feet. So, there will be 1 revolution every time the car travels y feet. 5280/y = the number of times y divides into 5280. So, if the car travels 5280 feet (aka 1 mile) in one hour, then there will be 5280/y revolutions. If ...”
August 14, 2018
beatthegmat posted a new topic called Prepping for the GMAT Is a Marathon, Not a Sprint in the GMAT Strategy forum
“https://s15.postimg.cc/a2pix60fr/image.png The Graduate Management Admissions Test, or GMAT, is a common admissions requirement for most MBA programs, especially for applicants who don’t have a lot of work experience. The GMAT is a long and difficult exam that tests your command of the English ...”
August 13, 2018
Brent@GMATPrepNow posted a reply to If x is the sum of six consecutive integers, the x is in the Problem Solving forum
“Let''s test some possible values.... The six consecutive integers COULD be 1, 2, 3, 4, 5, 6 So, the SUM = 1 + 2 + 3 + 4 + 5 + 6 = 21 Now check the three statements.... I. 3 21 IS divisible by 3 So, statement 1 is TRUE. ELIMINATE B and C II. 4 21 is NOT divisible by 3 So, ...”
August 13, 2018
Brent@GMATPrepNow posted a reply to A machine at the golf ball factory can produce 16 golf balls in the Problem Solving forum
“Let''s answer the question in steps... GIVEN: 1 machine produces 16 golf balls in 5 minutes. So, 1 machine produces 16/5 golf balls in 1 minute So, 5 machines produce 16 golf balls in 1 minute So, 10 machines produce 32 golf balls in 1 minute Answer: D Cheers, Brent”
August 13, 2018
Brent@GMATPrepNow posted a new topic called Challenge: If f(3x + 2) = 9x² + 12x - 1, then f(k - 1) = in the Problem Solving forum
“If f(3x + 2) = 9x² + 12x - 1, then f(k - 1) = A) k² - 2k - 6 B) k² - 2k - 5 C) k² - 2k - 4 D) k² - 2k + 1 E) k² - 2k + 5 Answer: C Difficulty level: 700+ Source: www.gmatprepnow.com * I''ll post a solution in 2 days”
August 12, 2018
Brent@GMATPrepNow posted a new topic called If f(2x - 1) = 4x² - 4x - 8, then f(5) = in the Problem Solving forum
“If f(2x - 1) = 4x² - 4x - 8, then f(5) = A) 16 B) 18 C) 36 D) 48 E) 72 Answer: A Difficulty level: 600 (ish) Source: www.gmatprepnow.com”
August 12, 2018
Brent@GMATPrepNow posted a reply to Are all of the terms in Set A equal? in the Data Sufficiency forum
“Target question: Are all of the terms in Set A equal? Statement 1: The sum of all 14 terms in Set A is 98 There are several possible scenarios that satisfy this statement. Here are two. Case a: Set A = {7,7,7,7,7,7,7,7,7,7,7,7,7,7} in which case all of the numbers ARE equal Case b: Set A = ...”
August 12, 2018
Brent@GMATPrepNow posted a reply to A box contains only red chips, green chips and blue chips. in the Data Sufficiency forum
“Target question: What is the probability that the chip is either red or green? Given: The box contains only red chips, green chips and blue chips Statement 1: The probability of selecting green chip is 1/3 This tells us that 1/3 of the chips are GREEN, but there''s no information about ...”
August 12, 2018
Brent@GMATPrepNow posted a reply to At a certain university, the dormitory policy is that each in the Problem Solving forum
“One approach is to use equivalent ratios Each dormitory must have at least 7 resident advisers for every 200 residents. So, advisers/residents = 7/200 If a dormitory is home to 3500 residents, what is the minimum number of resident advisers required? Let x = minimum number of advisers We ...”
August 11, 2018
Brent@GMATPrepNow posted a reply to A retailer orders u units of an item for which he pays d in the Problem Solving forum
“A retailer orders u units of an item for which he pays d dollars. So, EACH unit costs d/u dollars However, he mistakenly receives u - 3 items. In other words, he received 3 fewer units than he wanted So, he paid for 3 units that he never received (i.e., he was overcharged for 3 units) How ...”
August 11, 2018
Brent@GMATPrepNow posted a reply to A card game called “high-low” divides a deck of 52 playi in the Problem Solving forum
“Once we recognize that we can achieve 5 points by drawing 3 Low cards and 1 High card, then it really comes down to determining the number of ways to rearrange 3 L''s and 1 H. One option is to simply list the arrangements. Alternatively, we can use the MISSISSIPPI rule, which says: If there are ...”
August 11, 2018
Brent@GMATPrepNow posted a reply to In each game of a certain tournament, a contestant either in the Data Sufficiency forum
“Target question: How many games did Pat play in the tournament? Jump straight to... Statements 1 and 2 combined There are several CONFLICTING situations that that satisfy BOTH statement 2. Here are two: Case a: Pat plays 2 games and wins both of them to add 4 points to the 100 points ...”
August 10, 2018
Brent@GMATPrepNow posted a reply to In a home library consisting of 108 books, some hardcover in the Problem Solving forum
“The concept tested here is the same as is tested in this official GMAT question: https://www.beatthegmat.com/og-help-problem-t286349.html Give it a try. Cheers, Brent”
August 10, 2018
Brent@GMATPrepNow posted a reply to A family consisting of one mother, one father, two daughters in the Problem Solving forum
“Another (slightly longer) approach: The restriction about the sisters is somewhat problematic, so let''s IGNORE the rule and seat all 5 people without obeying that restriction. Then once I determine the total number of arrangements, I''ll subtract the number of arrangements where the sisters ...”
August 10, 2018
Brent@GMATPrepNow posted a reply to How many different 3-digit numbers are greater than 299 and in the Problem Solving forum
“Take the task of creating the 3-digit numbers and break it into stages. Stage 1: Select the first digit (hundreds digit) Since the first digit can be 3, 4, 5, 7 or 9, we can complete stage 1 in 5 ways Stage 2: Select the second digit (tens digit) Since the second digit can be 0, 2, 3, 4, ...”
August 10, 2018
Brent@GMATPrepNow posted a reply to A sports team played 100 games last season. Did this team in the Data Sufficiency forum
“Target question: Did this team win at least half of the games it played last season? Rephrased target question: Did this team win more than 49 games? Statement 1: The team won 60% of its first 65 games In other words, the team won 39 of its first 65 games Since we don''t know the results ...”
August 9, 2018
Brent@GMATPrepNow posted a reply to Problem Solving on Set Theory in the Problem Solving forum
“Another approach is to use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of baseball players, and the two characteristics ...”
August 9, 2018
Brent@GMATPrepNow posted a reply to If the average (arithmetic mean) of a, b and c is m, is thei in the Data Sufficiency forum
“Target question: Is the standard deviation of a, b and c less than 1? Statement 1: a, b and c are consecutive integers with a < b < c. It''s important to know that standard deviation is a measure of dispersion (how spread apart the values are). So, ANY 3 consecutive integers will have ...”
August 8, 2018
Brent@GMATPrepNow posted a reply to Extra practice with ratios: A certain zoo has exactly five in the Problem Solving forum
“The ratio of the number of alligators to buffalo to camels is 4 : 3 : 1 So we can write: , A : B : C = 4 : 3 : 1 The ratio of the number deer to elephants to buffalo is 6 : 1 : 4 So we can write: D : E : B = 6 : 1 : 4 Notice that both ratios have a B in common. In order to COMBINE the two ...”
August 8, 2018
Brent@GMATPrepNow posted a reply to There is at least one red bal and at least one blue ball in in the Data Sufficiency forum
“Statement 1 indirectly tells us that it''s IMPOSSIBLE to select 2 blue balls. So, the box must contain fewer than 2 blue balls. Since we''re told that the box contains AT LEAST 1 blue ball, we can be certain that there is EXACTLY 1 blue ball. As far a red balls are concerned, all we know for ...”
August 7, 2018
Brent@GMATPrepNow posted a reply to If the speed of X meters per second is equivalent to the in the Problem Solving forum
“We want to convert meters per second to kilometers per hour First, since 1 kilometer = 1000 meters, we can also say that 1 kilometer/1000 meters = 1 Second, since 3600 seconds = 1 hour, we can also say that 3600 seconds/1 hour = 1 This means that multiplying a value by 1 kilometer/1000 meters ...”
August 7, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 A prominent investor who holds in the Critical Reasoning forum
“For boldfaced questions, students must be sure to generically summarize the roles that each part plays BEFORE examining the answer choices. Otherwise, it is much more difficult to determine the correct answer. So here''s my generic summary: The first boldfaced part describes the TYPICAL cause ...”
August 7, 2018
Brent@GMATPrepNow posted a reply to Is Hector taller than Charley? in the Data Sufficiency forum
“Target question: Is Hector taller than Charley? Statement 1: Hector is 5 feet 7 inches tall. No information about Charley. Charley COULD be 8 feet tall (i.e., taller than Hector) or Charley COULD be 3 feet tall (i.e., shorter than Hector) Since we cannot answer the target question with ...”
August 7, 2018
Brent@GMATPrepNow posted a reply to In the right triangle shown above, what is the value of a? in the Data Sufficiency forum
“Target question: What is the value of a? Let''s jump straight too.... Statements 1 and 2 combined Statement 1 tells us that c = 5. Statement 2 tells us that a < b There are several values of a, b and c that satisfy BOTH statements. Here are two cases: Case a: a = 3, b = 4 and c = 5. ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to In the right triangle shown above, what is the value of a? in the Data Sufficiency forum
“You''re assuming that a and b are INTEGERS. If that were the case, then C could be the correct answer.”
August 6, 2018
Brent@GMATPrepNow posted a reply to If the operation # is one of the four arithmetic operations- in the Data Sufficiency forum
“Target question: Is (6#2)#4 = 6#(2#4)? This is a good candidate for rephrasing the target question. Under what circumstances does (6#2)#4 = 6#(2#4) ? Let''s test each possible operation: ADDITION: If # represents addition, we get: (6+2)+4 = 6+(2+4) Simplify to get: 12 = 12. WORKS! So, ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 A company has developed a new in the Critical Reasoning forum
“You might want to revisit your solution here. The official answer is B Cheers, Brent”
August 6, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 A company has developed a new in the Critical Reasoning forum
“PREMISE: New sensor detects signals from beating heart PREMISE: Signals pass through almost everything CONCLUSION: New sensor will help locate trapped people quickly Now let''s examine each answer choice while reminding ourselves of the conclusion. A) Does this strengthen the conclusion ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to A data set with a mean of 60 has a standard deviation of 3.5 in the Problem Solving forum
“-----------ASIDE----------------------- A little extra background on standard deviations above and below the mean If, for example, a set has a standard deviation of 4, then: 1 standard deviation = 4 2 standard deviations = 8 3 standard deviations = 12 1.5 standard deviations = 6 0.25 ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to A data set with a mean of 60 has a standard deviation of 3.5 in the Problem Solving forum
“-----------ASIDE----------------------- A little extra background on standard deviations above and below the mean If, for example, a set has a standard deviation of 4, then: 1 standard deviation = 4 2 standard deviations = 8 3 standard deviations = 12 1.5 standard deviations = 6 0.25 ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to If integer k is equal to the sum of all even multiples of 15 in the Problem Solving forum
“Multiples of 15: 15, 30, 45, 60, 75, 90, 105, etc EVEN multiples of 15: 30, 60, 90, 120, .... So k = 300 + 330 + 360 + ... + 570 + 600 300 = 30(10) 330 = 30(11) 360 = 30(12) 390 = 30(13) . . . 570 = 30(19) 600 = 30(20) So k = 30(10 + 11 + 12 + ... + 19 + 20) ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to If x and y are consecutive odd integers such that x < y, in the Data Sufficiency forum
“Target question: What is the value of y + x? Given: x and y are consecutive odd integers such that x < y Statement 1: The product of xy is negative In order for the product xy to be NEGATIVE, it must be the case that one value is POSITIVE and one value of NEGATIVE. Since x and y are ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum
“Phew! I thought I was going bananas! Obviously not an actual GMATPrep question (as the OP suggests). I wonder what the original answer choice E was. I searched for this post elsewhere, and it appears to have been transcribed like that each time. Cheers, Brent”
August 6, 2018
Brent@GMATPrepNow posted a reply to Each of the 45 boxes on shelf J weighs less than each of the in the Data Sufficiency forum
“Target question: What is the median weight of 89 boxes on these shelves? Given: Each of the 45 boxes on shelf J weighs less than each of the 44 boxes on the shelf K. Let J1 be the weight of the lightest box on shelf J. Let J2 be the weight of the 2nd lightest box on shelf J. . . . Let ...”
August 6, 2018
beatthegmat posted a new topic called MBA Admissions: Tips for International Students in the The Application Process forum
“A large number of MBA students across the globe intend to pursue their degree outside their home country. Are you thinking of studying abroad? The United States, Europe and Canada are home to many of the world’s top-ranked business schools. Consider these tips if you’re hoping to make one of ...”
August 6, 2018
Brent@GMATPrepNow posted a reply to What is the value of integer z? in the Data Sufficiency forum
“Target question: What is the value of integer z? Statement 1: z represents the remainder when positive integer x is divided by positive integer (x – 1) In almost all cases, we will get a remainder of 1 when we divide x by (x-1). For example, 6 divided by 5 equals 1 with remainder 1 (in ...”
August 5, 2018
Brent@GMATPrepNow posted a new topic called Extra practice with ratios: A certain zoo has exactly five in the Problem Solving forum
“A certain zoo has exactly five types of animals: alligators, buffalo, camels, deer and elephants. The ratio of the number of alligators to buffalo to camels is 4 : 3 : 1. The ratio of the number deer to elephants to buffalo is 6 : 1 : 4. Which of the following could represent the total animal ...”
August 5, 2018
Brent@GMATPrepNow posted a reply to What is the remainder when n is divided by 26, given that in the Data Sufficiency forum
“Target question: What is the remainder when n is divided by 26 Given: n divided by 13 gives “a” as the quotient and “b” as the remainder? (a, b and n are positive integers) There''s a nice rule that say, "If N divided by D equals Q with remainder R, then N = DQ + R" For ...”
August 5, 2018
Brent@GMATPrepNow posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum
“Am I going crazy? I was also going to solve this question using the process of elimination. That is, if an answer choice CAN be the least common multiple (LCM) of x and y, then we''ll ELIMINATE that answer choice. (A) If x = 1 and y = 1, then the LCM is 1. Since xy = (1)(1) = 1, we can see ...”
August 5, 2018
Brent@GMATPrepNow posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum
“Key Concept: the least common multiple (LCM) of x and y is a multiple of x and a multiple of y. Let''s examine a few multiples: Multiples of 7: 7, 14, 21, 28, 35,... Multiples of 10: 10, 20, 30, 40, 50, 60, ,... Multiples of 3: 3, 6, 9, 12, 15, 18,,... Notice that the multiples of N are ...”
August 5, 2018
Brent@GMATPrepNow posted a reply to A contractor combined x tons of a gravel mixture that in the Data Sufficiency forum
“Let''s use some weighted averages to solve this question Weighted average of groups combined = (group A proportion)(group A average) + (group B proportion)(group B average) + (group C proportion)(group C average) + ... Target question: What is the value of x ? Given: A contractor combined x ...”
August 4, 2018
Brent@GMATPrepNow posted a reply to A certain movie star's salary for each film she makes consis in the Problem Solving forum
“Let F = the fixed amount the star receives for a movie Let p = the percentage of the gross revenue the star receives for a movie The star made $32 million on a film that grossed$100 million So, we can write: F + (p/100)(100) = 32 The star made $24 million on a film that grossed$60 ...”
August 4, 2018
Brent@GMATPrepNow posted a reply to If a and b represent positive single digits in the correctly in the Problem Solving forum
“Units digits first.... 2 + 3 + b yields a sum with units digit 0 So, b = 5 So, the top number and bottom number are now 22 and 45 We have: 22 a3 +45 ___ 90 22 + 45 = 67 So, we have: 67 + a3 = 90 Subtract 67 from both sides to get: a3 = 23 So, a = 2 What is the value of the two ...”
August 4, 2018
Brent@GMATPrepNow posted a reply to A certain junior class has 1,000 students and a certain in the Problem Solving forum
“P(selecting a sibling pair) = P(select a junior with a sibling AND select the senior who is that junior''s sibling) = P(select a junior with a sibling) x P(select the senior who is that junior''s siblingx 1/800 = 60/800,000 = 3/40,000 = A Note: P(select a junior with a sibling) = 60/1000, ...”
August 4, 2018
Brent@GMATPrepNow posted a reply to What is the hundredths digit of th decimal Z? in the Data Sufficiency forum
“Target question: What is the hundredths digit of the decimal z? Statement 1: The tenths digit of 100z is 2 Notice what happens when we take a decimal like 0.123456 and multiply it by 100. We get 12.345 (the tenths digit is 3) In the original decimal, the 3 was in the thousandths place. ...”
August 3, 2018
Brent@GMATPrepNow posted a reply to When a positive integer n is divided by 3, what is the remai in the Data Sufficiency forum
“Target question: What is the remainder when positive integer n is divided by 3? Statement 1: When n is divided by 5, the remainder is 2 -----ASIDE--------------------------------------- When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then ...”
August 3, 2018
Brent@GMATPrepNow posted a reply to If x^2+y^2=2xy, then (x-y)^2=? in the Problem Solving forum
“APPROACH #2 - Plug in numbers First find values of x and y that satisfy the given information (x² + y² = 2xy) Notice that, when x = 1 and y = 1, the equation, x² + y² = 2xy, holds true. We want to find the value of (x - y)² Plug in x = 1 and y = 1 to get: (x - y)² = (1 - 1)² = 0² = ...”
August 3, 2018
Brent@GMATPrepNow posted a reply to If x^2+y^2=2xy, then (x-y)^2=? in the Problem Solving forum
“APPROACH #1: Algebra Given: x² + y² = 2xy Subtract 2xy from both sides: x² - 2xy + y² = 0 (this should look familiar....it''s a special product) Factor left side: (x - y)(x - y) = 0 In other words, (x - y)² = 0 Answer: C Cheers, Brent”
August 3, 2018
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August 3, 2018
Brent@GMATPrepNow posted a reply to Is the integer x a multiple of 10? in the Data Sufficiency forum
“Yes, -10 and 0 are multiples of 10. We say that N is a multiple of d if we can write N = kd, where k is an integer. So, for example, 24 is a multiple of 8 because we can write 24 = (3)(8), and 3 is an integer. Likewise, -10 is a multiple of 10 because we can write -10 = (-1)(10), and -1 is an ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to Jessica can text 85 words per minute, while Maurice can text in the Problem Solving forum
“Since the answer choices are somewhat spread apart, we can probably use some estimation... Jessica can text 85 words per minute, while Maurice can text 10 words per minute So, COMBINED, they can text 95 words per minute Let''s round this up to 100 words per minute So, the number of words PER ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to A box of balls originally contained 2 blue balls for every in the Problem Solving forum
“We can also solve by using 2 variables... Let R = the ORIGINAL number of red balls in the box Let B = the ORIGINAL number of blue balls in the box A box of balls originally contained 2 blue balls for every red ball. In other words, the ratio of red balls to blue balls is 1/2 (aka 1 : 2) ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to Is 0 between x and y? in the Data Sufficiency forum
“Target question: Is 0 between x and y? Statement 1: x - y > 0 This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 2 and y = -1. In this case, the answer to the target question is YES, ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to If n = (x^5)*(y^7), where x and y are positive integers in the Data Sufficiency forum
“Statement 1 tells us that x and y are primes, but it doesn''t tell us that x and y are DIFFERENT primes. So, for example, if x = y = 2, then n = (2^5)(2^7) = 2^12, and 2^12 has 13 positive divisors. Conversely, if x = 2 and y = 3, then n = (2^5)(3^7), which has 48 positive divisors. So, ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to if product X costs 15000 and product Y costs 27000 in the Problem Solving forum
“Are you sure you transcribed the question correctly? As it stands, it''s not answerable. Cheers, Brent”
August 2, 2018
Brent@GMATPrepNow posted a reply to If (n+2)!/n!=90, then n=? in the Problem Solving forum
“(n+2)! = (n+2)(n+1)(n)(n-1)(n-2)....(3)(2)(1) n! = (n)(n-1)(n-2)....(3)(2)(1) Given: (n+2)!/n! = 90 Rewrite as: (n+2)(n+1)(n)(n-1)(n-2)....(3)(2)(1)/(n)(n-1)(n-2)....(3)(2)(1) = 90 Simplify: (n+2)(n+1) = 90 At this point, we can simply test the answer choices. A) n = 8 Take (n+2)(n+1) = ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to If x + 2 = (x + 11)/(x + 3) then x^2 + 4x - 5 = in the Problem Solving forum
“Given: x + 2 = (x + 11)/(x + 3) Multiply both sides by (x+3) to get: (x + 2)(x + 3) = (x + 11) Expand and simplify: x² + 5x + 6 = x + 11 Subtract x from both sides to get: x² + 4x + 6 = 11 Subtract 11 from both sides to get: x² + 4x - 5 = 0 Answer: C Cheers, Brent”
August 2, 2018
Brent@GMATPrepNow posted a reply to If 3 years ago Jennifer was 22 years old, how old is Carmen in the Data Sufficiency forum
“Target question: How old is Carmen now? Given: 3 years ago Jennifer was 22 years old So, Jennifer''s PRESENT age is 25 Statement 1: 10 years ago, Carmen was twice as old as Jennifer. If Jennifer''s PRESENT age is 25, then Jennifer''s age 10 YEARS AGO was 15 This means Carmen''s age 10 ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to A rope 40 feet long is cut into two pieces. If one piece is in the Problem Solving forum
“We can also test the answer choices Start with the middle answer choice C C) 18 If the shorter piece is 18 feet long, then the longer piece is 36 feet long Sum of lengths = 18 + 36 = 54 NO GOOD. We want a sum of 40 feet (as per the question) So, we can ELIMINATE C. Also, since we need ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to numbers in the Data Sufficiency forum
“ Given: x = y/7 Target question: Is x < 30? This is a good candidate for rephrasing the target question. Since x = y/7, we can replace x with y/7 to get... REPHRASED target question: Is y/7 < 30? Let''s rephrase the target question even more.... Take: y/7 < 30 Multiply both ...”
August 2, 2018
Brent@GMATPrepNow posted a reply to Challenge question: In the x-y coordinate plane, lines J in the Problem Solving forum
“Key Concepts: point B lies on line K, and point C lies on line K Since both points lie on line K, the slope between points B and C will be the same as the slope of line K. To find the slope of line K, let''s take the equation of line K (6y + 3x = -2), and rewrite it in slope y-intercept form (y ...”
August 1, 2018
Brent@GMATPrepNow posted a new topic called Challenge question: In the x-y coordinate plane, lines J in the Problem Solving forum
“Line J: 4x - 7 = 6y Line K: 6y + 3x = -2 Line L: 2x = 5 - y In the x-y coordinate plane, lines J, K and L are defined by the above equations. Point B is the point of intersection of lines J and K. Point C is the point of intersection of lines K and L. What is the slope of line segment BC? ...”
July 30, 2018
Brent@GMATPrepNow posted a reply to GMATPrep Practice Exam #1 - What Does my Percentile Mean? in the GMAT Math forum
“A 28-point percentile increase is no small matter. Day 42 is the last day that you learn new content, and the remaining days are devoted to taking practice tests and working on weaknesses. So, you can work on further improving your quant score during that time. Cheers, Brent”
July 29, 2018
beatthegmat posted a reply to GMAT OG 2019 Because many of Australia’s marsupials, in the Sentence Correction forum
“Entered OA has been corrected to E”
July 27, 2018
Brent@GMATPrepNow posted a reply to Challenge question: Which of the following is NOT a root... in the Problem Solving forum
“APPROACH 1: Plug in each answer choice to see which value does NOT satisfy the equation (slow but...) For example, C) x = 3 We get: (3² + 3 - 20)² - 2(3² + 3 - 20) - 63 = 17 Evaluate: (-8)² - 2(-8) - 63 = 17 Simplify: 64 - 16 - 63 = 17 Works! So, x = 3 is a valid solution Try D) x = 4 ...”
July 27, 2018
Brent@GMATPrepNow posted a reply to Is x a positive number? in the Data Sufficiency forum
“Target question: Is x a positive number? Statement 1: (x – 2)^2 > 2 Let''s TEST some values. There are several values of x that satisfy statement 1. Here are two: Case a: x = 4 works, since (4 – 2)^2 > 2. In this case, the answer to the target question is YES, x is positive Case ...”
July 27, 2018
Brent@GMATPrepNow posted a reply to Pears in the Data Sufficiency forum
“ Given: Pat bought 5 pounds of apples. Target question: How many pounds of pears could Pat have bought for the same amount of money? This is a good candidate for rephrasing the target question. Let A = the price per pound of apples Let P = the price per pound of pears If Pat bought 5 ...”
July 26, 2018
Brent@GMATPrepNow posted a reply to Challenge Question: the two lines are tangent to the circle in the Problem Solving forum
“If AC = 10, then BC = 10 https://i.imgur.com/43RWU7u.png Since ABC is an isosceles triangle, the following gray line will create two right triangles... https://i.imgur.com/VqAmtBP.png Now focus on the following blue triangle. Its measurements have a lot in common with the BASE 30-60-90 ...”
July 26, 2018
Brent@GMATPrepNow posted a reply to What is the remainder when 7^8 is divided by 100? in the Problem Solving forum
“Let''s examine 7^8 - 1 Why would I do this? Well, I know that 7^2 + 1 = 50, which is a factor of 100. So, perhaps it''s the case that 7^8 - 1 is divisible by 100, in which case 7^8 will leave a remainder of 1 when divided by 100 7^8 - 1 is a difference of squares. So, 7^8 - 1 = (7^4 + ...”
July 26, 2018
beatthegmat started following dnhgmat77
July 26, 2018
Brent@GMATPrepNow posted a reply to If a solid metal cylinder with radius 3 and height 12 is mel in the Problem Solving forum
“Key concept: the volume of the cylinder = the volume of the sphere volume of the cylinder = πr²h = π(3²)(12) = 108π So, the volume of the sphere = 108π Volume of sphere = (4/3)(π)(radius³) So, (4/3)(π)(radius³) = 108π Divide both sides by π to get: (4/3)(radius³) = 108 ...”
July 25, 2018
Brent@GMATPrepNow posted a new topic called Challenge question: Which of the following is NOT a root... in the Problem Solving forum
“Which of the following is NOT a root of the equation (x² + x - 20)² - 2(x² + x - 20) - 63 = 17 A) -6 B) -4 C) 3 D) 4 E) 5 Answer: D Difficulty level: 600 – 650 Source: www.gmatprepnow.com *Note: there are at least 3 different solutions possible”
July 25, 2018
Brent@GMATPrepNow posted a reply to If x and y are greater than 0, is x = 1 ? in the Data Sufficiency forum
“Target question: Is x = 1 ? Given: x and y are POSITIVE Statement 1: x/y = 1 Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = 1. In this case, the answer to the target question is YES, x DOES equal 1 Case b: ...”
July 25, 2018
Brent@GMATPrepNow posted a reply to 60 Day Study Guide: Missing Days in the The 60-Day GMAT Study Guide forum
“Sorry, but BTG won''t do that. Cheers, Brent”
July 25, 2018
Brent@GMATPrepNow posted a reply to A bus trip of 450 miles would have taken 1 hour less if the in the Problem Solving forum
“Let''s start with a word equation: travel time at actual speed = travel time at faster speed + 1 hour In other words: travel time at S mph = travel time at (S + 5) mph + 1 hour travel time = distance/speed So, we get: 450/S= 450/(S + 5) + 1 Multiply both sides by S to get: 450 = 450S/(S+5) + ...”
July 25, 2018
Brent@GMATPrepNow posted a reply to Moe is 20% taller than Jane. If Moe is x inches tall, which in the Problem Solving forum
“I created this question to highlight a common misconception that goes something like this: If Moe is 20% taller then Jane, then Jane must be 20% shorter than Moe. If you have this misconception, then you will incorrectly choose A as your answer. For more on this common misconception, read ...”
July 24, 2018
Brent@GMATPrepNow posted a reply to OG Quant Review - PS - Q 103 in the Problem Solving forum
“Given: x³ - x = (x - a)(x - b)(x - c) Factor x from left side: x(x² - 1) = (x - a)(x - b)(x - c) x² - 1 is a difference of squares, so we can factor that: x(x + 1)(x - 1) = (x - a)(x - b)(x - c) Rewrite first 2 terms as: (x - 0)(x - -1)(x - 1) = (x - a)(x - b)(x - c) Rearrange as: (x - 1)(x - ...”
July 24, 2018
Brent@GMATPrepNow posted a new topic called Challenge Question: the two lines are tangent to the circle in the Problem Solving forum
“https://i.imgur.com/c9biFrc.png The two lines are tangent to the circle. If AC = 10 and AB = 10√3, what is the area of the circle? A) 100π B) 150π C) 200π D) 250π E) 300π Answer: E Difficulty level: 650 - 700 Source: www.gmatprepnow.com *I''ll post a solution in 2 days”
July 24, 2018
beatthegmat started following nychivas
July 24, 2018
Brent@GMATPrepNow posted a new topic called If a solid metal cylinder with radius 3 and height 12 is mel in the Problem Solving forum
“If a solid metal cylinder with radius 3 and height 12 is melted and then formed into a solid sphere, what is the radius of the sphere? Note: Volume of sphere = (4/3)(π)(radius³) A) ∛6 B) ∛12 C) ∛36 D) 3 E) 3∛3 Answer: E Difficulty level: 600 - 650 Source: www.gmatprepnow.com ...”
July 23, 2018
Brent@GMATPrepNow posted a reply to Is 1/x>1/y? in the Data Sufficiency forum
“Target question: Is 1/x > 1/y? This is a good candidate for rephrasing the target question. Take: 1/x > 1/y Subtract 1/y from both sides to get: 1/x - 1/y > 0 Rewrite with common denominators: y/xy - x/xy > 0 Combine: (y - x)/xy > 0 REPHRASED target question: Is (y - ...”
July 23, 2018
Brent@GMATPrepNow posted a reply to If john makes a contribution to a charity fund at school in the Problem Solving forum
“Mitch''s approach is the most straightforward. However, here''s an algebraic version: Let J = the John''s donation Let a, b, c, d and e = the donations of the other 5 donors. John makes a contribution to a charity fund at school, the average contribution size will increase by 50% reaching $75 ...” July 23, 2018 Brent@GMATPrepNow posted a new topic called Moe is 20% taller than Jane. If Moe is x inches tall, which in the Problem Solving forum “Moe is 20% taller than Jane. If Moe is x inches tall, which of the following represents Jane''s height in inches? A) 4x/5 B) 5x/6 C) 2x/3 D) 5x/4 E) 6x/5 Answer: B Difficulty level: 550 - 600 Source: www.gmatprepnow.com *I''ll post a solution in 2 days” July 22, 2018 Brent@GMATPrepNow posted a reply to If there are fewer than 8 zeroes in the Problem Solving forum “First: (t/1000)^4 = (t^4)/(1000^4) Now recognize that 1000^4 = (10^3)^4 = 10^12 So, (t/1000)^4 = (t^4)/(1000^4) = (t^4)/(10^12) IMPORTANT: When we divide a number by 10^12, we must move the decimal point 12 spaces to the left So, for example, 1234567/10^12 = 0.000001234567 Likewise, ...” July 22, 2018 Brent@GMATPrepNow posted a reply to At least 100 students at a certain high school study in the Data Sufficiency forum “We can use the Double Matrix method. It can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of students, and the two characteristics are: - studies Japanese or does NOT ...” July 20, 2018 beatthegmat started following belle82edith July 20, 2018 beatthegmat started following BrentCarpenetti July 20, 2018 beatthegmat started following gdavis2000 July 20, 2018 July 20, 2018 beatthegmat started following AYD34 July 20, 2018 beatthegmat started following Masomo July 20, 2018 beatthegmat started following mir.yahya July 20, 2018 beatthegmat started following jnellaz July 20, 2018 beatthegmat started following aim-wsc July 20, 2018 Brent@GMATPrepNow posted a reply to If 75 percent of the guests at a certain banquet ordered in the Data Sufficiency forum “Another approach for this question is to use the Double Matrix method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it. Here, we have a population of guests, and the two characteristics are: - ordered dessert or ...” July 19, 2018 beatthegmat started following Leninmiguel July 18, 2018 beatthegmat started following Mr. B School July 18, 2018 beatthegmat started following ReachingHigher July 18, 2018 beatthegmat started following BJW34 July 18, 2018 Brent@GMATPrepNow posted a reply to The product of 4 consecutive odd integers is negative. What in the Data Sufficiency forum “Target question: What is the largest odd integer? Given: The product of 4 consecutive odd integers is negative. It''s worth taking the time to analyze what this is telling us. If the product of 4 consecutive odd integers is negative, then there are only 2 possible scenarios: Scenario #1: ...” July 17, 2018 Brent@GMATPrepNow posted a reply to Is x<0? in the GMAT Math forum “Target question: Is x<0? Key Concept: ODD exponents preserve the sign of the base. In other words, POSITIVE^ODD = POSITIVE and NEGATIVE^ODD = NEGATIVE Statement 1: x^5 < 0 This is telling us that x^5 = NEGATIVE So, it must be the case that x is NEGATIVE So, the answer to the ...” July 17, 2018 Brent@GMATPrepNow posted a reply to In the xy-plane, points A, B and C are not on the same line in the Data Sufficiency forum “Target question: Is the slope of line BC negative? We can quickly see that statements 1 and 2 (alone) are NOT SUFFICIENT. This brings us to... Statements 1 and 2 combined If we draw the line segment AB with slope -1, then we get something like this: ...” July 17, 2018 Brent@GMATPrepNow posted a reply to If x < 12, then it must be true that in the Problem Solving forum “NOTE: this is one of those questions that require us to check/test each answer choice. In these situations, always check the answer choices from E to A, because the correct answer is typically closer to the bottom than to the top. For more on this strategy, see my article: ...” July 17, 2018 Brent@GMATPrepNow posted a reply to If 8x=2^y what is the value of x, in terms of y? in the Problem Solving forum “Another approach is to find some values of x and y that satisfy the given equation 8x = 2^y One solution that works is x = 1 and y = 3, since 8(1) = 2^3 Now take each answer choice and replace x and y with 1 and 3 respectively and see which one yields a true equation: A. 1 = 2^[3(3) - 2] ...” July 17, 2018 Brent@GMATPrepNow posted a reply to Challenge: If line k passes through the points (48, 33) and in the Problem Solving forum “If we sketch the two given points, we can quickly see that the slope (aka rise/run) of the line = 11/17 https://i.imgur.com/jJtP4PZ.png So, we can use this information to plot another point on the line... https://i.imgur.com/pfA3jL1.png And another point... ...” July 11, 2018 Brent@GMATPrepNow posted a reply to Challenge question: If ABCD is a square, and XYZ in the Problem Solving forum “If ∆XYZ is EQUILATERAL, then each angle is 60° So, if we draw a line from the center to a vertex, we''ll get two 30° angles.... https://i.imgur.com/4s2wG5R.png Now drop a line down like this to create a SPECIAL 30-60-90 right triangle https://i.imgur.com/aLVDzG4.png Since the base ...” July 10, 2018 Brent@GMATPrepNow posted a new topic called Challenge: If line k passes through the points (48, 33) and in the Problem Solving forum “If line k passes through the points (48, 33) and (31, 22), what is the x-intercept of line k? A) -25 10/11 B) -3 C) -1 16/17 D) 1 16/17 E) 25 10/11 Answer: B Difficulty level: 600 – 650 Source: www.gmatprepnow.com *I''ll post a solution in 2 days” July 9, 2018 Brent@GMATPrepNow posted a reply to What is the area of the shaded region, if the area of the in the Problem Solving forum “EXTRA PRACTICE Here are two more questions involving an equilateral triangle inscribed in a circle: - http://www.beatthegmat.com/triangle-inside-a-circle-t90961.html - http://www.beatthegmat.com/if-a-smaller-circle-is-inscribed-in-an-equilateral-triangle-t289365.html Cheers, Brent” July 9, 2018 Brent@GMATPrepNow posted a reply to Jalal weighs twicw as much as Meena. Meena's weight is 60% in the Problem Solving forum “An alternative approach is to assign weights that meet the given conditions. Meena''s weight is 60% of Bahar''s weight Let''s let Bahar''s weight = 100 kg So, Meena''s weight = 60 kg Jalal weighs twice as much as Meena. Since Meena weight 60 kg (see above) then Jalal''s weight = 120 kg ...” July 8, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: If ABCD is a square, and XYZ in the Problem Solving forum “https://i.imgur.com/sd4EcIB.png If ABCD is a square, and XYZ is an equilateral triangle, then the area of the square is how many times the area of the triangle? A) (4√3)/3 B) (8√3)/3 C) 2√6 D) (16√3)/9 E) (16√2)/3 Answer: D Difficulty level: 650 – 700 Source: ...” July 8, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 If S = 1 + in the Problem Solving forum “So, S = 1 + 1/4 + 1/9 + 1/16 + 1/25 + 1/36 + . . . . Now, let''s convert a few of the fractions to decimal approximations... S = 1 + 0.25 + 0.11 + 0.06 + 0.04 + . . . Add the first 4 values.... S = 1.42 + 0.04 + . . . IMPORTANT: Notice that each fraction is less than the fraction ...” July 8, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 In the xy-coordinate plane in the Problem Solving forum “KEY CONCEPT: In order for a point to be ON a line, the x- and y-coordinates of the point must satisfy the equation of that line So, for example, the point (3,7) lies ON the line defined by the equation y = 2x + 1, because x = 3 and y = 7 satisfy the equation y = 2x + 1 That is, 7 = 2(3) + 1 ...” July 7, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Greg assembles units of a certain in the Problem Solving forum “GIVEN: Total pay for 2 days is$180 In order to MAXIMIZE the number of units assembled on one of the days, we must MINIMIZE the number of units assembled on the other day We''re told that Greg assembled at least 30 units each day. So, the MINIMUM is 30 units Let''s say that Greg assembled 30 ...”
July 7, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Which of the following is closest in the Problem Solving forum
“ALWAYS check the answer choices before solving the question! When we do so, we see that the answer choices are VERY spread apart, which means we can save a ton of time by being super aggressive with our approximations (aka rounding) So, we get: √[(4.2)(1590)/15.7 ≈ √[(4)(1600)/16] ≈ ...”
July 6, 2018
Brent@GMATPrepNow posted a reply to Challenge question: In the above figure, the small circle... in the Problem Solving forum
“If we recognize that the hypotenuse of the blue right triangle below is twice the length of one side, we can see that this is a 30-60-90 SPECIAL TRIANGLE https://i.imgur.com/qxIw8NQ.png In the base triangle (on the right), the side opposite the 30° has length 1. So, the magnification factor of ...”
July 5, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 In the figure shown in the Problem Solving forum
“Since angles on a line must add to 180°, we can see that there are three 30° angles in our diagram... https://i.imgur.com/V6wFovz.png Next, let''s focus on the BLUE triangle. https://i.imgur.com/cdsQPY8.png Since angles in a triangle must add to 180° (and since we already have two angles ...”
July 4, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 10, 4, 26, 16 in the Problem Solving forum
“Arrange the 4 values in ascending order: {4, 10, 16, 26} Since we have an EVEN number of values, the median will be the average of the 2 middlemost values. So, the median = (10 + 16)2 = 26/2 = 13 Answer: B Cheers, Brent”
July 4, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Over the past 7 weeks in the Problem Solving forum
“Average = ($74 +$69 + $64 +$79 + $64 +$84 + $77)/7 =$511/7 = $73 Answer: C Cheers, Brent” July 4, 2018 Brent@GMATPrepNow posted a reply to When the positive integer x is divided by 11 in the Problem Solving forum “A fast approach is to find a value of x that meets the given conditions. When the positive integer x is divided by 11, the quotient is y and the remainder 3. When x is divided by 19, the remainder is also 3.... Notice that x = 3 meets the above conditions. 3 divided by 11 = 0 with remainder ...” July 4, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 The value of the above in the Problem Solving forum “One option is to replace each fraction in the NUMERATOR with its decimal approximation. 7/8 ≈ 0.88 1/9 ≈ 0.11 1/2 = 0.5 So, (7/8 + 1/9)/(1/2) ≈ (0.88 + 0.11)/(1/2) ≈ (0.99)/(1/2) ≈ 1/(1/2) ≈ 2 Answer: A Cheers, Brent” July 4, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 If a + b + c = 12 in the Data Sufficiency forum “Target question: What is the value of b ? Given: a + b + c = 12 Statement 1: a + b = 8 We can take a + b + c = 12 and rewrite it as (a + b) + c = 12 Now replace a+b with 8 to get: (8) + c = 12 Solve: c = 4 Now that we know the value of c, can we find the value of b? No. Let''s ...” July 4, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 The table shows partial results in the Problem Solving forum “Since we aren''t told the number of people involved in the survey, let''s make things easier on ourselves and assign a "nice" value to the number of people involved in the survey. Let''s say there were 100 people in the survey. When we apply this to our table, we see that 35 people ...” July 4, 2018 Brent@GMATPrepNow posted a reply to Challenge question: If j and k are positive integers, and (k in the Problem Solving forum “Let''s focus on the value of j. Since j is an integer, it must be the case that j^6 equals some power of 6. So, for example, j^6 could equal 29^6. Likewise, j^6 could equal 29^12, because we can rewrite 29^12 as (29^2)^6 in which case, we can see that (29^2)^6 is a power of 6 Likewise, j^6 ...” July 3, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: In the above figure, the small circle... in the Problem Solving forum “https://i.imgur.com/XrqxGNd.png In the above figure, the small circle and big circle have diameters of 3 and 6 respectively. If AB||CD, and both circles share the same center, what is the area of the shaded region? A) 9/2 + 2π B) 9/2 + 3π C) 3√3 + 3π D) 6√3 + 2π E) (9/2)√3 + ...” July 3, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Ron is 4 inches taller than in the Problem Solving forum “Let A = Amy''s height So, A + 4 = Ron''s height And A + 5 = Barbara''s height If Barbara''s height = 65, then we can write: A + 5 = 65 Solve to get: A = 60 So, Amy''s height is 60, Ron''s height is 64 and Barbara''s height is 65 So, the median height = 64 Answer: E Cheers, Brent” July 3, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 While a family was away on in the Problem Solving forum “..... paid a neighborhood boy$11 per week to mow their lawn... So, in 3 weeks, the amount the family paid for lawn-moving = (3 weeks)($11/week) =$33 ...the family paid $4 per DAY to feed and walk their dog... 3 weeks = 21 DAYS So, the amount the family paid for dog care = (21 days)($4/day) = ...”
July 3, 2018
beatthegmat posted a new topic called The Smart Choice: Benefits of Taking the GRE® General Test in the GMAT Strategy forum
“Are you thinking of pursuing a professional business degree? More business school students than ever before are getting into top-ranked business programs using GRE<sup>®</sup> scores. You do have testing options. If you’re weighing which test is right for you, this overview of the ...”
July 2, 2018
Brent@GMATPrepNow posted a reply to What is the ratio of 2a to b? in the Data Sufficiency forum
“Target question: What is the ratio of 2a to b? In other words, What is the value of 2a/b? Statement 1: a/b = 2 Take: a/b = 2 Multiply both sides by 2 to get: 2a/b = 4 So, the answer to the target question is 2a/b = 4 Since we can answer the target question with certainty, statement 1 is ...”
July 2, 2018
Brent@GMATPrepNow posted a reply to A certain company employs 6 senior officers and 4 junior in the Problem Solving forum
“Take the task of creating the 4-person committee and break it into stages. Stage 1: Select 3 senior officers Since the order of the selected officers does not matter, we can use combinations. We can select 3 officers from 6 senior officers 6C3 ways (= 20 ways) Stage 2: Select 1 junior ...”
July 2, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 If the circumference of a in the Problem Solving forum
“We have the following: https://i.imgur.com/NccAGgy.png The perimeter of the circle = 25π We can see that the perimeter of the square is GREATER THAN the perimeter of the circle 25π ≈ (25)(3) ≈ 75 So, the perimeter of the square is GREATER THAN 25π Check the answer ...”
July 2, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 If the circumference of a in the Problem Solving forum
“We have the following: https://i.imgur.com/NccAGgy.png The perimeter of the circle = 25π We can see that the perimeter of the square is GREATER THAN the perimeter of the circle 25π ≈ (25)(3) ≈ 75 So, the perimeter of the square is GREATER THAN 25π Check the answer ...”
July 2, 2018
Brent@GMATPrepNow posted a new topic called Challenge question: If j and k are positive integers, and (k in the Problem Solving forum
“If j and k are positive integers, and (k)(j^6) = (29^29)(11^11), then how many possible values of k are there? A) 8 B) 10 C) 12 D) 15 E) 18 Answer: B Difficulty level: 650-700 Source: www.gmatprepnow.com *I''ll post a solution in 2 days”
July 1, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 In a recent town election in the Data Sufficiency forum
“Let F = the number of votes in FAVOR of the proposal Let A = the number of votes AGAINST the proposal Target question: What is the value of F/A? Statement 1: There were 60 more votes in favor of the proposal than against the proposal. In other words, F = A + 60 Let''s TEST some values. ...”
July 1, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Last year $48,000 of a in the Problem Solving forum “Although I believe it''s best to use one variable to solve this question, we can also use Let x = the amount (in dollars) that ONE employee received Let y = the amount (in dollars) that ONE owner received Each owner received 3 times as much as each employee So, we can write: y = 3x Last year ...” July 1, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Last year$48,000 of a in the Problem Solving forum
“Each owner received 3 times as much as each employee Let E = the amount (in dollars) that ONE employee received So, 3E = the amount (in dollars) that ONE owner received Last year $48,000 of a certain store''s profit was shared by its 2 owners and their 10 employees. In other words: 3E + 3E + ...” July 1, 2018 Brent@GMATPrepNow posted a reply to How old will Fred be in 3 years? in the Data Sufficiency forum “Let''s solve the question using 2 variables Let F = Fred''s PRESENT age Let G = Gary''s PRESENT age Target question: What is the value of F+3 ? Statement 1: Presently, Fred is 4 times as old as Gary. In other words, F = 4G There are several values of F and G that satisfy the equation F ...” June 30, 2018 Brent@GMATPrepNow posted a reply to If y is 4 greater than one-fourth of x, and in the Problem Solving forum “The solutions above demonstrate an algebraic approach. We can also solve the question using the INPUT-OUTPUT approach. Let''s find values for x and y that satisfy the given information (y is 4 greater than one-fourth of x) A nice pair of values is x = 4 and y = 5 When we use these values, ...” June 30, 2018 Brent@GMATPrepNow posted a reply to Tips for correcting careless mistakes in GMAT quant section in the GMAT Math forum “If silly mistakes are hurting your score, then it''s important that you identify and categorize these mistakes. Some examples might include: - sloppy writing causes a 7 to mysteriously turn into a 1 - you forget that a question is an EXCEPT question. - you fail to notice crucial information such ...” June 30, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Of the following, which is in the Problem Solving forum “1.03 is a little bit BIGGER than 1 4.86 is a little bit SMALLER than 5 So, (1.03)(4.86) will be CLOSE TO (1)(5), aka 5 So, 60.2/(1.03 x 4.86) ≈ 60/(1.03 x 4.86) ≈ 60/5 ≈ 12 Answer: B Cheers, Brent” June 30, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Robin invested a total of$12,000 in the Data Sufficiency forum
“Let X = The number of dollars invested in investment X Let Y = The number of dollars invested in investment Y Target question: What is the value of Y? Given: Robin invested a total of $12,000 in two investments, X and Y, so that the investments earned the same amount of simple annual ...” June 30, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Is the sum of the prices of the in the Data Sufficiency forum “Target question: Is the sum of the prices of the 3 books less than$48 ? Let A = price of the LEAST expensive book (in dollars) Let B = price of the mid-priced expensive book (in dollars) Let C = price of the MOST expensive book (in dollars) So, A < B < C Statement 1: The price of ...”
June 30, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 The figure above represents a in the Problem Solving forum
“Let''s add the radius of 6 feet to the diagram to get: https://i.imgur.com/JSxL60Q.png From here, we can see the right triangle hiding within the diagram, which means we can apply the Pythagorean Theorem. Se can write: h² + 2² = 6² Simplify: h² + 4 = 36 So, we get: h² = 32 This means ...”
June 30, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 Is in the Data Sufficiency forum
“Target question: Is (x+1)/(y+1) > x/y ? Statement 1: 0 < x < y This tells us that y is POSITIVE, which means y+1 is also POSITIVE. This means we can safely take the inequality (x+1)/(y+1) > x/y and safely multiply both sides by y When we do so, we get: (y)(x+1)/(y+1) > x ...”
June 30, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 During a trip that they in the Problem Solving forum
“Let x = the number of miles Rafael drove Average = 80 So, (72 + 78 + 83 + x)/4 = 80 Multiply both sides by 4 to get: 72 + 78 + 83 + x = 320 Simplify: 233 + x = 320 Solve: x = 87 Answer: D Cheers, Brent”
June 29, 2018
Brent@GMATPrepNow posted a reply to Algebra : Applied Problem in the Problem Solving forum
“Here''s a slightly different approach. It takes 8 hours to fill to 3/5 of its capacity. So, in 1/3 the time, we''ll fill 1/3 as much. In other words, in 8/3 hours we can fill 1/5 of the pool. We want to know how long it will take to fill 2/5 of the pool. So, it will take twice as long as ...”
June 29, 2018
Brent@GMATPrepNow posted a reply to Algebra : Applied Problem in the Problem Solving forum
“We know it takes 8 hours to fill to 3/5 of its capacity. We want to know how long it will take to fill the remaining 2/5 of capacity. IMPORTANT: 2/5 is 2/3 as big as 3/5 So, if it takes 8 hours to fill 3/5 of the pool, then the time to fill 2/5 of the pool = (2/3)(8) hours = 16/3 hours = 5 1/3 ...”
June 29, 2018
Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 A company bought 3 printers in the Data Sufficiency forum
“Let P = price of ONE printer Let S = price of ONE scanner Target question: What is the value of S? Statement 1: The total price of the (3) printers and the (1) scanner was $1,300. So, we can write: 3P + S = 1300 Does this provide enough information to determine the value of S? No. ...” June 29, 2018 Brent@GMATPrepNow posted a reply to GMAT Official Guide 2019 What is the circumference in the Data Sufficiency forum “Target question: What is the circumference of circle C ? Statement 1: The radius of circle C is 2π. Useful formula: circumference = (2π)(radius) Now that we know the radius is 2π, the circumference = 2π(2π) = 4π² In other words, the answer to the target question is the circumference ...” June 29, 2018 Brent@GMATPrepNow posted a reply to Allison and Barbara are part of an 8-member dance troupe. in the Problem Solving forum “Asking,"What fraction of all the possible ensembles that include Allison will also include Barbara?" is the same as asking, "What is the probability that Allison are Barbara are in the same troupe? Step 1: Place Allison in one of the troupes. Step 2: Choose the 3 remaining ...” June 27, 2018 Brent@GMATPrepNow posted a reply to If a certain vase contains in the Data Sufficiency forum “Here''s a solution that uses 2 variables Let R = number of roses in the vase Let T = number of tulips in the vase Target question: What is the value of T? Statement 1: The number of roses in the vase is 4 times the number of tulips in the vase. We can write: R = 4T As we can see, ...” June 27, 2018 Brent@GMATPrepNow posted a reply to Which of the following statements in the Problem Solving forum “There''s a nice rule that says, "In a set where the numbers are equally spaced, the mean will equal the median." For example, in each of the following sets, the mean and median are equal: {7, 9, 11, 13, 15} {-1, 4, 9, 14} {3, 4, 5, 6} Since consecutive integers are equally spaced, ...” June 27, 2018 Brent@GMATPrepNow posted a reply to In a certain fraction, the in the Problem Solving forum “Let N = the numerator Let D = the denominator ...the denominator is 16 greater than the numerator. We can write: D = N + 16 If the fraction is equivalent to 80 percent... We can write: N/D = 80/100 Simplify to get: N/D = 4/5 Cross multiply to get: 5N = 4D ...what is the denominator of ...” June 27, 2018 beatthegmat started following chia021 June 27, 2018 Brent@GMATPrepNow posted a reply to If x is negative and y is positive, which of the following in the Problem Solving forum “The key word here is MUST. So, we''re looking for an expression that must always be positive C. 2y + x If y = 10 and x = -1, then 2y + x = 2(10) + (-1) = 19. So, 2y + x CAN be positive. However, if y = 3 and x = -7, then 2y + x = 2(3) + (-7) = -1. So, 2y + x CAN be negative. Since we''re ...” June 26, 2018 Brent@GMATPrepNow posted a reply to If x is negative and y is positive, which of the following in the Problem Solving forum “NOTE: this is one of those questions that require us to check/test each answer choice. In these situations, always check the answer choices from E to A, because the correct answer is typically closer to the bottom than to the top. For more on this strategy, see my article: ...” June 26, 2018 Brent@GMATPrepNow posted a reply to In a sequence of 40 numbers, each term, except for the first in the Problem Solving forum “Notice that each term is 7 less than the term before it. This means the greatest term will be the first term In other words, term1 = 281 Let''s list a few terms of the sequence and look for a pattern: term1 = 281 term2 = 281 - 7 term3 = 281 - 7 - 7 = 218 - (2)(7) term4 = 281 - 7 - 7 - ...” June 26, 2018 Brent@GMATPrepNow posted a new topic called How old will Fred be in 3 years? in the Data Sufficiency forum “How old will Fred be in 3 years? (1) Presently, Fred is 4 times as old as Gary. (2) In 10 years, Fred will be 3 times as old as Gary. Answer: C Difficulty level: 550 - 600 Source: www.gmatprepnow.com” June 26, 2018 Brent@GMATPrepNow posted a reply to Challenge question: In a group of x students, w students are in the Problem Solving forum “Let''s apply the Double Matrix Method, a technique that can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of students, and the two characteristics are: - taking French ...” June 26, 2018 Brent@GMATPrepNow posted a new topic called If y is 4 greater than one-fourth of x, and in the Problem Solving forum “If y is 4 greater than one-fourth of x, and x ≠ 0, what is the ratio of y to x in terms of x? A) (x² + 16x)/4 B) (4x + 16)/x C) (x + 16)/4x D) (4x + 1)/x E) (x + 16)/x Answer: C Difficulty level: 550-600 Source: www.gmatprepnow.com *I''ll post a solution in 2 days” June 25, 2018 Brent@GMATPrepNow posted a reply to OG Mixtures Problem in the Problem Solving forum “This looks like a job for weighted averages! Weighted average of groups combined = (group A proportion)(group A average) + (group B proportion)(group B average) + (group C proportion)(group C average) + ... Mixture X is 40 percent ryegrass Mixture Y is 25 percent ryegrass Let x = the ...” June 25, 2018 Brent@GMATPrepNow posted a reply to gmat prep question in the Problem Solving forum “Here''s the complete question (with answer choices): Height of tree on day 0 = 4 Let d = the height increase each year Height of tree at the end of the 1st year = 4+d Height of tree at the end of the 2nd year = 4+d+d = 4 + 2d Height of tree at the end of the 3rd year = 4+d+d+d = 4 + 3d ...” June 25, 2018 Brent@GMATPrepNow posted a reply to Alice and Bob drive the same car. Alice drives the car for 1 in the Problem Solving forum “Let T = total distance traveled Alice drives the car for 1/4 of one trip, and Bob drives the car for the remainder of the same trip In other words, Bob drove 3/4 the distance. We can write: (1/4)T = distance Alice drove And (3/4)T = distance Bob drove The difference between the distance ...” June 25, 2018 Brent@GMATPrepNow posted a reply to Within a group of students, x students are taking English, y in the Problem Solving forum “We can solve this by using the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of students, and the two characteristics are: - ...” June 24, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: In a group of x students, w students are in the Problem Solving forum “In a group of x students, w students are taking Chemistry but not French, y students are taking French but not Chemistry, and z students are NOT taking French. Which of the following represents the number of students who are taking Chemistry? A) x - y - z - w B) x - y + z + w C) x - y - z + w ...” June 24, 2018 Brent@GMATPrepNow posted a reply to Challenge: How many positive integers less than 500 begin in the Problem Solving forum “Here''s a different approach: There are 499 integers from 1 to 499 inclusive. Let''s determine how many of those 499 integers DO NOT meet the condition of beginning with a 3, ending with a 3, or both 1-digit integers that DO NOT begin with a 3, end with a 3, or both 1, 2, 4, 5, 6, 7, 8, ...” June 22, 2018 Brent@GMATPrepNow posted a new topic called Within a group of students, x students are taking English, y in the Problem Solving forum “Within a group of students, x students are taking English, y students are taking Math, and z students are taking both English and Math. Which of the following represents the number of students who are taking English or Math but not both? A) x + y - z B) x + y + z C) 2x + 2y - z D) x + y - 2z ...” June 21, 2018 Brent@GMATPrepNow posted a reply to When a, b and c are consecutive positive even integers such in the Problem Solving forum “If a, b and c are consecutive EVEN integers, and a>b>c, then we we know that b is 2 greater than c, and a is 2 greater than b So, we can write: b = c + 2 a = c + 4 Now let''s check the answer choices from E to A -----ASIDE---------------- This is one of those questions that require ...” June 21, 2018 Brent@GMATPrepNow posted a reply to GMATPrep Exponent Problem in the Problem Solving forum “4^17 - 2^28 = (2²)^17 - 2^28 = 2^34 - 2^28 = 2^28(2^6 - 1) = 2^26(64- 1) = (2^26)(63) = (2^26)(3)(3)(7) So, the PRIME factors are 2, 3, and 7 Answer: D Cheers, Brent” June 21, 2018 Brent@GMATPrepNow posted a reply to Problem involving prime factors in the Problem Solving forum “Important Concept: If integer k is greater than 1, and k is a factor (divisor) of N, then k is not a divisor of N+1 For example, since 7 is a factor of 350, we know that 7 is not a factor of (350+1) Similarly, since 8 is a factor of 312, we know that 8 is not a factor of 313 Now let’s ...” June 21, 2018 Brent@GMATPrepNow posted a reply to Challenge question: N is a 2-digit integer. When the di in the Data Sufficiency forum “Target question: What is the value of N? Given: N is a 2-digit integer. When the digits of N are reversed, the resulting number is M. -1 < N – M < 15 Let x = the tens digit of N Let y = the units digit of N So, the VALUE of N = 10x + y When we reverse the digits, we get M = yx ...” June 20, 2018 Brent@GMATPrepNow posted a reply to If s is a positive integer, is s prime? in the Data Sufficiency forum “Target question: Is s prime? Given: s is a positive integer Statement 1: 21/s is an integer So, s can equal 1, 3, 7 or 21 If s = 1, the answer to the target question is NO, s is NOT prime If s = 3, the answer to the target question is YES, s IS prime Since we cannot answer the target ...” June 20, 2018 Brent@GMATPrepNow posted a reply to What is the maximum number of points of intersection of in the Problem Solving forum “With a quick sketch.... https://i.imgur.com/1knFxvl.png ....we can get 2 points of intersection. With the exception of a formal proof, we''re left on our own accord to find a situation with more than 2 points of intersection. If we can''t identify such a situation, we must go with C ...” June 20, 2018 Brent@GMATPrepNow posted a reply to Challenge question: Each edge of the above cube has length 1 in the Problem Solving forum “If we open up the cube, we get something like this.... https://i.imgur.com/9LRJhWQ.png Let x = the distance from A to B https://i.imgur.com/xuj615V.png Since we have a right triangle, we can apply the Pythagorean Theorem to get: 1² + 2² = x² Simplify to get: 1 + 4 = x² So, 5 = x², which ...” June 20, 2018 Brent@GMATPrepNow posted a reply to A house cost Ms. Jones C dollars in 1965. Three years in the Problem Solving forum “A house cost Ms. Jones C dollars in 1965. Three years later she sold the house for 25% more than she paid for it. So, 3 years later, the house sold for 1.25C dollars She has to pay a tax of 50% of the gain. (The gain is the selling price minus the cost.) How much tax must Ms. Jones pay? Gain = ...” June 20, 2018 Brent@GMATPrepNow posted a new topic called Challenge: How many positive integers less than 500 begin in the Problem Solving forum “How many positive integers less than 500 begin with a 3, end with a 3, or both? A) 149 B) 150 C) 159 D) 199 E) 200 Answer: A Difficulty level: 600 – 650 Source: www.gmatprepnow.com *I''ll post a full solution in 2 days” June 20, 2018 Brent@GMATPrepNow posted a reply to Challenge: Is AB || CD? in the Data Sufficiency forum “Target question: Is AB || CD? I''ll use the two shapes below (rectangle and isosceles trapezoid) show that the correct answer is E https://i.imgur.com/zRR75tm.png Statement 1: AC = BD Notice that rectangle and isosceles trapezoid both satisfy the condition that AC = BD ...” June 20, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: N is a 2-digit integer. When the di in the Data Sufficiency forum “N is a 2-digit integer. When the digits of N are reversed, the resulting number is M. If -1 < N – M < 15, what is the value of N? (1) The sum of N’s digits is 15. (2) The tens digit of N is 1 greater its units digit Answer: A Difficulty level: 650 - 700 Source: ...” June 19, 2018 Brent@GMATPrepNow posted a reply to Rate my AWA in the GMAT Essays (AWA) forum “My 2 cents: I like the idea of starting with a summary of the original argument, but your argument summary is only 2 words shorter than the original argument. Your last paragraph deviates from the primary goal of the essay (determine how well the conclusion follows from the premise). Instead, ...” June 18, 2018 Brent@GMATPrepNow posted a new topic called Challenge: Is AB || CD? in the Data Sufficiency forum “https://i.imgur.com/qNiBsQb.png Is AB || CD? (1) AC = BD (2) AB = CD Answer: E Difficulty level: 600 - 650 Source: www.gmatprepnow.com *I''ll post a full solution in 2 days” June 18, 2018 Brent@GMATPrepNow posted a reply to What is the volume of the largest cube that can in the Problem Solving forum “Let''s first inscribe the largest possible square inside the circle https://i.imgur.com/VYR1e8V.png Since the radius of the cylinder is 2, we know that the DIAMETER = 4 https://i.imgur.com/Gg3toPv.png Since we have a RIGHT TRIANGLE, we can apply the Pythagorean Theorem to get: x² + x² = ...” June 18, 2018 Brent@GMATPrepNow posted a reply to Help!! in the Data Sufficiency forum “A certain business printer can print 40 characters per second... 40 x 60 = 2400 So, the business printer can print 2400 characters PER MINUTE ..., which is 4 times as fast as an average printer. 2400/4 = 600 So, the average printer can print 600 characters PER MINUTE If an average printer ...” June 18, 2018 Brent@GMATPrepNow posted a reply to gmat prep in the Problem Solving forum “n= 1/3 + 1/3^2 + 1/3^3 = 1/3 + 1/9 + 1/27 = 9/27 + 3/27 + 1/27 = 13/27 ≈ 1/2 Answer: C Cheers, Brent” June 18, 2018 Brent@GMATPrepNow posted a reply to GMAT PREP QUES in the Problem Solving forum “-----ASIDE--------------------- A lot of integer property questions can be solved using prime factorization. For questions involving divisibility, divisors, factors and multiples, we can say: If N is divisible by k (i.e., N is a multiple of k), then k is "hiding" within the prime ...” June 18, 2018 Brent@GMATPrepNow posted a reply to gmat prep q in the Problem Solving forum June 18, 2018 Brent@GMATPrepNow posted a reply to gmat prep q in the Problem Solving forum “Here''s the full question... 2^(X+Y)²/ 2^(X-Y)² = 2^(X² + 2XY + Y²)/ 2^(X² - 2XY + Y²) = 2^(4XY) = 2^4 = 16 Answer: D Cheers, Brent” June 18, 2018 Brent@GMATPrepNow posted a reply to If x is a 3–digit number, is x even? in the Data Sufficiency forum “Target question: Is x even? Given: x is a 3–digit number, Jump to...... Statements 1 and 2 combined There are several values of x that satisfy BOTH statements. Here are two: Case a: x = 222. In this case, the answer to the target question is YES, x IS even Case b: x = 121. In ...” June 18, 2018 Brent@GMATPrepNow posted a reply to Which of the following is NOT a possible value of in the Problem Solving forum “When we scan the answer choices, we can see that 1/(4-x) can never equal 0. To see why, take 1/(4-x) = 0 and multiply each side by (4-x) to get: 1 = 0, doesn''t work. Answer: C B) 4/17 Let 1/(4-x) = 4/17 Cross multiply to get: (1)(17) = (4)(4 - x) Expand: 17 = 16 - 4x Subtract 16 ...” June 18, 2018 Brent@GMATPrepNow posted a reply to Is a positive? in the Data Sufficiency forum “All values (positive or negative) of a will satisfy the equation a - a = 0 For example, if a = 3, then we get: 3 - 3 = 0 (works!) Conversely, if a = -3, then we get: -3 - (-3) = 0 (works!) And, if a = 0, then we get: 0 - 0 = 0 (works!) Cheers, Brent” June 18, 2018 Brent@GMATPrepNow posted a reply to Is a positive? in the Data Sufficiency forum “Target question: Is a positive? Jump straight to.... Statements 1 and 2 combined There are infinitely many values of a that satisfy BOTH statements. Here are two: Case a: a = 1 (this satisfies BOTH statements). In this case, the answer to the target question is YES, a IS positive Case ...” June 18, 2018 Brent@GMATPrepNow posted a reply to The size of a television screen is given as the length in the Problem Solving forum “Let x be the length (and width) of the square screen with diagonal 21 The area of the large screen will be x² Let y be the length (and width) of the square screen with diagonal 19 The area of the small screen will be y² Our goal is to find the value of x² - y² Large TV: If we examine ...” June 18, 2018 beatthegmat started following jdiddy June 18, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: Each edge of the above cube has length 1 in the Problem Solving forum “https://i.imgur.com/pCPvPai.png Each edge of the above cube has length 1. If an ant walks from point A to point B along the OUTSIDE of the cube, what is shortest distance the ant must travel? A) √3 B) 2 C) √5 D) √6 E) √7 Answer: C Difficulty level: 700+ Source: ...” June 17, 2018 Brent@GMATPrepNow posted a reply to Permutations/Combinations in the Problem Solving forum “Take the task of distributing the 12 books and break it into stages Let''s say the children are named A, B and C Stage 1: Select 4 books to give to child A Since the order in which we select the 4 books does not matter, we can use combinations. We can select 4 books from 12 books in 12C4 ...” June 16, 2018 Brent@GMATPrepNow posted a reply to Probability in the Problem Solving forum “First, if P(test) = 1/5, then p(NO test) = 1 - 1/5 = 4/5 NOTE: questions with "at least" are often great candidates for using the complement. That is: P(Event A occurs) = 1 - P(Event A does not occur) So, P(miss at least 1 test) = 1 - P(miss no tests) P(miss no tests) P(miss no ...” June 16, 2018 Brent@GMATPrepNow posted a reply to Probability in the Problem Solving forum “P(all 3 are same type) = P(all 3 are tennis OR all 3 are cricket OR all 3 are squash) = P(all 3 are tennis) + P(all 3 are cricket) + P(all 3 are squash) = P(1st is tennis AND 2nd is tennis AND 3rd is tennis) + (1st is cricket AND 2nd is cricket AND 3rd is cricket) + P(1st is squash AND 2nd is ...” June 16, 2018 Brent@GMATPrepNow posted a reply to w, x, y and z are positive integers such that y < z < in the Data Sufficiency forum “Target question: What is the value of x? Given: w, x, y and z are positive integers such that y < z < x < w. When w is divided by x, the quotient is y, and the remainder is z. Statement 1: The least common multiple of w and x is 30 There are several values of w and x that ...” June 15, 2018 Brent@GMATPrepNow posted a reply to Is y = 7? in the Data Sufficiency forum “Target question: Is y = 7? Statement 1: (x - 4) = 0 This tells us that x = 4, but it provides no information about the value of y Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: (x - 3)(y - 7) = 0 This tells us that EITHER x = 3 OR y ...” June 15, 2018 Brent@GMATPrepNow posted a reply to In a certain sequence term_1 = 64 in the Problem Solving forum “Let''s list a few terms and look for a pattern term1 = 64 = 2^8 term2 = (2^8)(2^2) term3 = (2^8)(2^2)(2^3) term4 = (2^8)(2^2)(2^3)(2^4) . . . term8 = (2^8)(2^2)(2^3)(2^4)(2^5)(2^6)(2^7)(2^8) . . . term11 = (2^8)(2^2)(2^3)(2^4)(2^5)(2^6)(2^7)(2^8)(2^9)(2^10)(2^11) So, ...” June 15, 2018 Brent@GMATPrepNow posted a reply to If |x - 2| = |x + 3|, x could equal in the Problem Solving forum “There are 3 steps to solving equations involving ABSOLUTE VALUE: 1. Apply the rule that says: If |x| = k, then x = k and/or x = -k 2. Solve the resulting equations 3. Plug solutions into original equation to check for extraneous roots Given: |x - 2| = |x + 3| case a: x - 2 = x + 3 Subtract ...” June 15, 2018 Brent@GMATPrepNow posted a reply to $\sqrt{16+16}=$ in the Problem Solving forum June 15, 2018 Brent@GMATPrepNow posted a reply to $\sqrt{16+16}=$ in the Problem Solving forum “Useful rule: √(xy) = (√x)(√y) So, √(16 + 16) = √(32) = √(16 x 2) = √16 x √2 = 4 x √2 = 4√2 Answer: A Cheers, Brent” June 15, 2018 Brent@GMATPrepNow posted a reply to If n is the product of the squares of 4 different prime numb in the Problem Solving forum “-----------ASIDE------------------ If the prime factorization of N = (p^a)(q^b)(r^c) . . . (where p, q, r, etc are different prime numbers), then N has a total of (a+1)(b+1)(c+1)(etc) positive divisors. Example: 14000 = (2^4)(5^3)(7^1) So, the number of positive divisors of 14000 = ...” June 15, 2018 Brent@GMATPrepNow posted a reply to Is x > 0 ? in the Data Sufficiency forum “Target question: Is x > 0 ? Let''s go straight to... Statements 1 and 2 combined Statement 1 tells us that x < x² Statement 2 tells us that x < x³ There are several values of x that satisfy BOTH statements. Here are two: Case a: x = 2. Notice that 2 < 2² AND 2 < 2³. ...” June 14, 2018 Brent@GMATPrepNow posted a reply to If x and y are prime numbers, and n is a positive integer, w in the Data Sufficiency forum “-------ASIDE---------------- If the prime factorization of N = (p^a)(q^b)(r^c) . . . (where p, q, r, etc are different prime numbers), then N has a total of (a+1)(b+1)(c+1)(etc) positive divisors. Example: 14000 = (2^4)(5^3)(7^1) So, the number of positive divisors of 14000 = (4+1)(3+1)(1+1) ...” June 14, 2018 June 14, 2018 Brent@GMATPrepNow posted a reply to x and y are integers such that 4x^2 – y^2 +4x + 4y – 3 = in the Problem Solving forum “Let''s examine the expression in parts 4x² is EVEN for all integer values of x y² not sure 4x is EVEN for all integer values of x 4y is EVEN for all integer values of y 3 is ODD 0 is EVEN So, we get: EVEN – y² + EVEN + EVEN – ODD = EVEN Simplify left side: ODD – y² = EVEN ...” June 14, 2018 Brent@GMATPrepNow posted a reply to On July 1, 2017, a certain tree was 128 centimeters tall. Ea in the Problem Solving forum “Let''s create a growth table and look for a pattern year | height in cm 2017: 128 2018: 128(1.5) 2019: 128(1.5)^2 2020: 128(1.5)^3 2021: 128(1.5)^4 2022: 128(1.5)^5 2023: 128(1.5)^6 The tree''s height on July 1, 2023 will be how many centimeters greater than the tree''s height on July ...” June 14, 2018 Brent@GMATPrepNow posted a reply to The sum of 3 consecutive numbers is definitely: in the Problem Solving forum “Another approach: Let x = the smallest integer So, x+1 = the next integer And x+2 = the last integer Sum of 3 consecutive numbers = x + (x+1) + (x+2) = 3x + 3 = 3(x+1) As we can see, the sum MUST be a multiple of 3 Or we can say the sum MUST be a divisible by 3 Answer: C ...” June 13, 2018 Brent@GMATPrepNow posted a reply to N is a 3-digit number, and the sum of its digits is 10. When in the Data Sufficiency forum “Target question: What is the value of N? Given: N is a 3-digit number, and the sum of its digits is 10. When the digits of N are reversed, the new number is 99 less than N. Let N = wxy, where w, x and y represent the 3 digits in N So, the first equation we can write is: w + x + y = 10 ...” June 13, 2018 Brent@GMATPrepNow posted a new topic called In a certain sequence term_1 = 64 in the Problem Solving forum “In a certain sequence, term1 = 64, and for all n > 1, termn = (2^n)(termn-1) What is the value of term11/term8 ? A) 2^3 B) 2^6 C) 2^9 D) 2^27 E) 2^30 Answer: E Difficulty level: 600 - 650 Source: www.gmatprepnow.com * I''ll provide a solution in 2 days” June 13, 2018 Brent@GMATPrepNow posted a new topic called w, x, y and z are positive integers such that y < z < x < w. in the Data Sufficiency forum “w, x, y and z are positive integers such that y < z < x < w. When w is divided by x, the quotient is y, and the remainder is z. What is the value of x? (1) The least common multiple of w and x is 30 (2) x³ – 8x² + 12x = 0 Answer: B Difficulty level: 700+ Source: ...” June 13, 2018 Brent@GMATPrepNow posted a reply to A 75-liter solution of cool-drink is made from 8% jasmine in the Problem Solving forum “Your solution isn''t quite correct. A 75-liter solution of cool-drink is made from 8% jasmine water. 8% of 75 = (8/100)(75) = 6 So, the 75 liters is comprises of 6 liters of jasmine If 3 liters of jasmine and 12 liters of water were added to the solution.... We adding 15 liters, so the NEW ...” June 12, 2018 Brent@GMATPrepNow posted a new topic called On July 1, 2017, a certain tree was 128 centimeters tall. Ea in the Problem Solving forum “On July 1, 2017, a certain tree was 128 centimeters tall. Each year, the tree''s height increases 50%. Given this growth rate, the tree''s height on July 1, 2023 will be how many centimeters greater than the tree''s height on July 1, 2022? A) (2^2)(3^4) B) (2)(3^4) C) (2)(3^5) D) (4)(3^5) ...” June 12, 2018 Brent@GMATPrepNow posted a reply to tricky challenge question - Is CB || ED? in the Data Sufficiency forum “Target question: Is CB || ED? Let''s jump straight to.... Statements 1 and 2 combined Statement 1 tells us that ∆ABC and ∆AED are both isosceles triangles Statement 2 tells us that ∠C = ∠E Let''s start with 2 identical isosceles triangles: https://i.imgur.com/IQe4Cwq.png ...” June 12, 2018 Brent@GMATPrepNow posted a new topic called N is a 3-digit number, and the sum of its digits is 10. When in the Data Sufficiency forum “N is a 3-digit number, and the sum of its digits is 10. When the digits of N are reversed, the new number is 99 less than N. What is the value of N? (1) The hundreds digit of N is 1 more than its units digit. (2) The tens digit of N is 2 more than its hundreds digit. *solution posted in 2 ...” June 11, 2018 Brent@GMATPrepNow posted a reply to If n is the sum of the first 50 positive integers, what is t in the Problem Solving forum “Alternatively, we can use the following formula: Sum of the first k positive integers = (k)(k+1)/2 For example, the sum of the first 10 positive integers = (10)(10 + 1)/2 = 55 So, the sum of the first 50 positive integers = (50)(50 + 1)/2 = (50)(51)/2 = (25)(51) = (5)(5)(3)(17) Answer: ...” June 11, 2018 Brent@GMATPrepNow posted a reply to If n is the sum of the first 50 positive integers, what is t in the Problem Solving forum “n = 1 + 2 + 3 + 4 + ...... + 47 + 48 + 49 + 50 Let''s add the values in pairs, starting from the outside and work towards the middle n = (1 + 50) + (2 + 49) + (3 + 48) + . . .. = 51 + 51 + 51 + ..... Since we are adding 50 values (from 1 to 50), we will get 25 PAIRS of values So, n = ...” June 11, 2018 Brent@GMATPrepNow posted a reply to What is the value of x/3+y/3? in the Data Sufficiency forum “Target question: What is the value of x/3 + y/3? Statement 1: (x + y)/3 = 6 Nice (and often tested) rule: (a + b)/c = a/c + b/c So, we can rewrite the equation as: x/3 + y/3 = 6 So, the answer to the target question is x/3 + y/3 = 6 Since we can answer the target question with certainty, ...” June 11, 2018 Brent@GMATPrepNow posted a reply to work in the Problem Solving forum “Starting point: 3 men, 4 women and 6 children A child does half the work a man does. In other words, 1 child = 1/2 a man This means 6 children = 3 men So, let''s just REPLACE the 6 children with 3 men to get: 6 men and 4 women A woman does double the work a man does In other words, 1 ...” June 11, 2018 Brent@GMATPrepNow posted a reply to In the above diagram, the circle inscribes the larger in the Problem Solving forum “Another approach is to use the following fact: For GMAT Problem Solving questions (i.e., questions that are NOT data sufficiency questions), all diagrams are DRAWN TO SCALE, unless stated otherwise. So, we can use this to ESTIMATE the area of the larger triangle. We know the smaller ...” June 10, 2018 Brent@GMATPrepNow posted a reply to In the above diagram, the circle inscribes the larger in the Problem Solving forum “We''re told that the area of the smaller triangle is √3 USEFUL FORMULA: Area of an equilateral triangle = (√3)(side²)/4 So, we can write: (√3)(side²)/4 = √3 Divide both sides by √3 to get: (side²)/4 = 1 Multiply both sides by 4 to get: side² = 4 Solve: side = 2 So, each side of ...” June 10, 2018 Brent@GMATPrepNow posted a reply to John traveled 80% of the way from Yellow-twon to Green- in the Problem Solving forum “Your solution is great. Another option would be to test the answer choices. Cheers, Brent” June 10, 2018 Brent@GMATPrepNow posted a new topic called tricky challenge question - Is CB || ED? in the Data Sufficiency forum “https://i.imgur.com/QY581Gp.png Is CB || ED? (1) ∆ABC and ∆AED are both isosceles triangles (2) ∠C = ∠E” June 10, 2018 Brent@GMATPrepNow posted a reply to If x > 0, b > a, and 2x + 5 < 3x + 1, then which of in the Problem Solving forum “Here''s a useful triangle property: https://i.imgur.com/dLnB7G2.png So, if b > a, then we know that 3x + 1 < 4x - 8 We''re also told that 2x + 5 < 3x + 1 So, we can create the following 3-part inequality: 2x + 5 < 3x + 1 < 4x - 8 Subtract 2x from all 3 sides: 5 < x + 1 ...” June 9, 2018 beatthegmat posted a new topic called Is The GMAT Stopping You From An MBA? in the The Application Process forum “https://s33.postimg.cc/mgtq5l3jf/gmat.png Not everyone is good at taking tests. Especially when you feel as if your entire career is resting on the results of four hours spent in an airless room with dozens of other people who look cool, calm and collected while you’re sweating through ...” June 8, 2018 Brent@GMATPrepNow posted a reply to If the sum of the minimum and the maximum of 7 consecutive o in the Problem Solving forum “One more (longer!) solution. Let x = smallest ODD integer So, x+2 = next (2nd) ODD integer x+4 = next (3rd) ODD integer . . . x + 12 = largest (7th) ODD integer Sum of the minimum and the maximum is 114 So, x + x + 12 = 114 Simplify: 2x + 12 = 114 So, 2x = 102 Solve: x = 51 ...” June 8, 2018 Brent@GMATPrepNow posted a reply to If x and y are integers, and x/y = 1.64, which in the Problem Solving forum “Given: x/y = 1.64 Rewrite as: x/y = 164/100 Simplify: x/y = 41/25 So, it''s possible that x = 41 and y = 25 We can also create infinitely many fractions that are EQUIVALENT to 41/25 For example, we can take 41/25 and multiply top and bottom by 2 to get: 82/50 So, it''s possible that x = 82 ...” June 8, 2018 Brent@GMATPrepNow posted a reply to Train X leaves New York at 1 A.M. and travels east at a in the Problem Solving forum “Train X leaves at 1 A.M. and Train Z leaves New York at 2 A.M. When they meet at 5:30 A.M., Train X''s travel time will be 4.5 hours, and Train Z''s travel time will be 3.5 hours Also recognize that, when the trains meet, they both will have traveled the same distance. We know that Train X ...” June 8, 2018 Brent@GMATPrepNow posted a new topic called In the above diagram, the circle inscribes the larger in the Problem Solving forum “https://i.imgur.com/BywBeDq.png In the above diagram, the circle inscribes the larger equilateral, and it circumscribes the smaller equilateral triangle. If the area of the smaller triangle is √3, what is the area of the larger triangle? A) 9π - 16√3 B) 4√3 C) 8√3 D) 16√3 E) ...” June 8, 2018 Brent@GMATPrepNow posted a reply to On entering the stadium, cheers greeted them in the Sentence Correction forum “A. On entering the stadium, cheers greeted them We get: ...cheers greeted them as a sign of universal approval... So, the PEOPLE were a sign of approval? This doesn''t make sense. The CHEERS were a sign of approval. ELIMINATE A ELIMINATE D and E for the same reason. B. On entering the ...” June 7, 2018 Brent@GMATPrepNow posted a reply to inference in the Critical Reasoning forum “When answering inference questions on the GMAT, are looking for the answer choice that MUST follow from the premises. So, as we examine the answer choices, we must aggressively eliminate any answer choice that does not necessarily follow from the premises. (A) Individuals who are underweight do ...” June 7, 2018 Brent@GMATPrepNow posted a reply to One gallon of soft drink is made of 40% orange juice and 60% in the Problem Solving forum “IMPORTANT CONCEPT: when we combine EQUAL amounts of two mixtures, the concentration of the resulting mixture will be the AVERAGE of the two mixtures. For example, if we combine 1 liter of a 10% salt solution with 1 liter of a 40% salt solution, the RESULTING solution will be 25% salt, since ...” June 7, 2018 Brent@GMATPrepNow posted a reply to When positive integer N is divided by 18, the remainder is x in the Problem Solving forum “Let''s examine each statement separately... i) x = 9 and y = 3 Let''s come up with a value of N that satisfies this condition. How about N = 9? 9 divided by 18 = 0 with remainder 9 (i.e., x = 9) ...and 9 divided by 6 = 1 with remainder 3 (i.e., y = 3) Perfect, statement i is TRUE Check the ...” June 7, 2018 Brent@GMATPrepNow posted a new topic called If x > 0, b > a, and 2x + 5 < 3x + 1, then which of the in the Problem Solving forum “https://i.imgur.com/jteIDVs.png If x > 0, b > a, and 2x + 5 < 3x + 1, then which of the following COULD be a value of x? i) 4.39 ii) 7.17 iii) 9.27 A) i and ii only B) ii and iii only C) i and iii only D) iii only E) i, ii and iii Answer: D Difficulty level: 600 – ...” June 7, 2018 Brent@GMATPrepNow posted a reply to In the coordinate plane, is the x-intercept of the line ax + in the Data Sufficiency forum “Target question: Is the x-intercept less than 0? This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: The x-intercept is the point where a line crosses the x-axis. At this point, the y-coordinate is ZERO So, the ...” June 6, 2018 Brent@GMATPrepNow posted a reply to $\frac{49^2-35^2}{14}=$ in the Problem Solving forum “My bad. Here''s the video for squaring numbers that end in 5: https://www.gmatprepnow.com/module/gmat-powers-and-roots/video/1024 Cheers, Brent” June 6, 2018 Brent@GMATPrepNow posted a reply to How many of the positive divisors of 120 are also multiples in the Problem Solving forum “Alternatively, we can just list all divisors in an systematic fashion. We''ll list the divisors in PAIRS of numbers that have a product of 120: 1 and 120 2 and 60 3 and 40 4 and 30 5 and 24 6 and 20 8 and 15 10 and 12 DONE Scanning our list, the multiples of 4 are in red There are 7 ...” June 6, 2018 Brent@GMATPrepNow posted a reply to Rene aerns$8.50 per hour on days other than Sundays and in the Problem Solving forum
“Your solution is great. Here''s one small tip for reducing your calculations by one. Once we know that Rene''s earnings = (32)(8.5) + (8)(17), we can use a nice technique called "Multiplication by Halving and Doubling" It goes like this: AB = (A/2)(2B) For example: (18)(3.5) = ...”
June 6, 2018
Brent@GMATPrepNow posted a new topic called If x and y are integers, and x/y = 1.64, which in the Problem Solving forum
“If x and y are integers, and x/y = 1.64, which of the following CANNOT be a value of x? A) -656 B) -82 C) 123 D) 205 E) 288 Answer: E Difficulty level: 550 – 600 Source: www.gmatprepnow.com”
June 6, 2018
beatthegmat posted a new topic called Your Business School Application: 4 Things to Do Right Now in the The Application Process forum
“Congratulations on the decision to pursue a professional business degree! Are you wondering where to start? Applying to MBA and specialized master’s programs requires careful planning and preparation. Checking these first tasks off your list can help put you on the path to success. 1. Know your ...”
June 5, 2018
Brent@GMATPrepNow posted a reply to 30^20 – 20^20 is divisible by all in the Problem Solving forum
“Here are some useful divisibility rules: 1. If integers A and B are each divisible by integer k, then (A + B) is divisible by k 2. If integers A and B are each divisible by integer k, then (A - B) is divisible by k 3. If integer A is divisible by integer k, BUT integer B is NOT divisible by ...”
June 5, 2018
Brent@GMATPrepNow posted a new topic called When positive integer N is divided by 18, the remainder is x in the Problem Solving forum
“When positive integer N is divided by 18, the remainder is x. When N is divided by 6, the remainder is y. Which of the following are possible values of x and y? i) x = 9 and y = 3 ii) x = 16 and y = 2 iii) x = 13 and y = 7 A) i only B) i and ii only C) i and iii only D) ii and iii only ...”
June 5, 2018
Brent@GMATPrepNow posted a reply to A straight line has a slope of 1/2 and a y-intercept of in the Problem Solving forum
“Given this information, we can write the equation for the line in slope y-intercept form, y = mx + b, where m = the slope and b = the y-intercept We''re told that the slope is 1/2 and the y-intercept is -2 So, the equation of the line is: y = (1/2)x + (-2) Simplify to get: y = (1/2)x - 2 ...”
June 5, 2018
Brent@GMATPrepNow posted a reply to If -10 < k < 10, is k > 0? in the Data Sufficiency forum
“Target question: Is k > 0 Given: -10 < k < 10 Statement 1: 1/k > 0 In other words, 1/k is POSITIVE Since 1 is positive, we can write: POSITIVE/k = POSITIVE From this, we can conclude that k must be POSITIVE So, the answer to the target question is YES, it is the case that ...”
June 5, 2018
Brent@GMATPrepNow posted a reply to If 2x = 3y = 10, then 12xy = ? in the Problem Solving forum
“Mitch has already demonstrated the fastest/best approach, but even if you didn''t see that approach, we can always solve the question by first solving the equations for x and y. Here''s what I mean..... GIVEN: 2x = 10 Solve to get: x = 5 GIVEN: 3y = 10 Solve to get: y = 10/3 So, 12xy ...”
June 5, 2018
Brent@GMATPrepNow posted a reply to When x and n are positive integers, if x^{2n}>(3x)^n, whi in the Problem Solving forum
“Let''s find some values that satisfy the given condition that x^{2n} > (3x)^n How about x = 4 and n = 1. When we plug in these values we get: 4^2 > 12^1, which simplifies to 16 > 12. PERFECT. Which of the following must be true? A. x>3 One possible solution is n = 4. This ...”
June 4, 2018
Brent@GMATPrepNow posted a reply to progressions in the Problem Solving forum
“What''s the source of this question? It''s very un-GMAT-like. First, students aren''t required to know what an A.P. is. Second, {19, 19/5, 87/5,...} this is not an arithmetic progression (A.P.). Third, what do you mean by "maximum sum"? Are you thinking of an infinite GEOMETRIC ...”
June 4, 2018
Brent@GMATPrepNow posted a reply to A certain team consists of 4 professors and 6 teaching in the Problem Solving forum
“When we see a counting question involving "at least", we should consider using the nice rule: Total number of outcomes that FOLLOW a rule = (TOTAL number of outcomes that IGNORE the rule) - (number of outcomes that BREAK the rule) Here, we have: Total number of teams with AT LEAST one ...”
June 4, 2018
Brent@GMATPrepNow posted a reply to progressions in the Data Sufficiency forum
“Please note that the GMAT test-makers don''t assume that students know what an arithmetic progression is. In the past, when they''ve used the term "arithmetic sequence", they have also defined the term. Cheers, Brent”
June 4, 2018
Brent@GMATPrepNow posted a reply to If m = 0.008163 and M the decimal obtained by rounding m to in the Problem Solving forum
“Given: m = 0.008163 The digit 1 is in ten thousandth place of 0.008163 Since next digit (in the hundred thousandth position) is greater than 4, we must ROUND UP So, when we round 0.008163 to the nearest to ten thousandth, we get: 0.0082 In other words, M = 0.0082 So, M + m = 0.0082 + ...”
June 4, 2018
Brent@GMATPrepNow posted a reply to If P, Q, and R are distinct positive digits and the product in the Problem Solving forum
“That''s a perfect approach. The hardest part is looking for two 2-digit numbers that have a product of 221!! Cheers, Brent”
June 4, 2018
Brent@GMATPrepNow posted a reply to On a road trip, Kip drove one-quarter the distance at an ave in the Problem Solving forum
“Since we aren''t told the total distance, let''s assign a nice value to the distance. Let''s say 32 miles = TOTAL distance. So, each quarter = 8 miles Average speed = total distance/total travel time So, we must find the travel time for EACH QUARTER and add them together. Time = ...”
June 4, 2018
Brent@GMATPrepNow posted a reply to If 2/a+3/a+4/a is an integer, which of the following must in the Problem Solving forum
“That''s a perfect approach. 2/a+3/a+4/a = 9/a. So, if 2/a+3/a+4/a is an integer, then 9/a must be an integer as well. Another approach would be to use the fact that the question asks "Which of the following must also be an integer?" So, first find a value of a so that 2/a+3/a+4/a ...”
June 4, 2018
Brent@GMATPrepNow posted a new topic called 30^20 – 20^20 is divisible by all in the Problem Solving forum
“30^20 – 20^20 is divisible by all of the following values, EXCEPT: A) 10 B) 25 C) 40 D) 60 E) 64 Answer: D Difficulty level: 600 – 650 Source: www.gmatprepnow.com”
June 4, 2018
Brent@GMATPrepNow posted a new topic called On a road trip, Kip drove one-quarter the distance at an ave in the Problem Solving forum
“On a road trip, Kip drove one-quarter the distance at an average speed of v miles per hour, one-quarter the distance at an average speed of 2v miles per hour, one-quarter the distance at 4v miles per hour, and one-quarter the distance at 8v miles per hour. In terms of v, what was Kip’s average ...”
June 3, 2018
Brent@GMATPrepNow posted a reply to inequality in the Data Sufficiency forum
“Target question: Is the product cd positive? Statement 1: 3c = -8d³ Divide both sides by d to get: 3c/d = -8d² Divide both sides by 3 to get: c/d = -8d²/3 Rewrite as: c/d = (-8/3)(d²) Since d² is greater than or equal to zero for all values of d, and since -8/3 is NEGATIVE, we can ...”
June 3, 2018
Brent@GMATPrepNow posted a reply to Last year the price per share of Stock X increased by k % in the Problem Solving forum
“One approach is to plug in values. Let $100 be the original price per share of Stock X Choose a "nice" value for k. How about k = 200 So, after a 200% increase, the new price per share =$300 Let \$100 be the original earnings per share of Stock X Choose a "nice" ...”
June 3, 2018
Brent@GMATPrepNow posted a new topic called What is the volume of the largest cube that can in the Problem Solving forum
“What is the volume of the largest cube that can fit inside a cylinder with radius 2 and height 3? A) 9 B) 8√2 C) 16 D) 16√2 E) 27 Answer: D Difficulty level: 650 – 700 Source: www.gmatprepnow.com”
June 2, 2018
Brent@GMATPrepNow posted a reply to Set X contains 10 consecutive integers. If the sum of the in the Problem Solving forum
“-------ASIDE------------------------------------------- Notice that we can write the first 10 consecutive integers as follows: 1, 2, 3, 4, 5, (1 + 5), (2 + 5), (3 + 5), (4 + 5), (5 + 5) So, the sum of the first 5 integers = 1 + 2 + 3 + 4 + 5 The sum of the last 5 integers = (1 + 5) + (2 + ...”
June 2, 2018
Brent@GMATPrepNow posted a reply to If 2^x = 5 and 4^y = 20, what is the in the Problem Solving forum
“Here''s a totally different approach: GIVEN: 2^x = 5 2^2 = 4 and 2^3 = 8 Since 5 is BETWEEN 4 and 8, we know that x is BETWEEN 2 and 3. From here, we can estimate. Since 5 is closer to 4 than it is to 8, we know that x will be closer to 2 than it is to 3. Let''s say that x ≈ 2.3 ...”
June 2, 2018
Brent@GMATPrepNow posted a reply to If 2^x = 5 and 4^y = 20, what is the in the Problem Solving forum
“There are several approaches we can take. Here''s the algebraic approach: Given: 2^x = 5 and 4^y = 20 Take second equation and rewrite 4 as 2² to get: (2²)^y = 20 Simplify to get: 2^(2y) = 20 We now have: 2^(2y) = 20 2^x = 5 This means we can write: 2^(2y)/2^x = 20/5 Simplify: 2^(2y ...”
June 2, 2018
Brent@GMATPrepNow posted a reply to If x^2-5x+6=2|x-1|, what is the product of all in the Problem Solving forum
“Your approach is perfect. HOWEVER, once you determine that the solutions are x = 1, x = 3 and x = 5, you must then plug those values back into the original equation (x² - 5x + 6 = 2 - |x - 1| ) to identify any EXTRANEOUS roots. Let''s do that x = 1 Plug into the original equation to get: ...”
June 1, 2018
Brent@GMATPrepNow posted a reply to A car travels from point A to B. The average speed of the in the Problem Solving forum
“There''s a bit of ambiguity here. If the first half of the trip is spent at one speed, and the second half is spent at another speed, are we referring to half the total DISTANCE, or half the total TIME. For example, if it takes 10 hours to drive 200 miles, some people might refer to the first ...”
June 1, 2018
Brent@GMATPrepNow posted a new topic called If 2^x = 5 and 4^y = 20, what is the in the Problem Solving forum
“If 2^x = 5 and 4^y = 20, what is the value of x in terms of y? A) y – 2 B) (y + 1)/2 C) 2y – 2 D) y/2 – 2 E) 2y + 2 Answer: C Difficulty level: 600 – 650 Source: www.gmatprepnow.com”
June 1, 2018
Brent@GMATPrepNow posted a reply to Is integer x odd? in the Data Sufficiency forum
“Target question: Is integer x odd? Statement 1: 2x + 1 is odd Since 2x + 1 is ODD for any integer value, this statement doesn''t tell us anything. To understand what I mean, consider these two cases that satisfy statement 1: Case a: x = 1. Here, 2x + 1 = 2(1) + 1 = 3, which is odd. In ...”
June 1, 2018
Brent@GMATPrepNow posted a reply to Today Jim is twice as old as Fred, and Sam is 2 years in the Problem Solving forum
“TODAY''S AGES Today Jim is twice as old as Fred, and Sam is 2 years younger than Fred. Let x = Fred''s age TODAY So, 2x = Jim''s age TODAY And x - 2 = Sam''s age TODAY AGES FOUR YEARS AGO Let''s first determine Jim''s age and Sam''s age FOUR YEARS AGO If 2x = Jim''s age TODAY, then 2x - 4 ...”
June 1, 2018
beatthegmat started following pgupta
June 1, 2018
Brent@GMATPrepNow posted a reply to A data set consists of three integers. What is the standard in the Data Sufficiency forum
“Target question: What is the standard deviation of the 3-integer data set? Statement 1: The average (arithmetic mean) and the median are both 3 Let''s TEST some values. There are several sets that satisfy statement 1. Here are two: Case a: {3, 3, 3}. Notice that the median and mean both ...”
June 1, 2018
Brent@GMATPrepNow posted a reply to ratios in the Problem Solving forum
“I think the fast way is to plug in some nice numbers. Since the two pieces of information regarding the night shift are related to the information regarding the day shift, let''s assign some nice values to the DAY shift. Number of workers Day shift: 5 workers (this is an easy number to find ...”
May 31, 2018
Brent@GMATPrepNow posted a new topic called J = x rounded to the nearest TENTH, and K = x rounded to the in the Problem Solving forum
“J = x rounded to the nearest TENTH, and K = x rounded to the nearest THOUSANDTH. If 0 < x < 1, what is the greatest possible value of J – K? A) 0.005 B) 0.0055 C) 0.05 D) 0.0505 E) 0.0555 Answer: C Difficulty level: 650 – 700 Source: www.gmatprepnow.com”
May 31, 2018
Brent@GMATPrepNow posted a reply to If each of the 4 circles above has radius 1, what in the Problem Solving forum
“Here''s a different approach: Let''s place a square around just one of the circles https://i.imgur.com/xuhL6Te.png Notice that the shaded area IN the square represents 1/4 of the TOTAL shaded area in the diagram. https://i.imgur.com/NrpovG1.png This means that the shaded area in ...”
May 31, 2018
Brent@GMATPrepNow posted a reply to $\frac{49^2-35^2}{14}=$ in the Problem Solving forum
“Vincen has demonstrated the approach I would have used. But, for "fun," here''s another approach. First, you need to know a nice trick for squaring numbers that end in 5 (the trick takes 2 minutes to learn, and then you can perform calculations like 65² and 35² in 5 seconds. Here''s ...”
May 31, 2018
Brent@GMATPrepNow posted a reply to Is 0.4 < x < 0.8? in the Data Sufficiency forum
“Target question: Is 0.4 < x < 0.8? Statement 1: 407x < 376 Divide both sides of the inequality by 407 to get: x < 376/407 Convert to a decimal to get: x < 0.92 There are several values of x that satisfy statement 1. Here are two: Case a: x = 0.6. In this case, the answer ...”
May 31, 2018
Brent@GMATPrepNow posted a reply to Is x+y > 0? in the Data Sufficiency forum
“Target question: Is x+y > 0? Statement 1: x > y Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 2 and y = 1 (this satisfies the condition that x > y). In this case, x + y = 2 + 1 = 3. So, the answer to the target ...”
May 31, 2018
Brent@GMATPrepNow posted a reply to If [x] is the greatest integer less than or equal to x, what in the Problem Solving forum
“, not 3 Cheers, Brent”
May 30, 2018
Brent@GMATPrepNow posted a reply to If the distances between each pair of consecutive ticks are in the Problem Solving forum
“If the distances between each pair of consecutive ticks are equal, we can write: 2^11 - 2^10 = x - 2^11 We must solve this equation for x.... Add 2^11 to both sides: 2^11 + 2^11 - 2^10 = x Combine the two 2^11''s to get: 2(2^11) - 2^10 = x Rewrite 2 as 2^1 to get: (2^1)(2^11) - 2^10 = x ...”
May 30, 2018
Brent@GMATPrepNow posted a new topic called Challenge question: On the x-y coordinate plane, lines j and in the Data Sufficiency forum
“Challenge question On the x-y coordinate plane, lines j and k intersect at one point. If the equation of line j is bx + ay = 5, and the equation of line k is 2bx - 3ay = -5, what is the value of a + b? (1) Lines j and k intersect at (1, -3). (2) a - b = -3 Answer A Difficulty ...”
May 30, 2018
Brent@GMATPrepNow posted a reply to For what value of x are the mode, the median and the average in the Problem Solving forum
“I sincerely doubt that there''s a better (i.e., faster) approach than the one you describe. One option would be to test the answer choices, but your approach is likely faster. The key concept (which you have identified) is that the mode MUST be 60, since we already have two 60''s. Cheers, ...”
May 30, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive integers less than 10, which in the Problem Solving forum
“When I scan the statements, I see that ii and iii look easier, so I''ll start with those. ii) y√x = x√y We can quickly see that, if x = y, then this statement is TRUE. For example, if x = 1 and y = 1, we get 1√1 = 1√1, which is true. So, statement ii COULD be true. Check the ...”
May 30, 2018
Brent@GMATPrepNow posted a reply to Is the positive integer P a multiple of 11 [A] P = M+N in the Data Sufficiency forum
“Target question: Is P a multiple of 11 Statement 1: P = M+N where M and N are integers Definitely NOT SUFFICIENT Statement 2: M is divisible by 11 and N is not divisible by 11 Since there''s no information about P, there''s no way to answer the target question Statement 2 is NOT ...”
May 30, 2018
Brent@GMATPrepNow posted a reply to Which of the following fractions has the greatest value? (A in the Problem Solving forum
“We might also make things easier by getting rid of the fractions by multiplying all of the values by the lowest common denominator, which is (3^4)(5^5) let'' s do this... (A) 1/(3^2)(5^2) x (3^4)(5^5) = (3^2)(5^3) = (9)(125) (B) 2/(3^2)(5^2) x (3^4)(5^5) = (2)(3^2)(5^3) = (2)(9)(125) (C) ...”
May 30, 2018
Brent@GMATPrepNow posted a reply to Mode in the Problem Solving forum
“This comes down to the distinction between "the mode" and "a mode" The mode of a set of 4 positive integers is 7. This suggests that there is only 1 mode. ASIDE: In the set {1, 2, 4, 4}, there''s one mode: 4 In the set {3, 3, 4, 4}, there are two modes: 3 and 4 In the ...”
May 29, 2018
Brent@GMATPrepNow posted a new topic called If each of the 4 circles above has radius 1, what in the Problem Solving forum
“https://i.imgur.com/bzRq3H2.png If each of the 4 circles above has radius 1, what is the area of the shaded region? A) 1 – π/4 B) 2 – π/4 C) 2 – π/2 D) 4 – π E) 4 – 2π Answer: D Difficulty level: 700+ Source: www.gmatprepnow.com”
May 29, 2018
Brent@GMATPrepNow posted a reply to If x is a positive integer, which of the following COULD in the Problem Solving forum
“There''s a triangle property that says: (length of LONGEST side) < (SUM of the other two lengths) So, for example, 2, 3, 6 CANNOT be the lengths of sides in a triangle, because 6 > 2 + 3 i) x, 2x + 2, x + 2 Since x is a positive integer, we can see that 2x+2 will be the LONGEST side. ...”
May 28, 2018