## 800guy

Brent@GMATPrepNow posted a new topic called Joe’s restaurant has exactly 3 items on its menu in the Data Sufficiency forum
“Joe’s restaurant has exactly 3 items on its menu: Prawns Only meal, Steak Only meal, and Steak & Prawns meal. If the kitchen has 592 prawns and 30 pounds of steak, can it make at least 100 meals? (1) Each Prawns Only meal requires 15 prawns (2) Each Steak Only meal requires 0.62 pounds ...”
Yesterday
Brent@GMATPrepNow posted a new topic called If x, y and z are different positive integers, and y is the in the Problem Solving forum
“If x, y and z are different positive integers, and y is the greatest common divisor of x, y and z, which of the following MUST be true? i) y < x ii) the greatest common divisor of x and z is greater than y iii) the greatest common divisor of x and y is y A) ii only B) i and ii only C) i ...”
Yesterday
Brent@GMATPrepNow posted a reply to If p is a positive integer, is p even? in the Data Sufficiency forum
“Target question: Is p EVEN? ASIDE: Another way to handle statement 2 is to apply a useful rule: 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 ...”
Yesterday
Brent@GMATPrepNow posted a new topic called Joe’s restaurant has exactly 3 items on its menu: Prawns Onl in the Problem Solving forum
“Wrong forum - I''ve reposted the question is Data Sufficiency”
Yesterday
Brent@GMATPrepNow posted a reply to How many gallons of water must be mixed with 1 gallon in the Problem Solving forum
“Let x = the volume (in gallons) of water that must be added to the existing mixture. We have 1 gallon of the EXISTING mixture, which is 15% salt. 15% of 1 = 0.15 So, the EXISTING mixture contains 0.15 gallons of salt When we add x gallons of water to the existing mixture, the NEW mixture has ...”
Yesterday
Brent@GMATPrepNow posted a reply to A jar contains 6 red marbles and 9 blue marbles. If Evelyn in the Problem Solving forum
“P(both are same color) = P(1st marble is red AND 2nd marble is red OR 1st marble is blue AND 2nd marble is blue) = x P(2nd marble is red)] + x P(2nd marble is blue)] = x 5/14] + x 8/14] = x 5/14] + x 8/14] = 10/70 + 24/70 = 34/70 = 17/35 Answer: D Cheers, Brent”
May 21, 2018
Brent@GMATPrepNow posted a reply to If x = 3y = 4z, which of the following must equal 6x ? in the Problem Solving forum
“Let''s examine each statement I. 18y Given: x = 3y Multiply both sides by 6 to get: 6x = 18y Perfect! Statement I is TRUE Check the answer choices.....ELIMINATE B and C since they state that statement I is not true. II. 3y + 20z Given: x = 3y Also, since x = 4z, we can multiply both ...”
May 21, 2018
Brent@GMATPrepNow posted a reply to If A is a prime number, what is the value of A? in the Data Sufficiency forum
“Target question: What is the value of A? Given: A is a prime number Statement 1: 0 < A < 10 Let''sTEST some values. There are several values of A that satisfy statement 1. Here are two: Case a: A = 2 Case b: A = 3 Since we cannot answer the target question with certainty, ...”
May 21, 2018
Brent@GMATPrepNow posted a reply to If p is a positive integer, is p even? in the Data Sufficiency forum
“Target question: Is p even? Statement 1: p divided by 3 leaves a remainder of 1 In other words, p is 1 greater than some multiple of 3 There are several values of p that satisfy this condition. Here are two: Case a: p = 4. In this case, the answer to the target question is YES, p is even ...”
May 21, 2018
Brent@GMATPrepNow posted a new topic called If x and y are positive integers, and 4x is the least in the Problem Solving forum
“If x and y are positive integers, and 4x is the least common multiple of x and y, which of the following MUST be true? i) x is the greatest common divisor of x and y ii) x = y/4 iii) x is a multiple of 4 A) i only B) ii only C) iii only D) ii and iii only E) none Answer: E Difficulty ...”
May 21, 2018
Brent@GMATPrepNow posted a new topic called If x and y are integers, and in the Data Sufficiency forum
“If x and y are non-zero integers, and (-x)^x = y^y, what is the value of x? (1) x + y = 0 (2) x is odd Answer: E Difficulty level: 650 – 700 Source: www.gmatprepnow.com”
May 21, 2018
Brent@GMATPrepNow posted a reply to On Monday, Karen had S dollars in her savings account in the Problem Solving forum
“Monday S dollars in savings account C dollars in checking account Tuesday: Karen transferred half of the money in her savings account to her checking account Amount in savings account = 0.5S Amount in checking account = C + 0.5S Wednesday: Karen transferred 20% of the money in her checking ...”
May 21, 2018
Brent@GMATPrepNow posted a reply to Is 2 < xy < 20? in the Data Sufficiency forum
“Target question: Is 2 < xy < 20? Statement 1: -2 < x < 4 Since we have no information about the value of y, there''s no way to the target question with certainty. So, statement 1 is NOT SUFFICIENT Statement 2: -1 < y < 5 There are several values of x and y that ...”
May 21, 2018
Brent@GMATPrepNow posted a new topic called Is 2 < xy < 20? in the Data Sufficiency forum
“Is 2 < xy < 20? (1) -2 < x < 4 (2) -1 < y < 5 Answer: E Difficulty level: 450 - 500 Source: www.gmatprepnow.com”
May 20, 2018
Brent@GMATPrepNow posted a new topic called On Monday, Karen had S dollars in her savings account in the Problem Solving forum
“On Monday, Karen had S dollars in her savings account and C dollars in her checking account. On Tuesday, Karen transferred half of the money in her savings account to her checking account. On Wednesday, Karen transferred 20% of the money in her checking account to her savings account, at which point ...”
May 20, 2018
Brent@GMATPrepNow posted a reply to m and n are positive integers. If mn + 2m + n + 1 is even, in the Problem Solving forum
“Here''s a different solution: Since m and n can each be either even or odd, there are 4 possible cases to consider: case a) m is EVEN and n is EVEN case b) m is ODD and n is EVEN case c) m is EVEN and n is ODD case d) m is ODD and n is ODD Now let''s test each case as we examine mn + 2m + ...”
May 19, 2018
Brent@GMATPrepNow posted a reply to m and n are positive integers. If mn + 2m + n + 1 is even, in the Problem Solving forum
“There are several ways to approach this question. Here''s one approach: First recognize that mn + 2m + n + 1 is ALMOST factorable. If the expression were mn + 2m + n + 2, then we COULD factor it. Next, recognize that, if mn + 2m + n + 1 is even, then mn + 2m + n + 2 must be ODD Now recognize ...”
May 19, 2018
Brent@GMATPrepNow posted a reply to OG12: An arithmetic sequence in the Problem Solving forum
“Basically, an arithmetic sequence is a sequence in which each term can be calculated by adding some constant, k, to the preceding term. Some examples: 6, 8, 10, 12, 14,... (adding 2 to each term to get the next term) -1, 6, 13, 20, 27,... (adding 7 to each term to get the next term) 10, 7, ...”
May 18, 2018
Brent@GMATPrepNow posted a reply to Jerry travels 8 miles at an average speed of 40 miles per in the Problem Solving forum
“Your solution is perfect! That said, another approach is to focus on the 2nd part of the trip. In the first part of the trip, Jerry travels 8 miles at an average speed of 40 miles per hour In the 2nd part of the trip, Jerry stops for 10 minutes, and then travels another 20 miles at an ...”
May 18, 2018
Brent@GMATPrepNow posted a reply to m, n and k are positive integers. If the product in the Data Sufficiency forum
“Target question: Is k odd? Given: The product mn is odd If the product mn is odd, when we know that m is ODD and n is ODD Statement 1: mn + n + k is odd In other words: (ODD)(ODD) + ODD + k is odd Simplify: ODD + ODD + k is odd Simplify more: EVEN + k is odd This means k must be ...”
May 18, 2018
Brent@GMATPrepNow posted a reply to To offset miscellaneous costs, a dealership decides to in the Problem Solving forum
“Sorry, vinni.k, but I don''t understand what you are saying. Can you elaborate? Cheers, Brent”
May 18, 2018
Brent@GMATPrepNow posted a reply to How many sides does polygon P have? (1) All sides of P have in the Data Sufficiency forum
“Target question: How many sides does polygon P have? Statement 1: All sides of P have equal lengths. There are infinitely many polygons that satisfy statement 1. Here are two: Case a: Polygon P is an equilateral triangle. In this case, the answer to the target question is polygon P has 3 ...”
May 18, 2018
Brent@GMATPrepNow posted a reply to If a number between 10 and 50 (inclusive) at random. in the Problem Solving forum
“I think that listing (while looking for a pattern) and counting is the best/fastest approach here. Let''s list all of the numbers (from 10 to 50 inclusive) such that the tens digit is greater than one digit Numbers with tens digit 1: 10 Numbers with tens digit 2: 20, 21 Numbers with tens ...”
May 18, 2018
Brent@GMATPrepNow posted a reply to To offset miscellaneous costs, a dealership decides to in the Problem Solving forum
“I''m not entirely sure this question is ambiguous. I read it as: one of the motorcycles (we''ll name it Clark) gets a 7% price increase PLUS an additional increase of $350 These changes are equivalent to a 9% price increase (for Clark) As we can see, it doesn''t make a difference whether each ...” May 17, 2018 Brent@GMATPrepNow posted a new topic called m and n are positive integers. If mn + 2m + n + 1 is even, in the Problem Solving forum “m and n are positive integers. If mn + 2m + n + 1 is even, which of the following MUST be true? i) (2n + m)² is even ii) n² + 2n – 11 is even iii) m² – 2mn + n² is odd A) ii only B) ii and iii only C) i and ii only D) i and iii only E) i, ii and iii Answer: E Difficulty ...” May 17, 2018 Brent@GMATPrepNow posted a reply to Is x < 0? (1) -2x > 0 (2) x^3 < 0 in the Data Sufficiency forum “Target question: Is x < 0? Statement 1: -2x > 0 Divide both sides by -2 to get: x < 0 So, the answer to the target question is YES, x < 0 Since we can answer the target question with certainty, statement 1 is SUFFICIENT Statement 2: x^3 < 0 Since x^2 must be POSITIVE ...” May 17, 2018 Brent@GMATPrepNow posted a reply to An investment compounds annually at an interest rate in the Problem Solving forum “We can use fractions to solve this question. Each year, the investment increases 34.1% This is very close to an increase of 1/3 (33.33%) So, if the investment increases by 1/3 each year, then each year, we can find the value of the investment by multiplying last year''s value by 4/3 (this ...” May 17, 2018 Brent@GMATPrepNow posted a new topic called m, n and k are positive integers. If the product in the Data Sufficiency forum “m, n and k are positive integers. If the product mn is odd, is k odd? (1) nm + n + k is odd (2) n² – kn – 6k² is even Answer: D Difficulty level: 600 - 650 Source: www.gmatprepnow.com” May 16, 2018 Brent@GMATPrepNow posted a reply to basic algebra in the Problem Solving forum “What is the source of these questions you''ve recently posted? They don''t seem GMAT--worthy. Cheers, Brent” May 16, 2018 Brent@GMATPrepNow posted a reply to Roger's edge fund is taking x dollars and investing in bonds in the Problem Solving forum “Roger''s hedge fund is taking x dollars and investing in bonds that yield r percent in simple interest. The amount of interest earned over 2 years is$1000. So, the original investment of x dollars results in $500 interest EACH YEAR In terms of x, what dollar amount invested will yield$4000 ...”
May 16, 2018
May 16, 2018
Brent@GMATPrepNow posted a reply to If (-20) + (-19) + (-18) + (-17) + . . . in the Problem Solving forum
“First notice that (-20) + (-19) + (-18) + (-17) + . . . + 17 + 18 + 19 + 20 = 0 So, we have: (-20) + (-19) + (-18) + (-17) + . . . + 17 + 18 + 19 + 20 + 21 + 22 + ? + ? + ... + (-2x - 4) = 90 Simplify to get: -0 + 21 + 22 + ? + ? + ... + (-2x - 4) = 90 We can see that we won''t need to add ...”
May 16, 2018
Brent@GMATPrepNow posted a reply to when n divided by 3, the remainder is 2. in the Problem Solving forum
“IMPORTANT: Many integer property questions can be found quickly by identifying values that satisfy the given information. ---------ASIDE------------------ 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, ...”
May 16, 2018
Brent@GMATPrepNow posted a reply to Which of the following numbers is the biggest in the Problem Solving forum
“Since we''re dealing with NEGATIVE numbers, the greatest number will be the one with the smallest MAGNITUDE For example, 2 < 3, so we know that -2 is greater than -3 Likewise, 11 < 12, so we know that -11 is greater than -12 Of the values 6/7, 7/8, 9/10, 12/13 and 34/35, the fraction ...”
May 16, 2018
Brent@GMATPrepNow posted a reply to Each vote in a certain election went to one of the two candi in the Data Sufficiency forum
“We can use the Double Matrix Method here to help us arrange our information. The Double Matrix 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 voters, and the two characteristics are: - male or ...”
May 16, 2018
Brent@GMATPrepNow posted a reply to Mark can paint twice as fast as Joe. If Mark starts to paint in the Problem Solving forum
“Mark can paint twice as fast as Joe. So, for every 1 foot of wall that Joe paints, Mark can paint 2 feet of wall. In other words, for every 3 feet of wall that the two man paint TOGETHER, Joe moves 1 foot and Mark moves 2 feet. Generally speaking, for every x feet of wall that the two man ...”
May 15, 2018
Brent@GMATPrepNow posted a reply to A boat traveled a total of 600 miles in two days. If the in the Problem Solving forum
“Let F = number of miles traveled on first day Let S = number of miles traveled on second day A boat traveled a total of 600 miles in two days. So, we can write: F + S = 600 The distance it traveled on the first day was 150 miles less than twice the distance it traveled on the second day ...”
May 15, 2018
Brent@GMATPrepNow posted a new topic called If a = 100, what is the value of c? in the Problem Solving forum
“https://i.imgur.com/DxjVcg8.png If a = 100, what is the value of c? (1) b = 30 (2) f = 50 Answer: D Source: www.gmatprepnow.com Difficulty level: 500-550”
May 15, 2018
Brent@GMATPrepNow posted a new topic called If (-20) + (-19) + (-18) + (-17) + . . . in the Problem Solving forum
“If (-20) + (-19) + (-18) + (-17) + . . . + (-2x - 4) = 90, what is the value of x? A) -24 B) -14 C) -10 D) 10 E) 14 Answer: B Source: www.gmatprepnow.com Difficulty level: 550-600”
May 15, 2018
Brent@GMATPrepNow posted a reply to ---P---Q---R---S---T--- In the figure above, what is the le in the Data Sufficiency forum
“Target question: What is the length of segment PQ? Statement 1: S is the midpoint of segment RT Since we are not given ANY actual measurements (i.e., lengths) whatsoever, there''s no way to determine the length of PQ Statement 1 is NOT SUFFICIENT Statement 2: Segment PT has length 10 and ...”
May 15, 2018
Brent@GMATPrepNow posted a reply to w, x, y and z are positive integers. When w is divided by x, in the Data Sufficiency forum
“Target question: What is the value of z? Given: w, x, y and z are positive integers. When w is divided by x, the quotient is y, and the remainder is z. Statement 1: x³ - 3x² + 2x = 0 Let''s solve this equation for x. Factor to get: x(x² - 3x + 2) = 0 Factor the quadratic to get: ...”
May 15, 2018
Brent@GMATPrepNow posted a reply to Working alone, Manuel finishes cleaning half the house in in the Problem Solving forum
“Another option for many work questions is to assign a nice value to the given job. Here, a nice value will be one that works well with the given numbers (6 hours, 1/2 the time, 1/3 of the time) So, have about 36. Let''s say the entire job of cleaning the house consists of cleaning 36 rooms. ...”
May 15, 2018
Brent@GMATPrepNow posted a reply to If k is negative, which of the following must also be negati 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: ...”
May 14, 2018
Brent@GMATPrepNow posted a reply to If 12x + 2y is 80% of 5y, what is the value of x/y ? in the Problem Solving forum
“Sionainn''s solution is perfect. It''s the same approach I''d use. However, here''s another approach (for kicks!) Let''s try to find some values for x and y that satisfy the given information: 12x + 2y is 80% of 5y Let''s first let y = 20, and then figure out what value of x is needed. We ...”
May 14, 2018
Brent@GMATPrepNow posted a reply to Last year Jenny was 5 feet tall, and this year she is in the Problem Solving forum
“Old height: 5 feet = 60 inches New height: 5 feet 6 inches = 66 inches Percent increase = (100)(new - old)/old = (100)(66 - 60)/60 = (100)(6)/60 = 600/60 = 10% Answer: B Cheers, Brent”
May 14, 2018
Brent@GMATPrepNow posted a reply to If a = 4b, what percent of 2a is 2b? in the Problem Solving forum
“I would have used the same approach that Mitch used. However, here''s an algebraic approach: If a = 4b, then 2a = 8b What percent of 2a is 2b? We can rewrite as: 2b/2a = what percent? Or, we can write: 2b/8b = what percent? Simplify: 1/4 = what percent? Since 1/4 = 25%, the correct ...”
May 14, 2018
Brent@GMATPrepNow posted a reply to If x is a positive integer, what is the least common in the Data Sufficiency forum
“Another approach: Target question: What is the LCM of x, 6 and 9? ASIDE: The LCM tells us about the prime factors that numbers have in common. For example: The LCM of 20 and 12 is 60 60 = (2)(2)(3)(5). So, the prime factorization of 60 has two 2''s, one 3, and one 5. Now examine the ...”
May 14, 2018
Brent@GMATPrepNow posted a reply to If x is a positive integer, what is the least common in the Data Sufficiency forum
“Target question: What is the LCM of x, 6 and 9? I''ll show you two different approaches. This first approach uses requires us to be able to think of pairs of values that have given LCM''s. This is a useful skill to have on the GMAT. Statement 1: The least common multiple of x and 6 is 30. ...”
May 14, 2018
Brent@GMATPrepNow posted a reply to A car traveled 60 mph from Belnap to Lincoln and 50 mph from in the Problem Solving forum
“That''s a perfectly valid approach. Here''s one slight modification: Once we know that the total time = 330/60 + 330/50, we might also see what happens when we find a common denominator BEFORE adding the parts. So, total time = 330/60 + 330/50 = (5)330/300 + (6)(330)/300 = (11)(330)/300 ...”
May 14, 2018
Brent@GMATPrepNow posted a reply to Finding the Number of Factors | Short Video in the GMAT Math forum
“Good post. Here''s a similar video: https://www.youtube.com/watch?v=lVZ9GXd6ZBE It also covers WHY the formula (for finding the number of factors) works. Cheers, Brent”
May 13, 2018
Brent@GMATPrepNow posted a new topic called If 12x + 2y is 80% of 5y, what is the value of x/y ? in the Problem Solving forum
“If 12x + 2y is 80% of 5y, what is the value of x/y ? A) 1/6 B) 1/4 C) 2/5 D) 1/2 E) 5/8 Answer: A Source: www.gmatprepnow.com Difficulty level: 550-600”
May 13, 2018
Brent@GMATPrepNow posted a new topic called w, x, y and z are positive integers. When w is divided by x, in the Data Sufficiency forum
“w, x, y and z are positive integers. When w is divided by x, the quotient is y, and the remainder is z. What is the value of z? 1) x³ - 3x² + 2x = 0 2) The least common multiple of w and x is 30. Answer: A Source: www.gmatprepnow.com Difficulty level: 600-650”
May 13, 2018
Brent@GMATPrepNow posted a reply to Is x + y > 6? in the Data Sufficiency forum
“Target question: Is x + y > 6? Statement 1: x + 2y > 8 Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 10 and y = 10. In this case, x + y = 10 + 10 = 20, which is greater than 6. So, the answer to the target question is ...”
May 12, 2018
Brent@GMATPrepNow posted a reply to If x > 0, is x^2 < x? in the Data Sufficiency forum
“Here''s another approach: Target question: Is x² ＜ x ? This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: Given: x > 0 Since we''re told that x is POSITIVE, we can safely take x² < x and divide ...”
May 12, 2018
Brent@GMATPrepNow posted a reply to If x > 0, is x^2 < x? in the Data Sufficiency forum
“Target question: Is x² < x? Statement 1: 0.1 < x < 0.4 A useful property says: If 0 < x < 1, then x² < x Since statement 1 basically tells that 0 < x < 1, we can be certain that x² < x Since we can answer the target question with certainty, statement 1 is ...”
May 12, 2018
Brent@GMATPrepNow posted a reply to 3-3*6+2= in the Problem Solving forum
“We must follow the order of operations (aka BEDMAS or PEMDAS) Given: 3 - 3 x 6 + 2 Must must perform all divisions and multiplications first. So, 3 - 3 x 6 + 2 = 3 - 18+ 2 Next, when given the options of subtraction and addition, we perform the operations from left to right So, we get: 3 - ...”
May 12, 2018
Brent@GMATPrepNow posted a reply to If X and Y are consecutive integers (Y>X), which of the in the Problem Solving forum
“If X and Y are consecutive integers, then one number must be EVEN and the other number must be ODD. If one number is ODD and one number is EVEN, then their product must be EVEN So, statement 1 (The product XY is an even number) is ALWAYS TRUE In other words, statement 1 can never be false ...”
May 12, 2018
Brent@GMATPrepNow posted a reply to Is x = 3? in the Data Sufficiency forum
“What''s the source of this question? On the GMAT, the statements will never contradict each other. In the above question, statement 1 tells us that x definitely equals 3, and statement 2 tells us that x definitely does NOT equal 3 More on this here: ...”
May 11, 2018
Brent@GMATPrepNow posted a reply to $\frac{19^2+19}{20}=$ in the Problem Solving forum
“Notice that we can factor 19 from the numerator. (19² + 19)/20 = (19)(19 + 1)/20 = (19)(20)/20 = 19 Answer: C Cheers, Brent”
May 11, 2018
Brent@GMATPrepNow posted a reply to How many factors does 36^2 have? 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 = ...”
May 11, 2018
Brent@GMATPrepNow posted a reply to If y + 40x + 2 = 0, what is the in the Data Sufficiency forum
“Target question: What is the value of xy? Given: y + 40x + 2 = 0 Rearrange to get: 40x + y = -2 IMPORTANT: We are given one linear equation. If we given a different linear equation, then we can be certain to solve the system of equations for x and y, which means we can determine the value ...”
May 11, 2018
Brent@GMATPrepNow posted a reply to The perimeter of a rectangular garden is 80 feet, and the in the Problem Solving forum
“Let W = the width of the rectangle Let L = the length of the rectangle The perimeter of a rectangular garden is 80 feet We can write: W + W + L + L = 80 Simplify to get: 2W + 2L = 80 Divide both sides by 2 to get: W + L = 40 The area of the garden is 391 square feet Area = ...”
May 11, 2018
Brent@GMATPrepNow posted a reply to A parking lot charges a flat rate of X dollars for any in the Problem Solving forum
“2 hours: cost = x dollars 3 hours: cost = x + x/6 dollars 4 hours: cost = x + x/6 + x/6 dollars 5 hours: cost = x + x/6 + x/6 + x/6 dollars 5.25 hours: cost = x + x/6 + x/6 + x/6 + x/6 dollars We must now simplify: x + x/6 + x/6 + x/6 + x/6 dollars Rewrite with common denominator: 6x/6 + ...”
May 11, 2018
beatthegmat posted a new topic called Prepping for the GRE When English is Not Your First Language in the GMAT Strategy forum
“English is a complex language. Ask around and you’ll hear that even native speakers can find it complicated and sometimes confusing. This can make the GRE® General Test particularly challenging when English is not your first language. With adequate practice, however, you can be sure to feel ...”
May 10, 2018
Brent@GMATPrepNow posted a reply to The system of equations above has how many solutions? in the Problem Solving forum
“Another approach is to begin solving the system (using the elimination method) and see what happens. Given: x - y = 3 2x = 2y + 6 Take bottom equation and divide both sides by 2 to get: x - y = 3 x = y + 3 Take bottom equation and subtract y from both sides to get: x - y = 3 x - y ...”
May 10, 2018
Brent@GMATPrepNow posted a reply to The system of equations above has how many solutions? in the Problem Solving forum
“Given: x - y = 3 2x = 2y + 6 Take 2x = 2y + 6 and divide both sides by 2 to get an EQUIVALENT equation x = y + 3 Now subtract y from both sides to get: to get another EQUIVALENT equation x - y = 3 Since this equation (x - y = 3) is identical to the other equation x - y = 3, we can be certain ...”
May 10, 2018
Brent@GMATPrepNow posted a reply to Three friends rented a car for a week and divided the cost e in the Problem Solving forum
“Let''s start with a word equation: (cost per person with 4 friends) = (cost per person with 3 friends) - $15 Let T = the total cost of renting the car So, cost per person with 4 friends = T/4 And cost per person with 3 friends = T/3 We can now take our word equation and fill in the missing ...” May 10, 2018 Brent@GMATPrepNow posted a reply to C/D = 9.75 when dividing positive integer C by positive in the Problem Solving forum “IMPORTANT: There are infinitely many pairs of values of C and D that satisfy the condition that C/D = 9.75 For example, 975/100 = 9.75. In this case, C = 975 and D = 100 Likewise, 195/20 = 9.75. In this case, C = 195 and D = 20 Also, 390/40 = 9.75. In this case, C = 390 and D = 40 And 39/4 = ...” May 9, 2018 Brent@GMATPrepNow posted a reply to A salesperson for an automobile dealer earns an annual salar in the Problem Solving forum “Total earnings = (base salary) + (commission) base salary =$25,000 commission = 10% of total sales OVER $100,000 = 10% of (x -$100,000) = 0.1(x - $100,000) So, total earnings =$25,000 + 0.1(x - $100,000) Answer: E Cheers, Brent” May 9, 2018 Brent@GMATPrepNow posted a reply to When a=x+(1/x) and b=x-(1/x), what is a^2 – b^2? in the Problem Solving forum “Given: a = x + 1/x and b = x - 1/x Our goal is to find the value of a² - b² To do so, it''s useful to recognize that the expression a² - b² is a difference of squares, which means we can rewrite it. When we do this, we get: a² - b² = (a + b)(a - b) Now replace a and b with their ...” May 9, 2018 Brent@GMATPrepNow posted a reply to If snow accumulation increased at a constant rate of 30 mill in the Problem Solving forum “Let''s keep listing EQUIVALENT RATES until we get to 1 millimeter 30 millimeters per hour = 30 millimeters per 60 minutes = 30 millimeters per 3600 SECONDS = 3 millimeters per 360 SECONDS = 1 millimeter per 120 SECONDS Answer: E Cheers, Brent” May 9, 2018 Brent@GMATPrepNow posted a reply to In the Land of OZ only one or two-letter words are used. in the Problem Solving forum “6 6 as its units digit ] Likewise 65² = (65)(65) = ----5 So, we get: The number of words lost = 6 + ---6] - 5 + ----5] = (------2) - (----0) = ------2 Since only answer choice E has a units digit of 2, the correct answer must be E Cheers, Brent” May 8, 2018 Brent@GMATPrepNow posted a reply to If a,b,x, and y are positive integers, is a^-x > b^-y? ( in the Data Sufficiency forum “Target question: Is a^(-x) > b^(-y)? This is a great candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: First recognize the following: a^(-x) = 1/(a^x) and b^(-y) = 1/(b^y) So, we can ask Is 1/(a^x) > 1/(b^y)? Also, ...” May 8, 2018 Brent@GMATPrepNow posted a reply to Two integers will be randomly selected from sets A and B, in the Problem Solving forum “Take the task of creating products and break it into stages. Stage 1: Select a number from set A There are 5 numbers to choose from, so we can complete stage 1 in 5 ways Stage 2: Select a number from set B There are 4 numbers to choose from, so we can complete stage 2 in 4 ways By the ...” May 8, 2018 Brent@GMATPrepNow posted a reply to For an integer n greater than 1, n* denotes the product of in the Problem Solving forum “7* = 7! = (7)(6)(5)(4)(3)(2)(1) So, 7* + 2 = (7)(6)(5)(4)(3)(2)(1) + 2 = 22 So, 7* + 2 is NOT a prime number 7* + 3 = (7)(6)(5)(4)(3)(2)(1) + 3 = 33 So, 7* + 3 is NOT a prime number 7* + 4 = (7)(6)(5)(4)(3)(2)(1) + 4 = 44 So, 7* + 4 is NOT a prime number . . . . 7* + 7 = ...” May 8, 2018 beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum “Hi fsb_20 Your account has been deleted.” May 7, 2018 Brent@GMATPrepNow posted a reply to Is x > y? in the Data Sufficiency forum “Target question: Is x > y? Statement 1: 6x > 5y 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. Notice that 6x > 5y becomes 6 > -5, which is true. In this ...” May 7, 2018 Brent@GMATPrepNow posted a reply to If 5m=25^{2n}, what is the value of m, in terms of n? in the Problem Solving forum “Given: 5m = 25^(2n) Rewrite 25 as 5² to get: 5m = (5²)^(2n) Apply power of a power law to get: 5m = 5^(4n) Divide both sides by 5 to get: m = [5^(4n)]/5 Since 5 = 5¹, we get: : m = [5^(4n)]/(5¹) Apply quotient law to get: m = 5^(4n - 1) Answer: C Cheers, Brent” May 7, 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 In other words, x = 4 Since we have no information about y, statement 1 is NOT SUFFICIENT Statement 2: (x - 3)(y - 7) = 0 This tells us that EITHER x = 3 OR y = 7 So, y COULD equal 7, or y might not equal 7 For example, consider ...” May 6, 2018 Brent@GMATPrepNow posted a reply to W, X, Y and Z each represent a different number in the Problem Solving forum “I believe Mitch has provided the best/fastest approach. Cheers, Brent” May 6, 2018 Brent@GMATPrepNow posted a reply to If a car went the first third of the distance at 80 kmh in the Problem Solving forum “Here''s an algebraic approach: Let d = 1/3 of the total distance traveled So, the car traveled d km at 80 kmh, then the car traveled d km at 24 kmh, and then d km at 48 kmh Average speed = (total distance traveled)/(total travel time) Total distance traveled = d + d + d = 3d time = ...” May 6, 2018 Brent@GMATPrepNow posted a reply to Sheila works 8 hours per day on Monday, Wednesday and Friday in the Problem Solving forum “We can avoid long division if we make an important observation. Let''s take it from the point were you got: earning per hour =$324/36 You might notice that $360/36 =$10 Also notice that $324 =$360 - $36 So,$324/36 = ( $360 -$36)/36 = $360/36 -$36/36 = 10 - 1 = 9 = Answer choice C ...”
May 6, 2018
Brent@GMATPrepNow posted a reply to In a certain school, the ratio of boys to girls is in the Problem Solving forum
“Another approach: Let B = # of boys Let G = # of girls The ratio of boys to girls is 5 to 13. We can write: B/G = 5/13 Cross multiply to get: 13B = 5G There are 72 more girls than boys We can write G = B + 72 Alternatively, we can write: G - 72 = B We now have two equations: 13B = ...”
May 6, 2018
Brent@GMATPrepNow posted a reply to In a certain school, the ratio of boys to girls is in the Problem Solving forum
“One approach: GIVEN: the ratio of boys to girls is 5 to 13 There are several possible cases that meet this condition: - there are 5 boys and 13 girls - there are 10 boys and 26 girls - there are 15 boys and 39 girls . . . NOTE: We''re also told that there are 72 more girls than ...”
May 6, 2018
Brent@GMATPrepNow posted a reply to If $936 are divided bettween worker A and B in the ratio in the Problem Solving forum “Your solution is perfect. I''d just like to point out how get convert 7/12 to a percent. As you''ve shown, to convert a fraction to a percent, we convert to a decimal and multiply it by 100 So, (7/12)(100) = 700/12 = 350/6 = 175/3 = 58 1/3 = 58 + 0.333333.... = 58.333333....% As you ...” May 5, 2018 Brent@GMATPrepNow posted a reply to A discount of 20 percent on an order of goods in the Problem Solving forum “Let''s start with a nice number Let$100 be the ORIGINAL price. So, a 20% discount on $100 =$20, which means the discounted price = $100 -$20 = $80 Next, a 20% discount on$80 = $16, which means the NEW discounted price =$80- $16 =$64 So, if the ORIGINAL price = $100, the DOUBLE ...” May 4, 2018 Brent@GMATPrepNow posted a reply to In a room filled with 7 people, 4 people phave exactly 1 in the Problem Solving forum “First we need to recognize that the given information tells us that the 7 people consist of: - a sibling trio - a sibling pair - and another sibling pair Using counting techniques: For this question, it''s easier to find the complement. So P(not siblings) = 1 - P(they are siblings) ...” May 4, 2018 Brent@GMATPrepNow posted a reply to If c and f are integers, is zc > zf? in the Data Sufficiency forum “Target question: Is zc > zf? Statement 1: z³c > z³f This tells us that z ≠ 0 It also means that z² > 0 Since z² is POSITIVE, we can safely divide both sides of the statement 2 inequality by z² to get: xc > zf PERFECT!! The answer to the target question is YES, xc IS ...” May 4, 2018 Brent@GMATPrepNow posted a reply to If x and y are positive integers and x>y, is x/y an integ in the Data Sufficiency forum “Target question: Is x/y an integer? Given: x and y are positive integers and x>y Statement 1: x is a multiple of 10 No information about y. Statement 1 is NOT SUFFICIENT Statement 2: y is a multiple of 2 No information about x. Statement 2 is NOT SUFFICIENT Statements 1 ...” May 4, 2018 Brent@GMATPrepNow posted a reply to If x is the sum of the first 10 positive multiples of 3 and in the Problem Solving forum “x is the sum of the first 10 positive multiples of 3 So, x = 3 + 6 + 9 + 12 + .... Factor out the 3 to get: x = 3(1 + 2 + 3 + 4 + . . . . + 9 + 10) y is the sum of the first 10 positive multiples of 2 So, y = 2 + 4 +6 + 8 + 10 + ... Factor out the 2 to get: y = 2(1 + 2 + 3 + 4 + . . . . + 9 + ...” May 4, 2018 Brent@GMATPrepNow posted a reply to Five percent of a certain grass seed is timothy. If the in the Problem Solving forum “We have 240 pounds of the seed mixture, and 5% of the mixture is timothy. So: TOTAL weight of timothy = 5% of 240 pounds = 12 pounds So, we there are 12 pounds of timothy in the mixture, and 2 pounds of timothy is needed for 1 acre This means 4 pounds of timothy is needed for 2 acres And 6 ...” May 3, 2018 Brent@GMATPrepNow posted a reply to Some fourth graders are choosing foursquare teams at in the Problem Solving forum “This is a somewhat ambiguous question since it''s hard to tell whether each team member''s position matters. For example, if the question were rephrased to ask how many 9-person baseball teams can be created from 9 people, we might say the correct answer is 1. However, if we consider the ...” May 3, 2018 Brent@GMATPrepNow posted a reply to What is the largest integer if the sum of three consecutive in the Problem Solving forum “Let x = the smallest value So, x + 2 = the middle value And x + 4 = the biggest value The sum is 318 So, we can write x + (x+2) + (x+4) = 318 Simplify: 3x + 6 = 318 Subtract 6 from both sides to get: 3x = 312 Solve: x = 104 So, the SMALLEST value = 104 This means 106 is the MIDDLE value ...” May 3, 2018 Brent@GMATPrepNow posted a reply to What is the units digit of 36^y? (A) y is a positive in the Data Sufficiency forum “Target question: What is the units digit of 36^y? Statement 1: y is a positive integer So, y = 1 or 2 or 3 or 4 or 5 or... Notice that 36^1 = 36 (units digit = 6) Notice that 36^2 = ---6 (units digit = 6) Notice that 36^3 = ---6 (units digit = 6) Notice that 36^4 = ---6 (units digit = 6) ...” May 3, 2018 Brent@GMATPrepNow posted a reply to A group of 8 friends want to play doubles tennis. in the Problem Solving forum “Let the 8 people be: A, B, C, D, E, F, G, and H Take the task of creating the teams and break it into stages. Stage 1: Select a partner for person A There are 7 people to choose from, so we can complete stage 1 in 7 ways ASIDE: There are now 6 people remaining. Each time we pair up two ...” May 3, 2018 Brent@GMATPrepNow posted a reply to George tried to compute the mean average of his 8 test in the Problem Solving forum “Let T = the sum of all of George''s test scores. George divided the sum of his test scores by 7 to get 96. So we get: T/7 = 96 Multiply both sides by 7 to get: T = (96)(7) To get the ACTUAL average, George SHOULD have divided the sum of his test scores by 8 So, ACTUAL average = T/8 = ...” May 3, 2018 Brent@GMATPrepNow posted a reply to For all positive integers m and n, the expression m X n in the Problem Solving forum “19∆9 = the remainder when (19+9) is divided by (19-9) = the remainder when 28 is divided by 10 = 8 So, (19∆9)∆2 = 8∆2 = the remainder when (8+2) is divided by (8-2) = the remainder when 10 is divided by 6 = 4 ------------------------------------------------------------- 9∆2 = the ...” May 3, 2018 Brent@GMATPrepNow posted a reply to If x is a positive integer, is x/30 a terminating decimal? in the Data Sufficiency forum “Target question: Is x/30 a terminating decimal? This is a good candidate for rephrasing the target question. -------------ASIDE------------------ Let''s say that x = a/b where the fraction a/b is written in simplest terms. There''s a nice rule that says something like, If a/b results in a ...” May 3, 2018 Brent@GMATPrepNow posted a reply to How many odd three-digit integers greater than 800 are there in the Problem Solving forum “Here''s a similar one to practice with: http://www.beatthegmat.com/counting-a-3-digit-number-greater-than-700-t288550.html Cheers, Brent” May 3, 2018 Brent@GMATPrepNow posted a reply to How many multiples of 4 lie between 4^4 and 4^5, inclusive? in the Problem Solving forum “Mitch used the same approach I would have used, so here''s a different solution. 4^4 = (4³)(4) = (64)(4) 4^5 = (4⁴)(4) = (256)(4) So, we want the multiples of 4 from (64)(4) to (256)(4) inclusive. The multiples of 4 are: (64)(4), (65)(4), (66)(4), (67)(4), (68)(4), . . . (256)(4) A ...” May 3, 2018 Brent@GMATPrepNow posted a reply to If 25(5^x) = 1 then x= in the Problem Solving forum “Given: (25)(5^x) = 1 Divide both sides by 25 to get: 5^x = 1/25 (aka 1/5²) Rewrite 1/25 as 5^(-2) to get: 5^x = 5^(-2) So, x = -2 Answer: A Cheers, Brent” May 2, 2018 Brent@GMATPrepNow posted a reply to The distance between Alice’s house and Bob's is 120 miles. in the Problem Solving forum “The correct answer is showing up as B Upon re-reading the question, we can see that it''s somewhat ambiguous, because it doesn''t specify where Alice and Bob are when they begin their journeys (although I also assumed that Alice started at her own house and Bob started at his own house). If each ...” May 2, 2018 Brent@GMATPrepNow posted a reply to Larry can build a model car in 3 hours, Moe can build the in the Problem Solving forum “Your approach (of assigning a nice value to the job) is perfect. Here''s another approach.... RULE: 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 ...” May 2, 2018 Brent@GMATPrepNow posted a reply to is p prime number in the Data Sufficiency forum “Target question: Is p a prime number? Given: p is an integer greater than 1 Statement 1: p is a factor of 13 The only positive factors of 13 are 1 and 13 Since we''re told that p is greater than 1, we can conclude that p MUST equal 13 So, the answer to the target question is YES, p IS ...” May 2, 2018 Brent@GMATPrepNow posted a reply to If x and y are positive integers, what is the remainder when in the Data Sufficiency forum “Target question: What is the remainder when x+y is divided by 2? Statement 1: xy is divisible by 4 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 = 4. Here xy = (2)(4) = 8, and 8 is divisible by 4. In this case, x +y ...” May 2, 2018 Brent@GMATPrepNow posted a reply to When a positive integer n is divided by 29, what is the in the Data Sufficiency forum “Target question: What is the remainder when n is divided by 29? Statement 1: n-5 is divisible by 29 So, we can say that: n-5 = 29k for some integer k Add 5 to both sides of the equation to get: n = 29k + 5 We can see that n is 5 greater than some multiple of 29 So, if we divide n by 29, ...” May 1, 2018 Brent@GMATPrepNow posted a reply to In the figure below, the area of triangle PQR is 40. in the Problem Solving forum “We can see that: (area of ∆PQS) + (area of ∆QRS) = (area of ∆PQR) So, we can write: (area of ∆PQS) + (area of ∆QRS) = 40 We also have enough information to determine the area of ∆PQS Area of triangle = (base)(height)/2 So, area of ∆PQS = (5)(6)/2 = 30/2 = 15 Now add this ...” May 1, 2018 Brent@GMATPrepNow posted a reply to Four values from a data set of 5 elements are 10, 10, 11, an in the Data Sufficiency forum “Let''s say that x = the missing data value Target question: What is the value of x? Given: The other 4 values are 10, 10, 11 and 11 Statement 1: The range of the data set is 2 So, (the biggest value) - (the smallest value) = 2 The problem here is that x COULD be the smallest value, ...” May 1, 2018 Brent@GMATPrepNow posted a reply to Working alone at its constant rate, machine A can complete a in the Problem Solving forum “Working alone at its constant rate, machine A can complete a job in 24 hours. The work rate of machine B is 1/2 that of machine A. So, it must take Machine B 48 hours to complete the job. Now let''s assign a nice value to the job. That is, we''ll assign a value that works well with 24 hours ...” May 1, 2018 Brent@GMATPrepNow posted a reply to A rectangular wall is completely filled with square tiles of in the Problem Solving forum “. . . and no tiles with a common side are the same color To meet this condition, it MUST be the case that the yellow and orange squares are arranged in a checkerboard pattern. In such a checkerboard pattern, the colors alternate yellow, orange, yellow, orange, yellow, orange etc This means half ...” April 30, 2018 Brent@GMATPrepNow posted a reply to In an electric circuit, two resistors with resistances x and in the Problem Solving forum “The reciprocal of r is equal to the sum of the reciprocals of x and y So, 1/r = 1/x + 1/y We must solve this equation for r. Take: 1/r = 1/x + 1/y Rewrite the right side with a COMMON DENOMINATOR of xy: 1/r = y/xy + x/xy Combine the two terms to get: 1/r = (y + x)/xy Since we have two ...” April 30, 2018 Brent@GMATPrepNow posted a reply to The minimum of the integers x, y, and z is 10 and their aver in the Problem Solving forum “Key concept: If we know the sum of a set of numbers, and we want to MAXIMIZE the biggest number in the set, we must MINIMIZE all of the other numbers. GIVEN: Average of x, y, and z is 11 So, (x + y + z)/3 = 33 This means x + y + z = 33 Great! We know the sum of the values. In order to ...” April 30, 2018 Brent@GMATPrepNow posted a reply to During one day, a door-to-door salesman sold three fourths in the Problem Solving forum “If 3/4 of the bricks were SOLD, then the remaining bricks (1/4 of the bricks) were NOT SOLD. If 150 = 1/4 of the bricks, then 450 = 3/4 of the bricks In other words, the salesman sold 450 bricks If 450 bricks were sold at$0.25, then the money collected = (450)($0.25) =$112.50 Answer: D ...”
April 30, 2018
Brent@GMATPrepNow posted a reply to If the profit on a product is 20 percent of its sales price, in the Problem Solving forum
“Choosing numbers that satisfy the given conditions (as others above have done) is the best/fastest approach. Here''s a (longer) algebraic approach. Let SALE price = x So, PROFIT = 20% of x = 0.2x COST PRICE = SALE PRICE - PROFIT = x - 0.2x = 0.8x What percent is the profit of the ...”
April 30, 2018
Brent@GMATPrepNow posted a reply to Double matrix method in the Data Sufficiency forum
“This question type (overlapping sets) is VERY COMMON on the GMAT, so be sure to master the Double Matrix Method. Here''s a video covering the strategy: Easy Problem Solving questions - http://www.beatthegmat.com/finance-majors-non-finance-majors-overlapping-set-question-t167425.html Medium ...”
April 30, 2018
Brent@GMATPrepNow posted a reply to Mud from a lake on an uninhabited wooded island in the Critical Reasoning forum
“PREMISE: Island lake contains toxic chemicals PREMISE: The chemicals were not dumped in the lake, and water from Lake Superior cannot reach the lake We want to find the most reasonable conclusion that follows from this information (A) The waters of the island lake are more severely polluted ...”
April 30, 2018
Brent@GMATPrepNow posted a reply to If a certain dog ate 1/5 of his food on a certain day in the Problem Solving forum
“Your approach is great. Another approach would be to choose some numbers that satisfy the given conditions. . . . a certain dog ate 1/5 of his food on a certain day So, let''s say the dog had 5 pounds of food available. If the dog ate 1/5 of its food, then it ate 1/5 of 5 pounds. So, the ...”
April 29, 2018
Brent@GMATPrepNow posted a reply to Is positive integer z greater than 275? in the Data Sufficiency forum
“Target question: Is positive integer z greater than 275? Statement 1: z is a multiple of 21 Let''s TEST some values. There are several values of z that satisfy statement 1. Here are two: Case a: z = 21, in which case, the answer to the target question is NO, z is NOT greater than 275 ...”
April 28, 2018
Brent@GMATPrepNow posted a reply to $If \, 8^{13}=2^z , then \, z=$ in the Problem Solving forum
“GIVEN: 8^13 = 2^z We want to rewrite our powers so that they have the SAME BASE Rewrite 8 as 2^3 to get: ( 2^3)^13 = 2^z Simplify left side to get: 2^39 = 2^z So, it must be the case that 39 = z Answer: E Cheers, Brent”
April 27, 2018
Brent@GMATPrepNow posted a reply to If x is a positive integer greater than 1, is 1/x in the Data Sufficiency forum
“Target question: Is 1/x a terminating decimal? This is a good candidate for rephrasing the target question. There''s a nice rule that says something like, If a/b results in a terminating decimal, then the denominator, b, MUST be the product of 2''s and 5''s only! So, for example, if b = 20, ...”
April 27, 2018
Brent@GMATPrepNow posted a reply to If the average of 2x and 4x is 12, then x in the Problem Solving forum
“Given: the average of 2x and 4x is 12 We can write: (2x + 4x)/2 = 12 Simplify: 6x/2 = 12 Simplify: 3x = 12 Solve: x = 4 Answer: D Cheers, Brent”
April 27, 2018
Brent@GMATPrepNow posted a reply to 1/2 of 0.2 percent equals in the Problem Solving forum
“Fraction, decimals and percents are all similar ways of expressing a quantity. For example: 19% = 19/100 = 0.19 123% = 123/100 = 1.23 2% = 2/100 = 0.02 So, 0.2% = 0.2/100 = 2/1000 = 0.002 So, 1/2 of 0.2 percent = 1/2 of 0.002 = 0.0001 Answer: D Cheers, Brent”
April 27, 2018
Brent@GMATPrepNow posted a reply to Is b an even integer? in the Data Sufficiency forum
“Target question: Is b an even integer? Statement 1: The product of b and integer c is even. Let''s TEST some values. There are several values of b and c that satisfy statement 1. Here are two: Case a: b = 2 and c = 3. Here, the product bc = (2)(3) = 6, which is even. In this case, b = 2, ...”
April 27, 2018
Brent@GMATPrepNow posted a reply to What is the perimeter of a regular polygon with in the Problem Solving forum
“Sum of ALL sides in an n-sided polygon = (n - 2)(180) degrees So, EACH ANGLE in a regular n-sided polygon = (n - 2)(180)/n degrees We''re told that EACH ANGLE is 144°, so we can write: (n - 2)(180)/n = 144 Multiply both sides by n to get: (n - 2)(180) = 144n Expand left side: 180n - 360 = ...”
April 27, 2018
Brent@GMATPrepNow posted a reply to Is median of a, b and c equal to their average (arithmetic m in the Data Sufficiency forum
“Target question: Is the median of a, b and c equal to their average (arithmetic mean)? Statement 1: a ≤ b ≤ c Let'' TEST some values. There are several values of a, b and C that satisfy statement 1. Here are two: Case a: a = 1, b = 1 and c = 1. The median = 1 = mean. In this case, the ...”
April 26, 2018
Brent@GMATPrepNow posted a reply to ACME’s manufacturing costs for sets of horseshoes include in the Problem Solving forum
“That''s a great solution. Here''s a slight twist: It COSTS $19.75 per set, and each set is SOLD for$52.50 So, the company makes approximately $33 per set ($52.50 - $19.75 ≈$33) The company sold 987 sets. So, the profit ≈ ($33)(1000) ≈$33,000 Keep in mind, that there''s also ...”
April 26, 2018
Brent@GMATPrepNow posted a reply to A certain box has 10 cards written integers from 1 to 10 in the Problem Solving forum
“As AAPL has shown, the average value of the ten cards is 5.5 So, we want to find P(sum of 2 cards is less than 5.5) We can use combinations to determine the umber of ways to select 2 of the 10 cards We can select 2 cards from 10 cards is 10C2 ways (= 45 ways) When we examine the answer ...”
April 25, 2018
Brent@GMATPrepNow posted a reply to What is the median of m, n and 5? in the Data Sufficiency forum
“Target question: What is the median of m, n and 5? Statement 1: m + n = 10 Let''s examine the ONLY TWO possible cases: m and n are equal and m and n are NOT equal Case a: m and n are equal. That is m = 5 and n = 5. In this case, the set = {5, 5, 5 }, in which case the answer to the target ...”
April 25, 2018
beatthegmat posted a new topic called 5 Terror-inducing, Success-busting, Career-ending Mistakes in the MBA Student Life forum
“Nobody is perfect. Bill Gates ignored the signs showing the importance of internet search. Richard Branson believed he could oust Coca-Cola and Pepsi with his meager Virgin Cola. Tim Cook launched Apple Maps before it was ready. Everyone makes mistakes, even those people who are largely regarded as ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to The population of City X doubles every 25 years in the Problem Solving forum
“Let''s make a table TIME | POPULATION Now: 20,000 25 years from now: 40,000 50 years from now: 80,000 75 years from now: 160,000 100 years from now: 320,000 125 years from now: 640,000 150 years from now: 1,280,000 So, it will take 150 years (aka 1.5 centuries) for the population to ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to helpp!! with trianglee in the Data Sufficiency forum
“Given: In triangle ABC, point X is the midpoint of side AC and point Y is the midpoint of side BC. If point R is the midpoint of line segment XC and if point S is the midpoint of line segment YC Let''s make a few observations before we do anything else. As others have pointed out before me, the ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to QR-162 in the Problem Solving forum
“Since OC = AC, ∆AOC is an isosceles triangle, which means ∠OAC is also x° https://s1.postimg.cc/568w34movv/image.png Since all 3 angles in ∆AOC must add to 180°, we can conclude that ∠OCA = (180-2x)° https://s1.postimg.cc/27wlzmeuu3/image.png Since angles on a LINE must add to ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to Alice and Bruce each bought a refrigerator, and the sum of in the Problem Solving forum
“We can also solve the question algebraically, using 1 variable or 2 variables. Here''s a solution with 1 variable: Given: Twice of what Alice paid was $75 more than what Bruce paid Let x = the amount Alice paid So, 2x - 75 = the amount Bruce paid Given: The sum of their purchases was ...” April 24, 2018 Brent@GMATPrepNow posted a reply to Alice and Bruce each bought a refrigerator, and the sum of in the Problem Solving forum “This question lends itself nicely to testing the answer choices We''ll start with answer choice C ($425), the middle value. If Alice paid $425, how much did Bruce pay? Given: twice of what Alice paid was$75 more than what Bruce paid Two times $425 =$850, so Bruce paid $775 (since$850 - ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to Set T consists of 82 consecutive odd integers. If the sum of in the Problem Solving forum
“Here''s another approach: 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 set T ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to Is a^5 divisible by 4? in the Data Sufficiency forum
“Target question: Is a^5 divisible by 4? Statement 1: a^5 – 8 is divisible by 4. In other words, a^5 – 8 is a MULTIPLE OF 4 So, we can say that: a^5 – 8 = 4k for some integer k Add 8 to both sides to get: a^5 = 4k + 8 (for some integer k) Factor the right side: a^5 = 4(k + 2) (for ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to P persons have decided to rent a van to tour while on in the Problem Solving forum
“P persons have decided to rent a van to tour while on holidays. The price of the van is x dollars and each person is to pay an equal share. ORIGINAL cost per person = (total cost)/(number of people paying) = x/P D persons cancel their trip thus failing to pay their share So, now the number of ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to How many possible 7-digit codes can be formed from the lette in the Problem Solving forum
“When we want to arrange a group of items in which some of the items are identical, we can use something called the MISSISSIPPI rule. It goes like this: If there are n objects where A of them are alike, another B of them are alike, another C of them are alike, and so on, then the total number of ...”
April 24, 2018
Brent@GMATPrepNow posted a reply to How many 5 digit numbers have at least o in the Problem Solving forum
“NOTE: We can solve this question without performing lengthy calculations (e.g., 9^5) # of 5-digit numbers with at least one zero digit = (TOTAL number of 5-digit numbers) - (number of 5-digit numbers without ANY 0''s) As Keith shows us above, we get: # of 5-digit numbers with at least one ...”
April 23, 2018
Brent@GMATPrepNow posted a reply to Set T consists of 100 consecutive odd integers. If k is an i in the Problem Solving forum
“One more approach: If Set T COULD look like this: { -99, -97 ..... -3, -1, 1, 3......97, 99 }, in which case the median = zero We can see that answer choices A, B, D and E could equal zero, so we can ELIMINATE them. Here''s what I mean: A) k² - k - 6 = (k + 2)(k - 3). So, answer choice ...”
April 23, 2018
Brent@GMATPrepNow posted a reply to If 3 < x < 7, Which of the following must be true? in the Problem Solving forum
“If x > 3, then x COULD equal 3.00000000000000000000000001, in which case x^2 will be less than 9.0001 This means we can ELIMINATE answer choices A, B, C and E By the process of elimination, we''re left with D Cheers, Brent”
April 23, 2018
Brent@GMATPrepNow posted a reply to Is the product of x and y a prime number? in the Data Sufficiency forum
“Target question: Is the product xy a prime number? Statement 1: x² = 1 This tells us that either x = 1 or x = -1, but it provides NO INFORMATION about y. Consider these two possible cases: Case a: x = 1 and y = 3. In this case, xy = (1)(3) = 3, which is prime. So, the answer to the ...”
April 23, 2018
Brent@GMATPrepNow posted a reply to Is s = r? in the Data Sufficiency forum
“Target question: Is s = r ? Statement 1: s² = r² This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of r and s that satisfy statement 1. Here are two: Case a: r = 1 and s = 1. Notice that s² = r² becomes (1)² = (1)², which satisfies the ...”
April 23, 2018
Brent@GMATPrepNow posted a reply to If n is an integer, is n - 1 even? in the Data Sufficiency forum
“Some important rules: 1. ODD +/- ODD = EVEN 2. ODD +/- EVEN = ODD 3. EVEN +/- ODD = ODD 4. EVEN +/- EVEN = EVEN Target question: Is n - 1 even? Statement 1: n - 2 is odd In other words, we can write n - 2 = ODD Add 1 to both sides to get: n - 2 + 1 = ODD + 1 Simplify: n - 1 = ODD + ...”
April 23, 2018
Brent@GMATPrepNow posted a reply to If x^2=x+1, then x^3=? in the Problem Solving forum
“GIVEN: x² = x + 1 We want to determine the value of x³ So, let''s take the given equation and multiply both sides by x to get: (x)(x²) = (x)(x + 1) Simplify: x³ = x² + x Check the answer choices. . . . . x² + x is not there! At this points, we need to use the given information to ...”
April 23, 2018
Brent@GMATPrepNow posted a reply to Three cannons are firing at a target. in the Problem Solving forum
“P[all shots hit target] is not the complement of P[no shots hit target] If what is the opposite of "none of the shots hit the target"? Well, it''s can be 1 shot hits target or 2 shots hit target or all 3 shots hit target. So, if we''re going to use the complement here, we must ...”
April 22, 2018
Brent@GMATPrepNow posted a reply to Three cannons are firing at a target. in the Problem Solving forum
“P(1st MISSES target) = 1 - P(1st HITS target) = 1 - 0.3 = 0.7 P(2nd MISSES target) = 1 - P(2nd HITS target) = 1 - 0.4 = 0.6 P(3rd MISSES target) = 1 - P(3rd HITS target) = 1 - 0.5 = 0.5 ---------------------------- P(none hit the target) = P(1st misses target AND 2nd misses target AND 3rd ...”
April 22, 2018
Brent@GMATPrepNow posted a new topic called Set T consists of 82 consecutive odd integers. If the sum of in the Problem Solving forum
“Set T consists of 82 consecutive odd integers. If the sum of the integers is 3⁸ - 165, what is the median of set T? A) 78 B) 80 C) 82 D) 84 E) 86 Answer: A Source: www.gmatprepnow.com Estimated difficulty level: 650-700 Cheers, Brent”
April 21, 2018
Brent@GMATPrepNow posted a new topic called Set T consists of 100 consecutive odd integers. If k is an i in the Problem Solving forum
“Set T consists of 100 consecutive odd integers. If k is an integer, which of the following CANNOT equal the median of set T? A) k² - k - 6 B) k² + 8k + 15 C) 4k² + 4k + 1 D) k³ - 4k² - k E) 3k³ - 27k² Answer: C Source: www.gmatprepnow.com Estimated difficulty level: 650-700 ...”
April 21, 2018
Brent@GMATPrepNow posted a reply to A toy store regularly sells all stock at a discount of in the Problem Solving forum
“Your solution is great, but you can save some time by using the fact that the answer choices are spread out nicely. To get the LOWEST possible price (after the two discounts), we must apply the biggest discount (which is a 40% discount) So, AFTER the 40% discount, customers will pay 60% of ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to The "prime sum" of an integer n greater than 1 is in the Problem Solving forum
“This question requires us to find the prime factorization of the answer choices A. 440 = (2)(2)(2)(5)(11). PRIME SUM = 2 + 2 + 2 + 5 + 11 = 22 B. 512 = (2)(2)(2)(2)(2)(2)(2)(2)(2) PRIME SUM = 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 + 2 = 18 C. 620 = (2)(2)(5)(31) PRIME SUM = 2 + 2 + 5 + 31 = 40 ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to If x and y are integers, is x+y an even in the Data Sufficiency forum
“Target question: Is x+y an even integer? Statement 1: x+3y is even There are 4 possible cases to consider. Let''s test them all Case a: x is ODD and y is ODD. Notice that x +3y = ODD + (3)(ODD) = ODD + ODD = EVEN. In this case, x + y = ODD + ODD = EVEN. So, the answer to the target ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to If the sum of the squares of two positive integers is 106, w in the Problem Solving forum
“Your solution is perfect. I can''t think of a different approach. Cheers, Brent”
April 20, 2018
Brent@GMATPrepNow posted a reply to If -3x < 6, which of the following must be true? in the Problem Solving forum
“Given: -3x < 6 Divide both sides by -3 to get: x > -2 Answer: D Cheers, Brent”
April 20, 2018
Brent@GMATPrepNow posted a reply to if A = P^Q what is the value of A if in the Problem Solving forum
“Given: A = P^Q Given: P = -1 Take A = P^Q and replace P with -1 to get: A = (-1 )^Q So, the value of A depends on the value of Q. Let''s test some different values of Q. If Q = 1, then A = (-1 )^1 = -1 If Q = 2, then A = (-1 )^2 = (-1)(-1) = 1 Since we can have two different values ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to A certain restaurant offers 8 different salads in the Problem Solving forum
“Take the task of creating a meal and break it into stages. Stage 1: Select 1 salad There are 8 different salads from which to choose, so we can complete stage 1 in 8 ways Stage 2: Select 1 main course There are 5 different main courses from which to choose, so we can complete stage 2 in ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to If 8^x = 2^12, what is x? in the Problem Solving forum
“We need to rewrite the powers with the SAME BASES. In this case, we can rewrite them with a common base of 2 Given: If 8^x = 2^12, what is x? Rewrite 8 as 2³ to get: (2³)^x = 2^12 Apply Power of a Power rule to get: 2^(2x) = 2^12 So, we can conclude that: 2x =12 Solve: x = 6 Answer: ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to What is the value of y? in the Data Sufficiency forum
“Target question: What is the value of y? Statement 1: y² + 8y + 16 = 0 Factor to get: (y + 4)(y + 4) = 0 So, y MUST equal -4 Since we can answer the target question with certainty, statement 1 is SUFFICIENT Statement 2: y < 0 If y is NEGATIVE, then there are infinitely many ...”
April 20, 2018
Brent@GMATPrepNow posted a reply to 200 is what percent of 40? in the Problem Solving forum
“40 is 100% of 40 So, 500 must be MORE THAN 100% of 40 We can eliminate A, B, C, and D Answer: E Cheers, Brent”
April 20, 2018
Brent@GMATPrepNow posted a reply to GMATPrep Practice Exam Problem 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” April 19, 2018 Brent@GMATPrepNow posted a reply to Which of the following must be equal to 300% in the Problem Solving forum “p % = p/100 So, for example, 19% = 19/100 and 245% = 245/100 So, 300% of the value of x = 300/100 of x = (300/100)(x) = 3x = D Cheers, Brent” April 19, 2018 Brent@GMATPrepNow posted a reply to What was the percent increase in the value of a certain in the Data Sufficiency forum “Target question: What was the percent increase in the value of a certain antique from January 1, 1981, to December 31, 1981? Percent increase = 100(new - old)/old So, we can answer the target question if we have the OLD value and the NEW value. Statement 1: The value of the antique on ...” April 18, 2018 Brent@GMATPrepNow posted a reply to 200 is what percent of 40? in the Problem Solving forum “Let p = the percent So, we get: 200 = p percent of 40 Rewrite as: 200 = (p/100)(40) So, we get: 200 = (40p)/100 Simplify right side: 200 = (2p)/5 Multiply both sides by 5 to get: 1000 = 2p Solve: p = 500 Answer: E Cheers, Brent” April 18, 2018 Brent@GMATPrepNow posted a reply to A certain office supply store stocks 2 sizes of in the Problem Solving forum “There are two different cases to consider: 1) All 3 pads the same color 2) The 3 pads are 3 different colors Case 1: All 3 pads the same color Take the task of packaging pads and break it into stages. Stage 1: Select a size There are 2 possible sizes, so we can complete stage 1 in 2 ...” April 18, 2018 Brent@GMATPrepNow posted a reply to A certain fruit stand sold apples for$0.70 each and in the Problem Solving forum
“Here''s an approach where we test the POSSIBLE SCENARIOS. FACT #1: (total cost of apples) + (total cost of bananas) = 630 CENTS FACT #2: total cost of bananas is DIVISIBLE by 50, since each banana costs 50 cents. Now let''s start testing POSSIBLE scenarios. Customer buys 1 apple. 1 ...”
April 17, 2018
Brent@GMATPrepNow posted a reply to In the quotient a/b positive, which of the following in the Problem Solving forum
“Another approach... The key word here is MUST So, if we can find values of a and b that make an answer choice FALSE, then we can eliminate that answer choice. For example, a = -3 and b = -1 satisfies the given condition that a/b is positive Now take the answer choices and plug in a = -3 ...”
April 17, 2018
Brent@GMATPrepNow posted a reply to In the quotient a/b positive, which of the following in the Problem Solving forum
“GIVEN: a/b is positive This means that a and b have the SAME SIGN (e.g., both are negative or both are positive) Scan the answer choices.... Since a and b have the SAME SIGN, we know that the product ab must be positive Answer: C Cheers, Brent”
April 17, 2018
Brent@GMATPrepNow posted a reply to If a two digit integer is divided by an integer formed by re in the Problem Solving forum
“How about 89 divided by 98? 89 divided by 98 equals 0 with remainder 89 I don''t see 89 as an answer choice. Am I missing something? Cheers, Brent”
April 17, 2018
beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum
“bjedgert has been removed.”
April 16, 2018
Brent@GMATPrepNow posted a reply to On Wednesday morning a fortune cookie machine ran in the Data Sufficiency forum
“Target question: At what time did it completely fill the order that morning? For this work question, we need to know that time = (output)/(rate) Statement 1: The machine produces 300 units per hour. Okay, so we know the machine''s rate, but we don''t know anything about the size of the ...”
April 16, 2018
Brent@GMATPrepNow posted a reply to A regular polygon can be constructed with a compass and in the Problem Solving forum
“I agree with you, regor60. Cheers, Brent”
April 16, 2018
Brent@GMATPrepNow posted a reply to Last year, Christine received 12 monthly paychecks. Each of in the Problem Solving forum
“Another approach is to use 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) + ... In this question, the proportion of $4500 paychecks = 4/12 = 1/3 And the proportion ...” April 15, 2018 Brent@GMATPrepNow posted a reply to Is standard deviation of Set A > standard deviation of Se in the Data Sufficiency forum “Target question: Is standard deviation of Set A > standard deviation of Set B? Head straight to... Statements 1 and 2 COMBINED We can quickly come up with 2 cases that satisfy BOTH statements: Case a: Set A = {4, 4, 4, 4} and set B = {1, 2, 3}. Notice that both statements are ...” April 15, 2018 Brent@GMATPrepNow posted a reply to For any real number x, the operator & is defined as in the Problem Solving forum “Let''s look at a few examples of this operator (&) in action. If &(x) = x(1 − x), then... &(3) = 3(1 − 3) = 3(-2) = -6 &(7) = 7(1 − 7) = 7(-6) = -42 &(-5) = -5(1 − -5) = (-5)(6) = -30 And now..... &(p+1) = (p+1)(p+1)] = (p + 1)(-p) Now onto the ...” April 15, 2018 Brent@GMATPrepNow posted a reply to What is the remainder when k^2 is divided by 8? in the Data Sufficiency forum “Target question: What is the remainder when k² is divided by 8? Statement 1: When k is divided by 2, the remainder is 1. This tells us that k is one greater than some multiple of 2. So, we can write k = 2n + 1, where n is some integer. If k = 2n + 1, then k² = (2n + 1)² = 4n² + 4n + ...” April 15, 2018 Brent@GMATPrepNow posted a reply to probability in the Problem Solving forum “Your new question: Two people are randomly selected from the group of five people: Amir, Brian, Claudia, Dhana and Ebo. What is the probability that Amir & Brian are BOTH selected? The correct answer to that question is 1/10. You''re getting 2/10 as your answer, because you''re treating the ...” April 14, 2018 Brent@GMATPrepNow posted a reply to Is positive integer n – 1 a multiple of 3? in the Data Sufficiency forum “Target question: Is positive integer n – 1 a multiple of 3? Statement 1: n³ – n is a multiple of 3 Let''s do some FACTORING n³ – n = n(n² - 1) = n(n + 1)(n - 1) So, statement 1 tells us that n(n + 1)(n - 1) is a multiple of 3 Notice that (n-1), n and (n+1) are 3 CONSECUTIVE ...” April 14, 2018 Brent@GMATPrepNow posted a reply to On a Monday in a certain restaurant, 20 percent of the in the Problem Solving forum “On a Monday in a certain restaurant, 20 percent of the 180 customers ordered the daily special. 10% of 180 = 18 So, 20% of 180 = 36 So, 36 people ordered the daily special on MONDAY On Tuesday, only 10 percent of the 120 customers ordered the special. 10% of 120 = 12 So, 12 people ordered ...” April 14, 2018 Brent@GMATPrepNow posted a reply to For the positive integers x, x + 2, x + 4, x + 7, and in the Problem Solving forum “MEAN mean = x + 5 MEDIAN The 5 values are already arranged in ASCENDING order {x, x + 2, x + 4, x + 7, x + 12} So, the median = the middle value = x + 4 The mean is how much greater than the median? In other words x + 5 is how much greater than the x + 4? Answer = (x + 5) - (x + 4) = ...” April 14, 2018 Brent@GMATPrepNow posted a reply to In a survey of 200 college graduates, 30 percent said in the Data Sufficiency forum “We can solve this question 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. Here, we have a population of college graduates, and the two characteristics are: - received ...” April 13, 2018 Brent@GMATPrepNow posted a reply to If x > y, is x > 6 ? (1) (x - 7)(y - 7) = 0 (2) x > in the Data Sufficiency forum “Target question: Is x > 6 ? Given: y < x Statement 1: (x - 7)(y - 7) = 0 There are two possible cases that make this equation true. Either x = 7 OR y = 7 Let''s examine each case: Case a: x = 7. In this case, the answer to the target question is YES, x IS greater than 6 Case b: ...” April 13, 2018 Brent@GMATPrepNow posted a reply to When a positive integer n is divided by 5, the remainder is in the Data Sufficiency forum “Target question: What is the remainder when n is divided by 3? Given: When positive integer 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 the possible values of N ...” April 13, 2018 Brent@GMATPrepNow posted a reply to A train travels at the rate of 10 miles/hr for the first in the Problem Solving forum “First check the answer choices (ALWAYS check the answer choice before deciding on an approach to a question) We see that all answer choices are between 8 hours and 10 hours. So, let''s test the answer choices, starting with 8 hours, and then go from there (if need be). A) 8 hours Distance ...” April 13, 2018 beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum “Happy to help. Your account has been deleted.” April 12, 2018 Brent@GMATPrepNow posted a reply to Is x>0? in the Data Sufficiency forum “Target question: Is x POSITIVE? Statement 1: (x + y )² > (x - y)² Take: (x + y )² > (x - y)² Expand and simplify both sides to get: x² + 2xy + y ² > x² - 2xy + y ² Subtract x² from both sides: 2xy + y ² > -2xy + y ² Subtract y² from both sides: 2xy > -2xy Add ...” April 12, 2018 Brent@GMATPrepNow posted a reply to The arithmetic mean of the list of numbers in the Problem Solving forum “The arithmetic mean of the list of numbers above is 4. So, (3 + k + 2 + 8 + m + 3)/6 = 4 Multiply both sides by 6 to get: 3 + k + 2 + 8 + m + 3 = 24 Simplify: 16 + k + m = 24 Subtract 16 from both sides to get: k + m = 8 If k and m are integers k ≠ m, what is the median of the list? ...” April 12, 2018 Brent@GMATPrepNow posted a reply to A bag consists of 20 marbles, of which 5 are blue, 9 are red in the Problem Solving forum “Your solution is perfect. If you''re looking for an alternate approach, one option is to use the complement: P(red or white) = 1 - P(NOT red or white) = 1 - P(blue) = 1 - 5/20 = 15/20 = 3/4 Answer: A” April 11, 2018 beatthegmat posted a reply to Delete account in the Suggestions and Feedback forum “Hi Dhinda, Your account has been deleted. Best, The BeatTheGMAT Team” April 11, 2018 Brent@GMATPrepNow posted a reply to If a copier makes 3 copies every 4 seconds, then continues in the Problem Solving forum “The above solution is perfect, but here''s another approach... We can apply some number sense in a series of steps GIVEN: Copier makes 3 copies every 4 seconds So: the copier makes 45 copies every 60 seconds In other words, the copier makes 45 copies every 1 MINUTE Keep going: the copier ...” April 9, 2018 Brent@GMATPrepNow posted a reply to OG2015 DS If n + k = m in the Data Sufficiency forum “I''d typically use the same approach that Ceilidh used, but here''s one more approach... Target question: What is the value of k? Given: n + k = m Statement 1: n = 10 Let''s TEST some values There are several values of m, n and k that satisfy statement 1. Here are two: Case a: m = ...” April 9, 2018 Brent@GMATPrepNow posted a reply to value of y in the Problem Solving forum “There are infinitely many right triangles that have an area of 1. So, one approach is to find a triangle that meets the given conditions, and see what conclusions we can draw. Here''s one such right triangle: https://s26.postimg.org/ctwnpq92d/image.png This meets the conditions that the ...” April 9, 2018 Brent@GMATPrepNow posted a reply to Is a=−b? in the Data Sufficiency forum “Target question: Is a = −b? This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: Take the equation a = −b and add b to both sides to get: a + b= 0 So, we get.... REPHRASED target question: Is a + b= 0? ...” April 8, 2018 Brent@GMATPrepNow posted a reply to During Thanksgiving weekend, a car rental company rented 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 vehicles, and the two characteristics are: ...” April 8, 2018 Brent@GMATPrepNow posted a reply to Three gnomes and three elves sit down in a row of six... in the Problem Solving forum “Your solution is perfect. It''s also how I would have solved it. Cheers, Brent” April 7, 2018 Brent@GMATPrepNow posted a reply to Which expression is equivalent to (5x − 3y)^2? in the Problem Solving forum “One option is to use the FOIL method to expand the product (that''s the solution I''d typically use) However, we can also use this approach: First recognize that we''re looking for an expression that''s EQUIVALENT to (5x − 3y)^2 for all values of x and y So, for example, let''s determine the ...” April 7, 2018 Brent@GMATPrepNow posted a reply to OG2015 PS If x = 1- 3t in the Problem Solving forum “GIVEN: x = 1- 3t y = 2t - 1 We want x = y Substitute to get: 1- 3t = 2t - 1 Add 3t to both sides: 1 = 5t - 1 Add 1 to both sides: 2 = 5t Divide both sides by 5 to get: 2/5 = t Answer: D Cheers, Brent” April 7, 2018 Brent@GMATPrepNow posted a reply to A basketball coach will select the members of a five-player in the Problem Solving forum “P(John and Peter both on the team) = (# of teams that include both John and Peter) / (total # of 5-person teams possible) a) # of teams that include both John and Peter - Put John and Peter on the team. This can be accomplished in 1 way - Select the remaining 3 team-members from the remaining 7 ...” April 7, 2018 Brent@GMATPrepNow posted a reply to The number of stamps that Kaye and Alberto had were... in the Problem Solving forum “One option is to solve the question using TWO VARIABLES. Let K = # of stamps K had after the exchange Let A = # of stamps A had after the exchange This means that K+10 = # of stamps K had before the exchange This means that A-10 = # of stamps A had before the exchange Note: Our goal is to ...” April 4, 2018 Brent@GMATPrepNow posted a reply to Five years ago Jim was three times as old as Raoul in the Problem Solving forum “Let R = Raoul''s PRESENT age So, R - 5 = Raoul''s age 5 YEARS AGO Five years ago .... Monica was six years older than Raoul was. So, (R - 5) + 6 = Monica''s age 5 YEARS AGO In other words, R + 1 = Monica''s age 5 YEARS AGO Five years ago Jim was three times as old as Raoul was So, 3(R - 5) ...” April 3, 2018 beatthegmat posted a new topic called An Insider’s Guide to the GRE® General Test in the GMAT Strategy forum “Are you getting ready for the GRE<sup>®</sup> General Test? The test has several smart features that can help you do your best, but you’ll still have to do your part. The more prepared you are, the more confident you will feel on test day. This overview of the test with tips and ...” April 2, 2018 Brent@GMATPrepNow posted a reply to Is the product abcd negative? in the Data Sufficiency forum “Target question: Is the product abcd negative? Statement 1: a < b < c < d This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of a, b, c, and d that satisfy statement 1. Here are two: Case a: a = -1, b = 1, c = 2 and d = 3. In this case, ...” March 31, 2018 beatthegmat posted a reply to The early Greeks designed a mud-brick temple that mirrored t in the Sentence Correction forum “Please provide OA and source.” March 31, 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 ...” March 31, 2018 Brent@GMATPrepNow posted a reply to How many positive two-digit numbers yield... in the Problem Solving forum “Your approach is perfect. I can''t think of a faster approach. Cheers, Brent” March 31, 2018 Brent@GMATPrepNow posted a reply to PS Question: Division of money in the GMAT Math forum “This, I believe, is a 700+ level question. Cheers, Brent” March 31, 2018 Brent@GMATPrepNow posted a reply to Critical points method for inequality Is x^2 > 1/x? in the Data Sufficiency forum “Target question: Is x² > 1/x ? Statement 1: x² > x First off, this inequality tells us that x ≠ 0 Second, we can conclude that x² is POSITIVE. So, we can safely divide both sides of the inequality by x² to get: 1 > 1/x If 1 > 1/x, then there are two possible cases: ...” March 30, 2018 Brent@GMATPrepNow posted a reply to How many passengers can be seated on a plane with r rows, if in the Problem Solving forum “d double seats will seat 2d passengers t triple seats will seat 3t passengers So, the total number of seats in ONE ROW = 2d + 3t The plane has a total of r rows. So, the TOTAL number of seats = r(2d + 3t) Check the answer choices....not there (at least not in the above form) Expand to get: ...” March 30, 2018 Brent@GMATPrepNow posted a reply to If 50-√7<x<50+√7, then x=? in the Data Sufficiency forum “Target question: What is the value of x? Given: 50 - √7 < x < 50 + √7 √4 = 2 √9 = 3 So, we can say that √7 = 2.something This means: 50 - 2.something < x < 50 + 2.something Simplify to get: 47.something < x < 52.something Statement 1: x is an odd ...” March 30, 2018 Brent@GMATPrepNow posted a reply to Grammer in the Sentence Correction forum “With NONE, we examine the part after NONE to see whether it''s singular or plural. Here we have "None of my friends" (plural), so we need plural ARE.... Cheers, Brennt” March 30, 2018 Brent@GMATPrepNow posted a reply to PS Question: Division of money in the GMAT Math forum “Another approach: This time, let K = the money REMAINING after Ann has received her portion AND after Bob has taken$4. At this point, Bob receives 1/3 of K, and Chloe gets the rest. This means that Chloe receives 2/3 of K Since Chloe receives $32, we can say that: (2/3)K = 32 Multiply ...” March 30, 2018 Brent@GMATPrepNow posted a reply to PS Question: Division of money in the GMAT Math forum “Note: we don''t need to consider Ann''s portion in the solution. Let K = the money remaining AFTER Ann has received her portion and then go from there. We''re told that, once we remove Bob''s portion, we have$32 for Chloe. So, we get K - Bob''s $= 32 Bob receives$4 plus one-third of what ...”
March 30, 2018
Brent@GMATPrepNow posted a reply to When 1/10 percent of 5,000 is subtracted from 1/10 of 5,000 in the Problem Solving forum
“1/10 percent of 5,000 10% of 5,000 = 500 1% of 5,000 = 50 0.1% of 5,000 = 5 In other words, 1/10 percent of 5,000 = 5 1/10 of 5,000 1/10 of 5,000 = (1/10)(5,000) = 5000/10 = 500 DIFFERENCE = 500 - 5 = 495 Answer: D Cheers, Brent”
March 29, 2018
Brent@GMATPrepNow posted a reply to Car X is 40 miles west of Car Y. Both cars are traveling in the Problem Solving forum
“Here''s one approach: Let''s let Car X''s original position be the initial starting point. So, when Car X is at the initial starting point, Car Y has already traveled 40 miles. My word equation involves the conditions when Car X catches up to Car Y. At that point, we can say: Car X''s ...”
March 29, 2018
Brent@GMATPrepNow posted a reply to In a sequence of 8 consecutive integers, how much greater is in the Problem Solving forum
“Let''s test 8 consecutive integers How about: 1, 2, 3, 4, 5, 6, 7, 8 sum of the first four integers = 1 + 2 + 3 + 4 = 10 sum of the last four integers = 5 + 6 + 7 + 8 = 26 Difference = 26 - 10 = 16 Answer: C Cheers, Brent”
March 29, 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 ...”
March 29, 2018
Brent@GMATPrepNow posted a reply to Health insurance Plan A requires the insured to pay $1000 or in the Problem Solving forum “Here''s an algebraic approach: Let T = TOTAL COST Plan A: Person pays EITHER$1000 OR 0.5T, whichever is LESS Plan B: Person pays $300 plus 20% of anything over$300. In other words, the person pays $300 + 0.2(T - 300) Since Plan A has two different scenarios, we need to test both. That ...” March 29, 2018 Brent@GMATPrepNow posted a reply to A certain plumber charges$92 for each job completed in the Data Sufficiency forum
“Oops!!!!!!!!!!! ”
March 27, 2018
Brent@GMATPrepNow posted a reply to Bob drives at an average rate of 50 mph from Berkeley... in the Problem Solving forum
“Your solution is perfect! Cheers, Brent”
March 27, 2018
beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum
“Complete”
March 27, 2018
Brent@GMATPrepNow posted a reply to Last year, for every 100 million vehicles that traveled on.. in the Problem Solving forum
“We can use equivalent ratios to solve this. # cars/# accidents: 100,000,000/96 = 3,000,000,000/x Rewrite with exponents: 10⁸/96 = (3)(10⁹) /x Cross multiply to get: (10⁸)(x) = (3)(10⁹)(96) 96 is close enough to 100, so let''s replace 96 with 100 to get: (10⁸)(x) = (3)(10⁹)(100) ...”
March 27, 2018
Brent@GMATPrepNow posted a reply to Is x < y? in the Data Sufficiency forum
“Don''t subtract inequalities Doing so can yield erroneous statements. Consider this example: 5 < 6 0 < 9 When we subtract these inequalities , we get 5 - 0 < 6 - 9 Evaluate to get 5 < -3 (not true) Cheers, Brent”
March 27, 2018
Brent@GMATPrepNow posted a reply to A code is to be made by arranging 7 letters. Three of the in the Problem Solving forum
“-------ASIDE------------------------ When we want to arrange a group of items in which some of the items are identical, we can use something called the MISSISSIPPI rule. It goes like this: If there are n objects where A of them are alike, another B of them are alike, another C of them are alike, ...”
March 27, 2018
Brent@GMATPrepNow posted a reply to A car traveled from Los Angeles to San Francisco in 6 hours in the Problem Solving forum
“A car traveled from Los Angeles to San Francisco in 6 hours at an average rate of x miles per hour. Distance = (time)(rate) So, distance from Los Angeles to San Francisco = (6)(x) = 6x miles The car returned along the same route at an average rate of y miles per hour We know the distance = 6x ...”
March 27, 2018
Brent@GMATPrepNow posted a reply to The probability that team A will not win the tournament is in the Problem Solving forum
“The probability that team A will NOT win the tournament is 80% In other words, the probability that team A will NOT win the tournament is 0.8 So P(team A WILL win the tournament) = 1 - 0.8 = 0.2 The probability that team B will NOT win the tournament is 60% So P(team B WILL win the tournament) ...”
March 26, 2018
Brent@GMATPrepNow posted a reply to Which of the following is the greatest? in the Problem Solving forum
“From a strictly subjective standpoint, I think (1 + 2)^5 is pretty great <i class="em em-grimacing"></i> A. (1 + 2)^5 = (3)^5 = 243 B. 10^3 = 1,000 C. (1^2 + 2^2)^4 = (1 + 4)^4 = (5)^4 = 625 D. (2^2 + 2^2 + 2^2)^3 = (4 + 4 + 4)^3 = (12)^3 ASIDE: I won''t bother ...”
March 26, 2018
Brent@GMATPrepNow posted a reply to The average of m, n, and p is q and the average q and r is s in the Problem Solving forum
“Your algebraic approach is perfect. Another approach is the INPUT-OUTPUT approach. First find some values of m, n, p, q, r and s that satisfy all of the given information. For example, the following values satisfy all of the given information: m = 1, n = 1, p = 1, q = 1, r = 1 and s = 1 ...”
March 26, 2018
Brent@GMATPrepNow posted a reply to How many ways can the five digits 3, 3, 4, 5, 6 be arranged in the Problem Solving forum
“One approach here is to first IGNORE the restriction (about the 3''s not appearing together) and then subtract all of the outcomes that break that restriction. I''m sure someone will show that approach. Here''s another approach: Take the task of arranging the 5 digits and break it into ...”
March 25, 2018
Brent@GMATPrepNow posted a reply to City X has a population 4 times as great as the population in the Problem Solving forum
“A nice (fast) approach is to plug in some numbers that meet the given conditions. City Y has a population twice as great as the population of City Z Let''s say the population of City Z is 1 person This means the population of City Y is 2 people City X has a population 4 times as great as ...”
March 25, 2018
Brent@GMATPrepNow posted a reply to A card shop contains 5 birthday cards, 5 holiday cards... in the Problem Solving forum
“Let''s first rewrite our probability and then apply probability rules. P(All 3 cards the same type) = P(1st card is ANY type AND 2nd card matches type of 1st card AND 3rd card matches type of 1st card) = P(1st card is ANY type) x P(2nd card matches type of 1st card) x P(3rd card matches ...”
March 25, 2018
Brent@GMATPrepNow posted a reply to OG 18 - DS- Q362 - How to solve it quickest? in the GMAT Math forum
“One 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. Here, we have a population of people, and the two characteristics are: - member of Club X or not a member of Club ...”
March 25, 2018
Brent@GMATPrepNow posted a reply to What is the average (arithmetic mean) of eleven in the Data Sufficiency forum
“There''s a nice rule that says, "In a set where the numbers are equally spaced, the mean will equal the median." Since the consecutive integers are equally-spaced, their mean and median will be equal. Target question: What is the average of eleven consecutive integers? ...”
March 24, 2018
Brent@GMATPrepNow posted a reply to The product of all the prime numbers less than... in the Problem Solving forum
“The numbers are very spread apart (each answer choice is 10 times greater than the next answer choice). This means we can be quite AGGRESSIVE with our estimation. One approach: We have the product (2)(3)(5)(7)(11)(13)(17)(19) Let''s see if we can group the numbers to get some approximate ...”
March 24, 2018
Brent@GMATPrepNow posted a reply to If m and n are prime numbers, is the remainder when in the Data Sufficiency forum
“Target question: When 3m is divided by n, is the remainder greater than 5? Given: m and n are prime numbers Statement 1: m < 10 Let''s TEST some values. There are several values of m and n that satisfy statement 1. Here are two: Case a: m = 2 and n = 7. Here 3m = 6, so 3m divided ...”
March 24, 2018
Brent@GMATPrepNow posted a reply to Five Most Common Mistakes on GMAT Data Sufficiency in the Data Sufficiency forum
“Great initiative! Here are 4 more videos related to possible Data Sufficiency mistakes: - Common Mistakes - Part I: https://www.youtube.com/watch?v=iACq36scVYQ - Common Mistakes - Part II: https://www.youtube.com/watch?v=yEBRAR5jXlY - Common GMAT Data Sufficiency Myths - Part I: ...”
March 23, 2018
Brent@GMATPrepNow posted a reply to Pete has some apples. He sold 40% more than he ate... in the Problem Solving forum
“Your approach is perfect! Once we know that x = 70/1.4, we have a few ways to evaluate this. Here''s one way.... x = 70/1.4 = 700/14 (I multiplied top and bottom by 10 to eliminate the decimal) = 100/2 (I divided top and bottom by 7) = 50 Cheers, Brent”
March 23, 2018
Brent@GMATPrepNow posted a reply to The greatest common factor of two positive integers is X... in the Problem Solving forum
“--------ASIDE---------------------- There''s a nice rule that says: (greatest common divisor of A and B)(least common multiple of A and B) = AB Example: A = 10 and B = 15 Greatest common divisor of 10 and 15 = 5 Least common multiple of 10 and 15 = 30 Notice that these values satisfy the above ...”
March 23, 2018
Brent@GMATPrepNow posted a reply to In country Z, 10% of the people do not have a university... in the Problem Solving forum
“I thought I''d point out that Jay''s and 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 people, and the two characteristics are: - has a university diploma or ...”
March 23, 2018
Brent@GMATPrepNow posted a reply to A street vendor sells only hot dogs and hamburgers, and at.. in the Problem Solving forum
“Here''s an approach that uses three variables. Let D = # of hotdogs the vendor STARTED with Let H = # of hamburgers the vendor STARTED with Let x = # of hotdogs sold At the beginning of the day has a ratio of two hot dogs for every one hamburger. So, D/H = 2/1 Cross multiply to get: D = ...”
March 23, 2018
Brent@GMATPrepNow posted a reply to In a 40-mile trip, the first 20 miles were traveled in in the Problem Solving forum
“Here''s one approach: The total distance is 40 miles, and we want the average speed to be 60 miles per hour. Average speed = (total distance)/(total time) So, we get: 60 = (40 miles)/(total time) Solve equation to get: total time = 2/3 hours So, the TIME for the ENTIRE 40-mile trip needs to ...”
March 22, 2018
Brent@GMATPrepNow posted a reply to According to the directions on a packet of smoothie mix in the Problem Solving forum
“Here''s a similar question to practice with: https://www.beatthegmat.com/cans-of-oj-concentrate-t281253.html Cheers ,Brent”
March 22, 2018
Brent@GMATPrepNow posted a reply to Is a + b > c + d? in the Data Sufficiency forum
“Target question: Is a + b > c + d ? Statement 1: a > c Since we have no information about b or d, we cannot determine whether a + b > c + d Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: d < b Since we have no ...”
March 22, 2018
Brent@GMATPrepNow posted a reply to if d is a positive integer, is √d an integer ? in the Data Sufficiency forum
“NOTE: I have added brackets to the question to avoid ambiguity. Asde: This is very similar to this question: http://www.beatthegmat.com/og-quant-review-ps-q31-t268233.html#688190 Target question: Is √d an integer? Given: d is a positive integer Statement 1: √(9d) is an ...”
March 22, 2018
Brent@GMATPrepNow posted a reply to If the positive integer n is greater than 6, what is in the Data Sufficiency forum
“Here''s another (longer!) approach (MItch''s solution is much nicer, but this one will also work) Target question: What is the remainder when n is divided by 6? Given: Positive integer n is greater than 6 Statement 1: When n is divided by 9, the remainder is 2. ...”
March 22, 2018
Brent@GMATPrepNow posted a reply to Right triangle PQR is to be constructed in the xy-plane... in the Problem Solving forum
“Take the task of building triangles and break it into stages. Stage 1: Select any point where the right angle will be (point P). The point can be selected from a 10x11 grid. So, there 110 points to choose from. This means that stage 1 can be completed in 110 ways. Stage 2: Select a point ...”
March 21, 2018
Brent@GMATPrepNow posted a reply to If A and B are positive integers greater than 1 such that in the Problem Solving forum
“Yes you are correct. The statement tells us that EITHER both integers are odd OR both integers are even. Cheers, Brent”
March 21, 2018
Brent@GMATPrepNow posted a reply to |y - 1/2| < 11/2 in the Problem Solving forum
“---------ASIDE----------------------------------------------- When solving inequalities involving ABSOLUTE VALUE, there are 2 things you need to know: Rule #1: If |something| < k, then –k < something < k Rule #2: If |something| > k, then EITHER something > k OR something < ...”
March 21, 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 ...”
March 20, 2018
Brent@GMATPrepNow posted a reply to How many gallons of milk that is 10 percent butter-fat... in the Problem Solving forum
“One option is to focus on the butter fat We begin with 8 gallons of milk that is 35 percent butter-fat So, the volume of butter fat = 35% of 8 = (0.35)(8) = 2.8 gallons of butter fat (to begin) Let x = number of gallons of milk that is 10 percent butter-fat to be added to the initial 8 ...”
March 20, 2018
Brent@GMATPrepNow posted a reply to OG - SC Question 74 in the Sentence Correction forum
“Important: When a sentence begins with a with noun modifier (as it does in the original sentence), stop at the comma and ask the question that the modifier raises So, once we read, Despite its covering the entire planet, we should stop and ask . . . "What covers the entire planet?" ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to In the past, most children who went sledding in the winter s in the Critical Reasoning forum
“Summarize the argument.. PREMISE: Kids used to use wooden sleds PREMISE: 10 years ago, plastic sleds came PREMISE: plastic sleds are faster and harder to steer and slow PREMISE: more kids injured last year than 10 years ago CONCLUSION: plastic sleds are more dangerous Now, check each ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to In how many ways can two integers m and n, with m > n, be in the Problem Solving forum
“A nice rule says: the number of integers from x to y inclusive equals y - x + 1 32 - 12 + 1 = 21 So, there are 21 numbers from which to choose NOTE: the order in which we select the numbers does not matter because, once we have selected the 2 numbers, we''ll let m equal the larger value (to ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to If S = {0, 4, 5, 2, 11, 8}, how much greater than the in the Problem Solving forum
“To find the median, first arrange the values in ASCENDING ORDER: {0, 2, 4, 5, 8, 11} Since the set has an EVEN number values, the median will be the average of the two middlemost numbers. So, median = (4 + 5)/2 = 9/2 = 4.5 Mean = (sum of all values in the set)/(number of values in the set) = ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to Which of the following equations has a solution in common in the Problem Solving forum
“Step 1: Solve the given equation: x² - 2x - 15 = 0 This is a quadratic set equal to zero, so let''s factor to get: (x - 5)(x + 3)=0 So, we have two solutions (roots): x = 5 or x = -3 Step 2: Solve the equations in the answer choices to see which one has a root (solution) of x = 5 or x = -3 ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to Given 2x + y + z = 3 and 5x + 3y + z = 8, what is the in the Problem Solving forum
“Another approach is to look for values of x, y and z that satisfy BOTH equations (2x + y + z = 3 and 5x + 3y + z = 8). One set of values is x = 1, y = 1 and z = 0 (there are infinitely many sets of values that satisfy both equations) What is the value of x + y - z ? x + y - z = 1 + 1 - 0 = 2 ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to The average (arithmetic mean) of a professor's salary at in the Data Sufficiency forum
“I think you''re missing some information above. Target question: Is the average salary of a professor at University D at least 25 percent higher than that for a professor at University M? NOTE: In order to determine the average salary of a professor, we need to know the amount spent on ...”
March 19, 2018
Brent@GMATPrepNow posted a reply to Unable to improve in GMAT RC(Accuracy: 65%) in the Reading Comprehension forum
“A lot of people struggle with the time constraints of the Verbal section. If you consistently run out of time on the Verbal section, I suggest that you look for certain questions to guess and skip. For example, if you find Assumption CR questions particularly difficult, you might skip any of these ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to Tom and Samuel are riding motorcycles down the highway in the Data Sufficiency forum
“Target question: How many minutes before Tom is 3 miles ahead of Samuel? Given: Tom is now 2 miles ahead of Samuel Statement 1: Tom is traveling at 70 miles per hour and Samuel is traveling at 60 miles per hour. We don''t really need to apply answer formulas here. We need only ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to Having received his weekly allowance, John spent 3/5 of in the Problem Solving forum
“Let w = John’s weekly allowance Having received his weekly allowance, John spent 3/5 of his allowance at the arcade If John spent 3/5 of his allowance, then he has 2/5 REMAINING So, (2/5)(w) = allowance REMAINING The next day he spent one third of his remaining allowance at the toy store ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to Unable to improve in GMAT RC(Accuracy: 65%) in the Reading Comprehension forum
“Hi sd2611, What do you feel is the main barrier to RC questions for you? Do you have enough time to read the passage and answer the related questions? Do you find it difficult to summarize each paragraph in a concise manner? Are there issues with vocabulary? Or perhaps there are other ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to The ratio of the number of boys to the number of girls in in the Problem Solving forum
“Another approach: There are 5 more girls than boys in the club Let G = # of girls in club So G-5 = # of boys in club The ratio of the number of boys to the number of girls in a certain school club is 3 to 4. We can write (G-5)/G = 3/4 Cross multiply: 4(G-5) = 3G Expand: 4G - 20 = 3G ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to The ratio of the number of boys to the number of girls in in the Problem Solving forum
“One approach: The ratio of the number of boys to the number of girls in a certain school club is 3 to 4. So, some possible scenarios are: 3 boys and 4 girls 6 boys and 8 girls 9 boys and 12 girls . . . There are 5 more girls than boys in the club So, keep listing scenarios until we ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive integers, and 1 is the greatest in the Problem Solving forum
“Consider these two cases. case 1: x = 3 and y = 2. This satisfies the condition that 1 is the greatest common divisor of x and y In this case 2x = 2(3) = 6, and 3y = 3(2) = 6 So, the greatest common divisor of 2x and 3y is 6 case 2: x = 1 and y = 1. This satisfies the condition that 1 is ...”
March 18, 2018
Brent@GMATPrepNow posted a reply to John and Peter are among the nine players a basketball... in the Problem Solving forum
“We want: a) # of teams that include both John and Peter b) total # of 5-person teams possible a) # of teams that include both John and Peter Put John and Peter on the team (this can be accomplished in 1 way) Select the remaining 3 team-members from the remaining 7 players (this can be ...”
March 17, 2018
Brent@GMATPrepNow posted a reply to Last Sunday a certain store sold copies of newspaper a for.. in the Problem Solving forum
“If you''re not sure how to proceed with this question, or if you''re behind on time and you want to catch up, you can give yourself a 50-50 chance in about 10 seconds. To do so, we''ll see what happens when we use an EXTREME value for p. Say p = 100 In other words, 100% of the newspapers sold ...”
March 16, 2018
Brent@GMATPrepNow posted a reply to Last Sunday a certain store sold copies of newspaper a for.. in the Problem Solving forum
“Let''s use the INPUT-OUTPUT approach. Let''s say that Newspaper A accounted for 20% of all newspapers sold. In other words, p = 20 This means that Newspaper B accounted for 80% of all newspapers sold. The question asks us to find the value of r, the percentage of newspaper revenue from ...”
March 16, 2018
Brent@GMATPrepNow posted a reply to If d denotes a decimal, is d ≥ 0.5? in the Data Sufficiency forum
“Target question: Is d ≥ 0.5? Statement 1: When d is rounded to the nearest tenth, the result is 0.5. There are several values of d that satisfy statement 1. Here are two: Case a: d = 0.51 (we get 0.5 when 0.51 is rounded to the nearest tenth). In this case, the answer to the target ...”
March 15, 2018
Brent@GMATPrepNow posted a reply to The rectangle A has a (width) and b (height) and another... in the Problem Solving forum
“Hi AAPL, Your solution is perfect. Once we know that a = 3k, c = 2k, b = 3m and d = 2m, then... Area of rectangle A = ab = (3k)(3m) = 9km Area of rectangle B = cd = (2k)(2m) = 4km So, the ratio of the rectangle A''s area to the rectangle B''s = 9km/4km = 9/4 Answer: D Cheers, Brent”
March 15, 2018
Brent@GMATPrepNow posted a reply to A committee of 2 people is to be selected out of in the Problem Solving forum
“Here''s an approach that uses probability rules. We want P(select at least 1 preacher) 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 ...”
March 15, 2018
beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum
“pareshcs, your account has been successfully deleted.”
March 15, 2018
beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum
“hhjj, your account has been successfully deleted.”
March 15, 2018
Brent@GMATPrepNow posted a reply to When positive integer x is divided by 20, the remainder is 8 in the Problem Solving forum
“There''s a nice rule that say, "If N divided by D equals Q with remainder R, then N = DQ + R" For example, since 17 divided by 5 equals 3 with remainder 2, then we can write 17 = (5)(3) + 2 Likewise, since 53 divided by 10 equals 5 with remainder 3, then we can write 53 = (10)(5) + 3 ...”
March 14, 2018
Brent@GMATPrepNow posted a reply to Seven basketball teams play in a league against each other in the Problem Solving forum
“Take the task of arranging the top 3 teams and break it into stages. Stage 1: Select the 1st place team There are 7 teams to choose from, so we can complete stage 1 in 7 ways Stage 2: Select the 2nd place team Since already selected a team in stage 1, there are now 6 teams remaining to ...”
March 14, 2018
Brent@GMATPrepNow posted a reply to Health insurance Plan A requires the insured to pay $1000... in the Problem Solving forum “Here''s an algebraic approach: Let T = TOTAL COST Plan A: Person pays EITHER$1000 OR 0.5T, whichever is LESS Plan B: Person pays $300 plus 20% of anything over$300. In other words, the person pays $300 + 0.2(T - 300) Since Plan A has two different scenarios, we need to test both. That ...” March 14, 2018 Brent@GMATPrepNow posted a reply to In a given finance lecture, 30% of the students are finance in the Problem Solving forum “This question can be solved using the Double Matrix method. Note: This technique can be used for most questions featuring a population in which each member has two criteria associated with it. Here, the criteria are: - Major (Finance or Non-Finance) - Gender (Female or Male) Since ...” March 14, 2018 Brent@GMATPrepNow posted a reply to If (n+2)!= n!(an^2+bn+c), then abc=? in the Problem Solving forum “First recognize that (n + 2)! = (n + 2)(n + 1)(n)(n - 1)(n - 2)(n - 3)....(3)(2)(1) = (n + 2)(n + 1)(n!) = (n!)(n + 2)(n + 1) The question tells us that (n + 2)! = n!(an² + bn + c) So, we can write: (n!)(n + 2)(n + 1) = n!(an² + bn + c) Divide both sides by n! to get: (n + 2)(n + 1) = an² ...” March 14, 2018 Brent@GMATPrepNow posted a reply to Sentence Correction in the Sentence Correction forum “This question is primarily about PRONOUN REFERENTS. In the original sentence, we have the pronoun it. What does this pronoun refer to? The pronoun refers to the TERM (word) “psychopath” So, if we replace the pronoun IT with its referent TERM “psychopath” we get.... (A) the TERM ...” March 14, 2018 Brent@GMATPrepNow posted a reply to A grocery store sells apples by the pound. If the price per in the Problem Solving forum “let C = CURRENT price per pound So, C - 1 = INCREASED price per pound If the price per pound is increased by$1, $12 will buy 0.4 pounds less of apples than if the price remains at the current level. Let''s first turn this statement into a word equation We can write: pounds of apples that can ...” March 13, 2018 Brent@GMATPrepNow posted a reply to John and Marry were each paid x dollars in advance... in the Problem Solving forum “The problem with your solution is highlighted above in green In order for their hourly wages to be the same, we need (x - y)/8 = (x + y)/10 We need this because hourly wage = (total$ received)/(total hours worked) For more on this, see my solution below. Cheers, Brent”
March 13, 2018
Brent@GMATPrepNow posted a reply to John and Marry were each paid x dollars in advance... in the Problem Solving forum
“Salary Mary''s NET salary was x - y dollars (because Mary gave John y dollars) John''s NET salary was x + y dollars Hours worked Mary worked 8 hours John worked 10 hours In the end, John and Mary received the SAME hourly wage. So, John''s hourly wage = Mary''s hourly wage Hourly ...”
March 13, 2018
Brent@GMATPrepNow posted a reply to Of the 300 employees of a certain company, 65 are... in the Problem Solving forum
“So, there are 300 employees and 235 of them are NOT accountants. We can also solve the question by applying probability rules P(neither selection is an accountant) = P(1st selection is not an accountant AND 2nd selection is not an accountant) = P(1st selection is not an accountant) x P(2nd ...”
March 12, 2018
Brent@GMATPrepNow posted a reply to A jury pool consists of 6 men and w women. If 2 jurors are s in the Data Sufficiency forum
“Target question: Is P(2 men) greater than P(1 man and 1 woman)? Statement 1: w> 3 Let''s see what happens if w = 3 (note: this is the best chance that P(2 men) will be greater than P(1 man and 1 woman) P(2 men) = P(man selected 1st and man selected 2nd) = (6/9)(5/8) = 30/72 P(1 man ...”
March 12, 2018
Brent@GMATPrepNow posted a reply to How many times will the digit 7 be written when listing the 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 ...”
March 12, 2018
Brent@GMATPrepNow posted a reply to A and B ran, at their respective rates, a race of 480m... in the Problem Solving forum
“Here''s one approach. . . Let A = A''s speed in meters per second Let B = B''s speed in meters per second A gives B a head start of 48 m and beats him by 1/10th of a minute. 1/10th of a minute = 6 seconds A''s travel time is 6 seconds less than B''s travel time So, (A''s travel time) = ...”
March 12, 2018
Brent@GMATPrepNow posted a reply to If x + y > 0, is xy^2 + x^2y > 0? in the Data Sufficiency forum
“ Given: x + y > 0 Target question: Is xy² + x²y > 0 This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: Take the inequality: xy² + x²y > 0 Factor to get: xy(y + x)> 0 Since it is GIVEN ...”
March 12, 2018
Brent@GMATPrepNow posted a reply to A box contains one dozen donuts. Four of the donuts are... in the Problem Solving forum
“P(both are jelly) = P(1st selection is jelly AND 2nd selection is jelly) = P(1st selection is jelly) x P(2nd selection is jelly) = 4/12 x 3/11 = 1/11 Answer: A Cheers, Brent”
March 12, 2018
Brent@GMATPrepNow posted a reply to What is the value of the positive integer m? in the Data Sufficiency 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), ...”
March 12, 2018
Brent@GMATPrepNow posted a reply to Which of the following is a factor of 1001^32 -1 in the Problem Solving forum
“The key to answering this question is to recognize that 1001^32 − 1 is a difference of squares And so it 1001^16 - 1 And 1001^18 - 1 etc 1001^32 − 1 = (1001^16 + 1)(1001^16 - 1) = (1001^16 + 1)(1001^8 + 1)(1001^8 - 1) = (1001^16 + 1)(1001^8 + 1)(1001^4 + 1)(1001^4 - 1) = (1001^16 + ...”
March 9, 2018
Brent@GMATPrepNow posted a reply to If Q is a set of consecutive integers, what is the in the Data Sufficiency forum
“Target question: What is the standard deviation of Q? Given: Q is a set of CONSECUTIVE integers Statement 1: Set Q contains 21 terms. NOTE: Standard Deviation measures dispersion (spread-apart-ness). As such, the actual values mean nothing compared to RELATIVE values. For example, ...”
March 9, 2018
Brent@GMATPrepNow posted a reply to Unable to receive 60 days email GMAT prep plan in the The 60-Day GMAT Study Guide forum
“You might want to contact BTG’s main desk about this (maindesk@btgiforums.com) They are in charge of the Study Guide''s email program. Cheers, Brent”
March 9, 2018
Brent@GMATPrepNow posted a reply to If the average (arithmetic mean) of 3, 6, 10, m and n is 9, in the Problem Solving forum
“The average (arithmetic mean) of 3, 6, 10, m and n is 9 So, (3 + 6 + 10 + m + n)/5 = 9 Multiply both sides by 5 to get: 3 + 6 + 10 + m + n = 45 Simplify: 19 + m + n = 45 Subtract 19 from both sides to get: m + n = 26 What is the average of m + 4 and n – 2 ? We get: average = m + n + 2)/2 ...”
March 9, 2018
Brent@GMATPrepNow posted a reply to Is xy > 16? in the Data Sufficiency forum
“Target question: Is xy > 16? Statement 1: 1 < |x| < 4 Since there''s no information about y, we cannot determine whether xy is greater than 16 Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: y > 16 Since there''s no ...”
March 9, 2018
Brent@GMATPrepNow posted a reply to A soccer tournament is organized with 32 teams participating in the Problem Solving forum
“Fact #1: The tournament begins with 32 teams Fact #2: With each game played, 1 team leaves Fact #3: The tournament continues until only 1 team remains. So, if there are 31 games, there will be 31 teams that leave the tournament, leaving only 1 team (the winning team). Answer: D Cheers, ...”
March 8, 2018
Brent@GMATPrepNow posted a reply to For how many integer values of m is x < m < y in the Data Sufficiency forum
“Target question: For how many integer values of m is x < m < y ? Statement 1: x and y are positive integers There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = 3. In this case, only ONE value of m (m = 2) satisfies the inequality x < m ...”
March 8, 2018
Brent@GMATPrepNow posted a reply to If neither x nor y is divisible by 3, which of the following in the Problem Solving forum
“As it stands, all of the answer choices are correct. A. 333 If x = √300 and y = √33, then x² + y² = (√300)² + (√33)² = 300 + 33 = 333 B. 334 If x = √300 and y = √34, then x² + y² = (√300)² + (√34)² = 300 + 34 = 334 etc Cheers, Brent”
March 8, 2018
Brent@GMATPrepNow posted a reply to Quickest Way to do this GMAT Diagnostic Test Question in the Problem Solving forum
“The numbers are very spread apart (each answer choice is 10 times greater than the next answer choice). This means we can be quite AGGRESSIVE with our estimation. One approach: We have the product (2)(3)(5)(7)(11)(13)(17)(19) Let''s see if we can group the numbers to get some approximate ...”
March 8, 2018
Brent@GMATPrepNow posted a reply to 10! + 9! can be rewritten as: in the Problem Solving forum
“Once you''ve rewritten 10! + 9! as (11)9! and discovered that your answer is not among the answer choices, you can EITHER try to rewrite (11)9! so that it matches one of the answer choices, OR you can try to rewrite each answer choice so that it matches (11)9!. The second option is most likely the ...”
March 7, 2018
Brent@GMATPrepNow posted a reply to The number 75 can be written as the sum of the squares of... in the Problem Solving forum
“No, there''s no straightforward algebraic solution. Cheers, Brent”
March 7, 2018
Brent@GMATPrepNow posted a reply to The number 75 can be written as the sum of the squares of... in the Problem Solving forum
“We''re looking for 3 DIFFERENT squares that add to 75 Here are the only squares we need to consider: 1, 4, 9, 16, 25, 36, 49, 64 Can you find 3 that add to 75? After some fiddling, we may notice that 1 + 25 + 49 In other words, 1² + 5² + 7² = 75 We want the SUM of 1 + 5 + 7, which is ...”
March 7, 2018
Brent@GMATPrepNow posted a reply to In how many ways can a person post 5 letters in 3 letter box in the Problem Solving forum
“If that''s your final solution, then you appear to be treating the 5 letters as 5 IDENTICAL letters, and you are treating the 3 mailboxes as IDENTICAL mailboxes Cheers, Brent”
March 7, 2018
Brent@GMATPrepNow posted a reply to 10! + 9! can be rewritten as: in the Problem Solving forum
“You''re almost there! You have (11)9! Check the answer choice.....(11)9! isn''t there! So, we''ll need to check each answer choice. A. 9!(10) We can clearly see that this is not equal to (11)9! ELIMINATE A B. 11!/10 11!/10 = (11)(10)(9)(8)(7)(6)(5)(4)(3)(2)(1)/(10) = ...”
March 7, 2018
Brent@GMATPrepNow posted a reply to In how many ways can a person post 5 letters in 3 letter box in the Problem Solving forum
“IMPORTANT: The question doesn''t specify whether the letters and the letter boxes are UNIQUE, but I''m going to assume that they are unique. Take the task of distributing the 5 letters and break it into stages. Stage 1: Select a box for the 1st letter to go into. There are 3 available ...”
March 7, 2018
Brent@GMATPrepNow posted a reply to Pat, Kate and Marck charged a total of 162 hours of... in the Problem Solving forum
“We can also solve the question using one variable We can see that Kate charged the fewest hours, so... Let x =the number of hours Kate charged Pat charged twice as much time to the project as Kate So, 2x = the number of hours Pat charged Pat charged 1/3 as much times as Mark In other ...”
March 7, 2018
Brent@GMATPrepNow posted a reply to Which of the following fractions is greater than 1/4? in the Problem Solving forum
“A. 12/50 Notice that 12/48 = 1/4 So, 12/50 will be LESS THAN 1/4 Eliminate A B. 3/11 3/12 = 1/4 So, 3/11 will be GREATER THAN 1/4 Answer: B Cheers, Brent”
March 7, 2018
Brent@GMATPrepNow posted a reply to 2 men and 3 women can finish a piece of work in 10 days... in the Problem Solving forum
“We can solve this question using some common sense In fact, we don''t even need the information from the 2nd sentence (4 men can do it in 10 days. ) GIVEN: 2 men and 3 women can finish a piece of work in 10 days. How many days can 3 men and 3 women take to finish the same work? This new work ...”
March 6, 2018
Brent@GMATPrepNow posted a reply to OG 2018 CR Q Last year Comfort Airlines in the Critical Reasoning forum
“This is a paradox question. So, our first task is to identify the paradox (i.e., contradictory premises). The paradox is that the number of complaints TRIPLED even though the number of delayed flights only DOUBLED. All things considered equal, the number of complaints should have DOUBLED ...”
March 6, 2018
Brent@GMATPrepNow posted a reply to The largest of all the planets in the Sentence Correction forum
“Important: When a sentence begins with a with noun modifier, stop at the comma and ask the question that the modifier raises So, once we read, The largest of all the planets, we should stop and ask . . . "What is the largest of all the planets?" If the sentence is properly ...”
March 6, 2018
Brent@GMATPrepNow posted a reply to OG CR:Birds have been said to be descended in the Critical Reasoning forum
“This is an assumption question. PREMISE: Some believe that birds descended from dinosaurs PREMISE: There are bird fossils much older than the earliest birdlike dinosaur fossils found. CONCLUSION: Birds did NOT descend from birdlike dinosaurs First try to identify an assumption that the ...”
March 6, 2018
Brent@GMATPrepNow posted a reply to Comparison in the Sentence Correction forum
“The first part of this sentence sets up a comparison. When we get to the comma, we should STOP and ask the question that the introduction raises. So, once we read, In addition to having more protein than wheat does, we should stop and ask . . . "Who or what has more protein than ...”
March 6, 2018
Brent@GMATPrepNow posted a reply to In how many ways can a coach select a 4-person university te in the Data Sufficiency forum
“Target question: In how many ways can a coach select a 4-person university team from a pool of eligible candidates? This is a great candidate for rephrasing the target question. In order to determine the number of ways to select a 4-person university team, we need to know the number of ...”
March 6, 2018
Brent@GMATPrepNow posted a reply to Telephone Company X's monthly charge for long-distance telep in the Problem Solving forum
“Let x = the total number of minutes of long-distance calls Telephone Company X''s monthly charge for long-distance telephone calls is $1.95 plus$0.10 per minute So, TOTAL charge = $1.95 +$0.10(x) Telephone Company Y''s monthly charge is $5.95 plus$0.08 per minute TOTAL charge = $5.95 + ...” March 6, 2018 Brent@GMATPrepNow posted a reply to What is the tens digit of the number r? in the Data Sufficiency forum “Target question: What is the tens digit of the positive integer r? Given: r is a positive integer Statement 1: The tens digit of r/10 is 3 Since r is an INTEGER, 10/r will have 1 digit to the right of the decimal place. So, r/10 = ????3?.? Multiply both sides by 10 to get: r = ...” March 6, 2018 Brent@GMATPrepNow posted a reply to 10 members of a society, including members A and B, attended in the Problem Solving forum “Let''s apply some probability rules P(A and B both selected) = P(1st selection is one member of the pair AND 2nd selection is the other member of the pair) = P(1st selection is one one member of the pair) x P(2nd selection is the other member of the pair) = 2/10 x 1/9 = 1/45 Answer: E ...” March 6, 2018 Brent@GMATPrepNow posted a reply to Using Double Matrix method--Felixity, a musician, never sing in the Data Sufficiency forum “I thought I''d point out that Mitch''s Double Matrix 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 songs, and the two characteristics are: - sad or not sad - rock or not rock ...” March 5, 2018 Brent@GMATPrepNow posted a reply to A magician has five animals in his magic hat in the Problem Solving forum “We can also solve the question using counting methods To begin, P(matched pair) = (# of ways to get a matched pair)/(# of ways to select 2 animals) As always, begin with the denominator. # of ways to select 2 animals To count this, we''ll treat each animal as different. We''ll take the ...” March 5, 2018 Brent@GMATPrepNow posted a reply to A magician has five animals in his magic hat in the Problem Solving forum “One approach is to apply probability rules First notice that, to get a matched pair, we can select 2 doves or 2 rabbits. So, P(matched pair) = P(1st pick is rabbit AND 2nd pick is rabbit OR 1st pick is dove AND 2nd pick is dove) We can now apply our AND and OR rules to get: P(matched ...” March 5, 2018 Brent@GMATPrepNow posted a reply to A certain road trip was completed in two parts... in the Problem Solving forum “Let''s start with a word equation (distance traveled during FIRST part of trip) + (distance traveled during SECOND part of trip) = 480 miles Let t = time spend on FIRST part of trip (in hours) So, 8-t = time spend on SECOND part of trip (since the ENTIRE driving time was 8 hour) Distance = ...” March 5, 2018 Brent@GMATPrepNow posted a reply to Running at their respective constant rates, machine X takes in the Problem Solving forum “Another approach is to assign a nice value to the job (w) Let''s say that w = 12. GIVEN: Running at their respective constant rates, machine X takes 2 days longer to produce 12 widgets than machine Y Let t = time for machine Y to produce 12 widgets So, t+2 = time for machine X to produce ...” March 5, 2018 Brent@GMATPrepNow posted a reply to An empty pool being filled with water at a constant rate in the Problem Solving forum “Here''s another approach: IMPORTANT CONCEPT: After 8 hours, 3/5 of the job is finished and 2/5 of the job is remaining. This means the remaining part of the job is 2/3 the size of the first part of the job. Think of it this way: If the pool had a capacity of 5 gallons, then the first part ...” March 5, 2018 Brent@GMATPrepNow posted a reply to Is x divisible by 3? in the Data Sufficiency forum “For the answer to be C, we need some sort of restriction that states x and y are integers. Otherwise, non-integer pairs of values such as x = 4.5 and y = 1.5 satisfy both statements. Cheers, Brent” March 5, 2018 Brent@GMATPrepNow posted a reply to Bruce and Anne can clean their house in 4 hours working... in the Problem Solving forum “Another approach is to assign a NICE value to the job. We''ll choose a value that works well with the given information (4 hours and 3 hours) So let''s say the cleaning job consists of cleaning 12 rooms Let A = the number of rooms that Anne can clean in ONE hour Let B = the number of rooms ...” March 4, 2018 Brent@GMATPrepNow posted a reply to If it is true that z < 8 and 2z > -4, which of the fol in the Problem Solving forum “Hi LUANDATO, Your conclusion, -2 < z < 8, is perfect. So, if z is BETWEEN -2 and 8, then z must be greater than -8 Answer: C Cheers, Brent” March 4, 2018 Brent@GMATPrepNow posted a reply to If it is true that z < 8 and 2z > -4, which of the fol in the Problem Solving forum “Hi LUANDATO, Your conclusion, -2 < z < 8, is perfect. So, if z is BETWEEN -2 and 8, then z must be greater than -8 Answer: C Cheers, Brent” March 4, 2018 Brent@GMATPrepNow posted a reply to function above x-axis? in the Data Sufficiency forum “This is way beyond the scope of the GMAT. Cheers, Brent” March 4, 2018 Brent@GMATPrepNow posted a reply to Alex paid a$12 fee to receive a 10% discount off 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 ...”
March 4, 2018
Brent@GMATPrepNow posted a reply to If A, B, C, and D are integers such that A - C + B is even a in the Problem Solving forum
“Given: A - C + B = EVEN and D + B - A = ODD Add them to get: (A - C + B) + (D + B - A) = EVEN + ODD Simplify: 2B + D - C = ODD Since 2B is ALWAYS even, we get: EVEN + D - C = ODD So: D - C = ODD - EVEN This means: D - C = ODD If D - C is ODD, then we know that one of the numbers is EVEN and ...”
March 3, 2018
Brent@GMATPrepNow posted a reply to When a cylindrical tank is filled with water... in the Problem Solving forum
“Let''s examine what occurs in a 1-hour period The volume of water increases by 22 cubic meters. The height of the water increases by 0.7 meters. So, we need to find the radius of a 0.7 meter high cylinder that has a volume of 22 cubic meters. Volume = (pi)r²h 22 = (pi)r²(0.7) ...”
March 2, 2018
Brent@GMATPrepNow posted a reply to The sum of 5 different positive 2-digit integers is 130. in the Problem Solving forum
“Since the 5 numbers are all different, let''s let A, B, C, D and E represent the numbers. Furthermore, let''s say A < B < C , D < E, which means E is the biggest value. We''re told that A + B + C + D + E = 130 In order to MAXIMIZE the value of E, we must MINIMIZE the other 4 values. ...”
March 2, 2018
Brent@GMATPrepNow posted a reply to A company that ships boxes to a total of 12 distribution in the Problem Solving forum
“We need to be able to create AT LEAST 12 codes (to represent the 12 countries). Let''s test the options. Can we get 12 or more color codes with 4 colors? Let''s see . . . 1-color codes = 4 (since there are 4 colors) 2-color codes = We need to choose 2 colors from 4. This can be ...”
March 2, 2018
Brent@GMATPrepNow posted a reply to John would have reduced the time it took him to drive in the Problem Solving forum
“Let''s start with a word equation: (John''s travel time at faster speed) = 2/3(John''s regular travel time) Let r = John''s regular speed So, r+15 = John''s faster speed Let d = the distance traveled at regular speed So d = the distance traveled at regular speed time = distance/speed ...”
March 2, 2018
Brent@GMATPrepNow posted a reply to John traveled the entire 50 km trip. If he travelled the fir in the Problem Solving forum
“Average speed = total distance/total travel time total distance = 50 km total travel time = time spent driving at 40 kmh + time spent driving at 20 kmh time = distance/speed So, time spent driving at 40 kmh = 20/40 = 1/2 hour And time spent driving at 20 kmh = 30/20 = 3/2 hours So, TOTAL ...”
March 2, 2018
Brent@GMATPrepNow posted a reply to Is x > 0 ? in the Data Sufficiency forum
“Target question: Is x > 0 ? (i.e., is x POSITIVE?) Statement 1: x < x² This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of x that satisfy statement 1. Here are two: Case a: x = -0.5 (notice that (-0.5)² = 0.25, so this meets the condition ...”
March 1, 2018
Brent@GMATPrepNow posted a reply to When n is divided by 5, what is the remainder? in the Data Sufficiency forum
“Target question: When n is divided by 5, what is the remainder? Statement 1: When n is divided by 3, the remainder is 2 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. ...”
March 1, 2018
Brent@GMATPrepNow posted a reply to Which of the following is equivalent to √3+√2? in the Problem Solving forum
“Nice question! KEY CONCEPT: If we take a positive number, square it and then take the square root of the result, we''ll get back to the same number we started with. For example... Take: 5 Square it to get: 25 Take the square root: √25 Evaluate: 5 Now let''s answer the question: ...”
March 1, 2018
Brent@GMATPrepNow posted a reply to If m, p, and t are distinct positive prime numbers 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 = ...”
March 1, 2018
Brent@GMATPrepNow posted a reply to If the product of the integers a, b, c, and d is 1,155. . . in the Problem Solving forum
“This question calls for some prime factorization 1,155 = (3)(5)(7)(11) Since 1 < d < c < b < a, we can conclude that d = 3, c = 5, b = 7 and a = 11 So, a - d = 11 - 3 = 8. Answer: B Cheers, Brent”
March 1, 2018
Brent@GMATPrepNow posted a reply to Which of the following are/is prime? in the Problem Solving forum
“I. 143 143 = 11 x 13 So, 143 is NOT prime. ELIMINATE C, D and E II. 147 Check the sum of the digits. 1+4+7 = 12 Since 12 is divisible by 3, we know that 147 is divisible by 3 So, 147 is NOT prime. ELIMINATE A By the process of elimination, the correct answer is B Cheers, Brent”
March 1, 2018
Brent@GMATPrepNow posted a reply to When x/y = 2.6, (x-y)/(x+y)=? in the Problem Solving forum
“GIVEN: x/y = 2.6 Scan the answer choices.... All of them are in fraction form. So.... Rewrite 2.6 as a fraction: x/y = 2 3/5 Or...: x/y = 13/5 So, let''s let x = 13 and y = 5, since these values satisfy the condition that x/y = 13/5 Our goal is to find the value of (x - y)/(x + y) Plug in ...”
February 28, 2018
Brent@GMATPrepNow posted a reply to If p is an even integer and q is an odd integer in the Problem Solving forum
“Another approach is to take each answer choice and plug in an even number for p and an odd number for q, and see which answer choices yield an ODD value. The easiest numbers to test are p = 0 (which is EVEN) and q = 1 (which is ODD) We get: A. p/q = 0/1 = 0, which is EVEN. ELIMINATE A B. pq ...”
February 28, 2018
Brent@GMATPrepNow posted a reply to The ratio of local and international calls made by Amy... in the Problem Solving forum
“Let L = number of local calls made this week Let N = number of international calls made this week The ratio of local and international calls made by Amy this week is 5 to 2 So, L/N = 5/2 Cross multiply to get: 2L = 5N The ratio changes to 5 to 3 after Amy makes three more international ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to speed/distance in the Problem Solving forum
“Let''s start with a word equation Distance traveled at 3/4 speed = Distance traveled at regular speed Let v = regular walking speed (in miles/minute) So, 3v/4 = REDUCED walking speed (in miles/minute) Let t = regular travel time (in minutes) So, t + 16 = travel time (in minutes) when ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to combinatorics problem in the Problem Solving forum
“We need to be able to create AT LEAST 12 codes (to represent the 12 countries). Let''s test the options. Can we get 12 or more color codes with 4 colors? Let''s see . . . 1-color codes = 4 (since there are 4 colors) 2-color codes = We need to choose 2 colors from 4. This can be ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to Find the area of the shaded region. in the Problem Solving forum
“Area of shaded region = (area of sector) - (area of triangle) Area of circle = π(radius)² Area of triangle = (base)(height)/2 The sector ABC is 1/4 of a circle of radius 8 So, area of sector = (1/4)(π)(8²) = 16π area of triangle = (8)(8)/2 = 32 So, area of shaded region = ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to The cost per pound of tea and coffee were the same in June. in the Problem Solving forum
“Let''s continue where you left off: Let x = price (PER POUND) of tea in JUNE So, Let x = price (PER POUND) of coffee in JUNE Price of tea (PER POUND) in JULY = 0.1x (decrease by 90%). Price of coffee (PER POUND) in JULY = 3x (increase by 200%). In July, a mixture containing equal ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to What is the number of factors of a positive integer n? in the Data Sufficiency forum
“Target question: What is the number of factors of a positive integer n? Statement 1: n is a multiple of 7 There are several values of n that satisfy statement 1. Here are two: Case a: n = 7. In this case, n has TWO factors (1 and 7) Case b: n = 7. In this case, n has FOUR factors (1, 2, 7 ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to The number of boxes in a warehouse can be divided evenly... in the Problem Solving forum
“Let N = the number of boxes in the warehouse If the boxes in a warehouse can be divided evenly into 6 equal shipments (by boat), then N is divisible by 6 If the boxes in a warehouse can be divided evenly into 27 equal shipments (by truck), then N is divisible by 27 What is the smallest number ...”
February 27, 2018
Brent@GMATPrepNow posted a reply to A physics class has majors and non-majors in a ratio of... in the Problem Solving forum
“The ratio of the number of physics majors to non-physics majors is 3 to 5 Let P = number of Physics majors Let N = number of Non-physics majors So, we get: P/N = 3/5 Cross multiply to get: 5P = 3N Rearrange to get: 5P - 3N = 0 If two of the physics majors were to change their major to ...”
February 26, 2018
Brent@GMATPrepNow posted a reply to Alice's take-home pay last year was the same each month... 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 ...” February 26, 2018 Brent@GMATPrepNow posted a reply to If n and p are positive integers, what is the ratio of in the Data Sufficiency forum “Target question: What is the ratio of n to p? Given: n and p are positive integers Statement 1: np = 48 This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of n and p that satisfy statement 1. Here are two: Case a: n = 1 and p = 48. In this ...” February 26, 2018 Brent@GMATPrepNow posted a reply to OG City X has a population 4 times in the Problem Solving forum “One approach is to assign some values that meet the given information City Y has a population twice as great as the population of City Z Let''s say the population of City Z is 1 person This means the population of City Y is 2 people City X has a population 4 times as great as the population ...” February 26, 2018 Brent@GMATPrepNow posted a reply to Is x > y ? in the Data Sufficiency forum “Target question: Is x > y ? Statement 1: ax > ay WARNING: Some students will divide both sides by a and incorrectly conclude that x > y. However, before we divide by a variable, we must ensure that the variable is EITHER positive OR negative, because if we divide by a negative ...” February 26, 2018 Brent@GMATPrepNow posted a reply to A box contains a total of 56 balls of red and blue color in the Problem Solving forum “As Rich has shown, the box ORIGINALLY has 21 RED balls and 35 BLUE balls. Let x = number of RED balls to be removed from the box. Once we remove x RED balls, there are 21-x RED balls and 35 BLUE balls. We want the ratio of red and blue balls to be less than 2 to 7 So, we want: 21-x /35 ...” February 26, 2018 Brent@GMATPrepNow posted a reply to Leon, Billy, and Jim ate an astounding total of 78 hot... in the Problem Solving forum “Let x = # of hot dogs that Jim ate Jim ate four times as many hot dogs as Leon In other words, Leon ate 1/4 as many hot dogs as Jim ate So, x/4 = # of hot dogs that Leon ate Jim ate half as many hot dogs as Billy In other words, Billy ate twice as many hot dogs as Jim ate So, 2x = # of ...” February 26, 2018 Brent@GMATPrepNow posted a reply to Agela 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, ...” February 26, 2018 Brent@GMATPrepNow posted a reply to The function f(n) = the number of factors of n. If p and q a in the Data Sufficiency forum “Target question: What is the value of p? Given: f(n) = the number of factors of n. If p and q are positive integers and f(pq) = 4 IMPORTANT: Notice that the product pq will be sure to have AT LEAST 4 factors. If p and q are PRIME numbers, then the product pq has the following factors: 1, ...” February 25, 2018 Brent@GMATPrepNow posted a reply to What could be the range of a set consisting of odd multiples in the Problem Solving forum “We could just test numbers. 7, 21 and 77 are odd multiples of 7. The range of these numbers = 77 - 7 = 70 Answer: E Cheers, Brent” February 25, 2018 Brent@GMATPrepNow posted a reply to what is the value of m? in the Data Sufficiency forum “Target question: What is the value of m? Statement 1: 5 is a factor of m There are several values of m that satisfy statement 1. Here are two: Case a: m = 5 Case b: m = 10 Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: m is a ...” February 24, 2018 Brent@GMATPrepNow posted a reply to What is the best method to crack reading passage in the Reading Comprehension forum “I suggest that you read the passage at a regular speed and take notes while doing so. Namely, you should identify and summarize: - the theme of each paragraph (4 to 8 words) - conflicting points of view (4 to 8 words) - main idea (4 to 8 words) So, we''re talking about 20 to 30 words ...” February 24, 2018 Brent@GMATPrepNow posted a reply to Kevin buys beer in bottles and cans. He pays$1.00 in the Data Sufficiency forum
“Target question: How many bottles of beer did Kevin buy? Given: Kevin pays $1.00 for each can of beer and$1.50 for each bottle of beer. Kevin buys a total of 15 bottles and cans of beer Let C = the NUMBER of Cans that Kevin bought Let B = the NUMBER of Bottles that Kevin bought So, we can ...”
February 24, 2018
Brent@GMATPrepNow posted a reply to If 1 > 1 - ab > 0, which of the following must be true in the Problem Solving forum
“GIVEN: 1 > 1 - ab > 0 Multiply all 3 sides by -1 to get: -1 < -1 + ab < 0 Add 1 to all 3 sides to get: 0 < ab < 1 First, if 0 < ab, then a and b are the SAME SIGN, which means a/b > 0 So, statement I is TRUE ELIMINATE B and C Second, our new inequality clearly ...”
February 24, 2018
Brent@GMATPrepNow posted a reply to Liz drove from point A to point B at 40km/h. On her way back in the Problem Solving forum
“Hi AAPL, Your solution is perfect. Cheers, Brent”
February 24, 2018
Brent@GMATPrepNow posted a reply to Liz drove from point A to point B at 40km/h. On her way back in the Problem Solving forum
“Let''s start with a word equation travel time at 40 kmh = travel time at 50 kmh + 1 hour time = distances/speed Let d = the distance from A to B So, we get: d/40 = d/50 + 1 Multiply both sides by 200 to get: 5d = 4d + 200 Solve: d = 200 Answer: B Cheers, Brent”
February 24, 2018
Brent@GMATPrepNow posted a reply to If |x|=−x, which of the following must be true? in the Problem Solving forum
“We know that |x| is always greater than or equal to zero So, if |x| = -x, then we can be certain that -x is greater than or equal to zero In other words, -x ≥0 To solve for x, multiply both sides of the inequality by -1 to get: x ≤0 Answer: B Cheers, Brent”
February 24, 2018
Brent@GMATPrepNow posted a reply to Retailers question in the Data Sufficiency forum
“I thought I''d point out that Ceilidh''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 students, and the two characteristics are: - owns store or doesn''t own store - ...”
February 23, 2018
Brent@GMATPrepNow posted a reply to Malik's recipe for 4 servings of a certain dish requires 3/2 in the Data Sufficiency forum
“Target question: How many cups of pasta will Malik use the next time he prepares this dish? Given: 4 servings of a certain dish requires 1 1/2 cups of pasta. So, if we can determine the NUMBER OF DISH SERVINGS Malik prepares, we can determine how much past is required. Statement 1: The ...”
February 23, 2018
Brent@GMATPrepNow posted a reply to Runners V, W, X, Y, and Z are competing in the Bayville loca in the Problem Solving forum
“Another option is to systematically list and count the possible outcomes To begin, Z, W and V must have the following order: Z-W-V Now insert an X and a Y so that X is ahead of Y. We get: 1) YZWVX 2) ZYWVX 3) ZWYVX 4) ZWVYX 5) YZWXV 6) ZYWXV 7) ZWYXV 8) YZXWV 9) ZYXWV 10) YXZWV ...”
February 22, 2018
Brent@GMATPrepNow posted a reply to Runners V, W, X, Y, and Z are competing in the Bayville loca in the Problem Solving forum
“Take the task of arranging the 5 runners and break it into stages. GIVEN: V finishes before W and W finishes before Z So, the order is: Z - W - V Our goal is to now place the remaining 2 runners (runner X and runner Y) NOTE: I''m going to IGNORE the restriction that says X must finish ...”
February 22, 2018
Brent@GMATPrepNow posted a reply to Eight dogs are in a pen when the owner comes to walk some in the Problem Solving forum
“Take the task of arranging the 5 dogs in a line and break it into stages. Stage 1: Select a dog to be 1st in the line There are 8 dogs to choose from, so, we can complete stage 1 in 8 ways Stage 2: Select a dog to be 2nd in the line There are 7 remaining dogs from which to choose, so we ...”
February 22, 2018
Brent@GMATPrepNow posted a reply to If Carla, Nora, and Wanda have a total of $48, how much in the Data Sufficiency forum “Target question: How much money does Carla have? Given: Carla, Nora, and Wanda have a total of$48 Statement 1: The positive difference between the amounts of money that Carla and Nora have is $12. Since we have no information about Wanda, there''s no way to use this information to ...” February 22, 2018 Brent@GMATPrepNow posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum “I was going to use some values for x and y to ELIMINATE A, B, C and E, but then realized that E is also correct (unless I''m missing something obvious). If we CAN find values for x and y in which an answer choice IS the LCM of x and y, then we can ELIMINATE that answer choice. (A) xy. If x = ...” February 22, 2018 Brent@GMATPrepNow posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum “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 always greater than or equal to N Answer choice D (x - y), suggests that x-y is a multiple of x ...” February 22, 2018 Brent@GMATPrepNow posted a reply to Gina and Tina's average grade is 23 points higher than... in the Problem Solving forum “Your solution is perfect, AAPL! Cheers, Brent” February 22, 2018 Brent@GMATPrepNow posted a reply to Is v - w > x - y in the Data Sufficiency forum “This is a question from our course. Here''s the video solution: https://www.gmatprepnow.com/module/gmat-algebra-and-equation-solving/video/984 Cheers, Brent” February 21, 2018 Brent@GMATPrepNow posted a reply to What is the greatest prime factor of 8^12 - 2^30? in the Problem Solving forum “To determine the greatest prime factor of 8^12 - 2^30, we must find the prime factorization of 8^12 - 2^30 Given: 8^12 - 2^30 Rewrite 8 as 2³ to get: (2³)^12 - 2^30 Apply Power of Power rule to get: 2^36 - 2^30 Factor out 2^30 to get: 2^30(2^6 - 1) Evaluate: 2^30(64- 1) Simplify: 2^30(63) ...” February 21, 2018 Brent@GMATPrepNow posted a reply to Z is 120% of Y. X is smaller than Z by 80%. What percentage in the Problem Solving forum “Your algebraic solution is perfect. Cheers, Brent” February 21, 2018 Brent@GMATPrepNow posted a reply to Z is 120% of Y. X is smaller than Z by 80%. What percentage in the Problem Solving forum “We can also solve this by assigning values that meet the given conditions. Z is 120% of Y So, let Z = 120 and let Y = 100 X is smaller than Z by 80%. In other words, X is 20% of Z If Z = 120, then X = 20% of 120 So, X = 24 What percentage is X of Y? 24/100 = 24% Answer: E ...” February 21, 2018 Brent@GMATPrepNow posted a reply to A worker can load 1 full truck in 6 hours. A second worker.. in the Problem Solving forum “One approach is to assign a nice value to the entire job (of filling a truck) We want a number that works well with the given times (6 hours and 7 hours) 42 is such a number. So, let''s say that filling the truck is equivalent to shoveling 42 scoops of dirt into it. A worker (we''ll call ...” February 21, 2018 Brent@GMATPrepNow posted a reply to The lengths of two sides of a certain triangle are 3 and 9. in the Data Sufficiency forum “Target question: What is the length of the 3rd side of the triangle? Given: The other two sides have lengths 3 and 9 Statement 1: The perimeter of the triangle is 20 Let x = the length of the third side If the perimeter is 20, we can write: 3 + 9 + x = 20 Solve to get: x = 8 So, the ...” February 19, 2018 Brent@GMATPrepNow posted a reply to At the beginning of a class, a classroom has 3 empty chairs in the Problem Solving forum “Let N = the number of seated students ORIGINALLY in the class We''re told that the LATE student fill the 3 remaining seats. So, there are 3 LATE students We''re also told that number of LATE students = 20 percent of the number of students already seated In other words: number of LATE ...” February 19, 2018 Brent@GMATPrepNow posted a reply to A standardized multiple-choice exam has 60 questions in the Problem Solving forum “Take the task of completing the test and break it into stages. Stage 1: Answer question #1 Since their are 5 answer choices, we can complete stage 1 in 5 ways Stage 2: Answer question #2 Since their are 5 answer choices, we can complete stage 2 in 5 ways Stage 3: Answer question #3 ...” February 19, 2018 Brent@GMATPrepNow posted a reply to If the 3rd term in a sequence in the Problem Solving forum “This is not a GMAT-worthy question. What''s the source? We have no information about this sequence to help us be certain of the value of the 87th term. In fact, the sequence COULD be as follows: 25, -3, 25, -3, 25, -3, 25, -3, 25, -3,.... In this case, the 87th term is 25 (not among the ...” February 18, 2018 Brent@GMATPrepNow posted a reply to The number 75 can be written as the sum in the Problem Solving forum “We''re looking for 3 DIFFERENT squares that add to 75 Here are the only squares we need to consider: 1, 4, 9, 16, 25, 36, 49, 64 Can you find 3 that add to 75? After some fiddling, we may notice that 1 + 25 + 49 In other words, 1² + 5² + 7² = 75 We want the SUM of 1 + 5 + 7, which is ...” February 17, 2018 Brent@GMATPrepNow posted a reply to What is the perimeter of a rectangle if the ratio of its wid in the Data Sufficiency forum “Target question: What is the perimeter of the rectangle? Given: Ratio of its width to its length is 3 to 4? Let W = width of the rectangle Let L = length of the rectangle We can write: W/L = 3/4 Statement 1: The width of the rectangle is 6 If the width = 6, we can write: 6/L = 3/4 ...” February 17, 2018 Brent@GMATPrepNow posted a reply to If x is an integer, is x between 27 and 54? in the Data Sufficiency forum “Target question: Is x between 27 and 54? ASIDE: 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 ...” February 17, 2018 Brent@GMATPrepNow posted a reply to Which of the following best approximates in the Problem Solving forum “Another approach: (0.2)(0.3)(0.4)(0.5) = (2/10)(3/10)(4/10)(5/10) = 120/10000 = 12/1000 ASIDE: Notice that 12/1000 is pretty close to 10/1000 10/1000 = 1/100 = 0.01 So, 12/1000 is closest to 0.01 Cheers, Brent” February 17, 2018 Brent@GMATPrepNow posted a reply to In how many ways can the letters of word "EDUCATION&quo in the Problem Solving forum “VOWELS: E, U, A, I, O CONSONANTS: D, C, T, N Take the task of arranging the letters and break it into stages. Stage 1: Arrange the 5 vowels We can arrange n unique objects in n! ways So, we can arrange the 5 vowels in 5! ways In other words, we can complete stage 1 in 5! ways Stage ...” February 17, 2018 Brent@GMATPrepNow posted a reply to If Tom goes y miles in x hours, how many miles does he go in the Problem Solving forum “x hours = 60x MINUTES (since there are 60 minutes in each hour) So, the DISTANCE Tom travels = y miles, and his TRAVEL TIME = 60x minutes Speed = distance/time So, Tom''s speed = y/(60x) Answer: B Cheers, Brent” February 17, 2018 Brent@GMATPrepNow posted a reply to Which of the following inequalities in the Problem Solving forum “We know that, if |something| < b (when b is positive), then -b < something < b For example, if |2x+1| < 5 , then -b < 2x+1 < 5 We''re going to apply the above rule IN REVERSE Given: –2 < x < 4 Subtract 1 from all parts: -3 < x-1 < 3 So: |x-1| < 3 ...” February 14, 2018 Brent@GMATPrepNow posted a reply to If 5n/(4n - x) = (0.788)^(-1) , then x/n = in the Problem Solving forum “I created this question to test a certain fraction property that the GMAT likes to test: (a - b)/c = a/c - b/c There''s also (a + b)/c = a/c + b/c Given: 5n/(4n - x) = (0.788)^(-1) Rewrite as: 5n/(4n - x) = 1/0.788 Flip each fraction: (4n-x)/5n = 0.788 Apply above property: 4n/5n - x/5n = ...” February 14, 2018 Brent@GMATPrepNow posted a reply to If 2^{(x+y)^2} / 2^{(x-y)^2} = 2, what is the value of xy? in the Problem Solving forum “(x + y)² = x² + 2xy + y² (x - y)² = x² - 2xy + y² Given: 2^(x + y)²/2^(x - y)² = 2 Expand both exponents to get: 2^(x² + 2xy + y²)/2^(x² - 2xy + y²) = 2 Apply Quotient Law to get: 2^(4xy) = 2 In other words, 2^(4xy) = 2^1 This means that: 4xy = 1 Divide both sides by 4 to get: ...” February 13, 2018 Brent@GMATPrepNow posted a new topic called If 5n/(4n - x) = (0.788)^(-1) , then x/n = in the Problem Solving forum “If 5n/(4n - x) = (0.788)^(-1) , then x/n = A) 3/500 B) 3/250 C) 3/125 D) 3/50 E) 3/25 Source: www.gmatprepnow.com Answer: D Difficulty level: 650 - 700” February 13, 2018 Brent@GMATPrepNow posted a reply to When a person aged 39 is added to a group of n people in the Problem Solving forum “One more solution: Let m = mean of ORIGINAL n people This means the SUM of the ages of the ORIGINAL n people = nm When a person aged 39 is added to a group of n people, the average age increases by 2 In other words: new mean (with extra person) of n+1 people = original mean + 2 Rewrite as: ...” February 13, 2018 Brent@GMATPrepNow posted a reply to Tricky Inequalities in the Problem Solving forum “First, let''s deal with the given inequality. 4 < (7-x)/3 Multiply both sides by 3 to get: 12 < 7 - x Add x to both sides: x + 12 < 7 Subtract 12 from both sides to get: x < -5 So, if x < -5, which of the following statements MUST be true? Aside: When dealing with ...” February 13, 2018 Brent@GMATPrepNow posted a reply to x percent of what number is equal to y in the Data Sufficiency forum “Target question: x percent of what number is equal to y? This is a good candidate for rephrasing the target question x percent of what number is equal to y? Let k = the number we''re trying to determine We get: "If x percent of k is equal to y, what is the value of k? In other words, ...” February 12, 2018 Brent@GMATPrepNow posted a reply to Jennifer has 60 dollars more than Brian. If she were to in the Problem Solving forum “Here''s one approach: Let J = Jennifer''s$ Let B = Brian''s $Jennifer has 60 dollars more than Brian. So, J = B + 60 If Jennifer were to give Brian 1/5 of her money, Brian would have 25% less than the amount that Jennifer would then have. If Jennifer were to give Brian 1/5 of her ...” February 11, 2018 Brent@GMATPrepNow posted a reply to At a certain hotel in the Data Sufficiency forum “Here''s our video solution for that question: https://www.gmatprepnow.com/module/gmat-word-problems/video/943 Cheers, Brent” February 11, 2018 Brent@GMATPrepNow posted a reply to If x is divided by 7, the remainder is 5. What is the 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), ...” February 10, 2018 Brent@GMATPrepNow posted a reply to When a certain number X is divided 63, the remainder... 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), ...” February 10, 2018 Brent@GMATPrepNow posted a reply to Problem Solving in the Problem Solving forum “Here''s an algebraic solution: Let d = the TOTAL distance to school. Bob had a flat tire exactly halfway to school So, d/2 = distance spent biking and d/2 = distance spent walking We can write: (time spent biking) + (time spent walking) = t time = distance/speed We get: (d/2)/x + ...” February 10, 2018 Brent@GMATPrepNow posted a reply to If x and y are positive integers such that y is a multiple o in the Problem Solving forum “If y is a multiple of 5, then we know that y = 5k for some integer k. So, let''s take 3x + 4y = 200 and replace y with 5k to get: 3x + 4(5k) = 200 Simplify to get: 3x + 20k = 200 (where k is some integer) Subtract 20k from both sides to get: 3x = 200 - 20k Divide both sides by 3 to get: x = (200 ...” February 10, 2018 Brent@GMATPrepNow posted a reply to What is the perimeter of quadrilateral Q? in the Data Sufficiency forum “Target question: What is the perimeter of quadrilateral Q? If we recognize that each statement alone is not sufficient, we can jump straight to...... Statements 1 and 2 combined There are several quadrilaterals satisfy BOTH statements. Here are two: Case a: Q is a rectangle with width 1 ...” February 10, 2018 Brent@GMATPrepNow posted a reply to Walking at 60% of his usual speed a man takes... in the Problem Solving forum “Let''s start with a WORD EQUATION: distance traveled at REGULAR speed = distance traveled at REDUCED speed distance = (rate)(time) Let R = REGULAR speed So 0.6R = REDUCED speed Let t = travel time (in minutes) at REGULAR speed So t + 24 = travel time (in minutes) at REDUCED speed Now ...” February 9, 2018 Brent@GMATPrepNow posted a reply to What is the perimeter of quadrilateral Q in the Data Sufficiency forum “Target question: What is the perimeter of quadrilateral Q? If we recognize that each statement alone is not sufficient, we can jump straight to...... Statements 1 and 2 combined There are several quadrilaterals satisfy BOTH statements. Here are two: Case a: Q is a rectangle with width 1 ...” February 9, 2018 February 8, 2018 Brent@GMATPrepNow posted a reply to Set K consists of a finite number of consecutive in the Data Sufficiency forum “Target question: What is the value of y - x? Given: Set K consists of a finite number of consecutive odd integers Statement 1: The average (arithmetic mean) of set K is –36 There''s a nice rule that says, "In a set where the numbers are equally spaced, the mean will equal the ...” February 8, 2018 Brent@GMATPrepNow posted a reply to If a > b > c > 0, is c < 3 ? in the Data Sufficiency forum “Target question: Is c < 3? Given: 0 < c < b < a Statement 1: 1/a > 1/3 Since we can be certain that a is positive, it''s safe to take the inequality 1/a > 1/3 and multiply both sides by a to get: 1 > a/3 Likewise, we can take 1 > a/3 and multiply both sides by 3 ...” February 8, 2018 Brent@GMATPrepNow posted a reply to On a 20 mile course, Pat bicycled at an average rate of 30 in the Problem Solving forum “Let''s start with a WORD EQUATION (Distance traveled at 30 mph) + (Distance traveled at 8 mph) = 20 miles Distance = (rate)(time) Let t = the time (in hours) Pat spent running at 8 mph Aside: 12 minutes = 1/5 hours So, we get: (30 miles per hour)(1/5 hours) + (8 miles per hour)(t ...” February 8, 2018 Brent@GMATPrepNow posted a reply to Is a positive? in the Data Sufficiency forum “Target question: Is a positive? Statement 1: a - b > 0 This statement doesn''t FEEL sufficient, so I''ll TEST some values. There are several values of a and b that satisfy statement 1. Here are two: Case a: a = 5 and b = 1. In this case, the answer to the target question is YES, a IS ...” February 8, 2018 Brent@GMATPrepNow posted a reply to How many odd numbers between 10 and 1,000 in the Problem Solving forum “First notice (ODD number)² = ODD number And (EVEN number)² = EVEN number So, we''re looking for the squares of ODD integers that are between 10 and 1000 The first integer that works is 25 (since 5² = 25) The next integer is 49 (since 7² = 49) The next integer is 81 (since 9² = 81) . ...” February 8, 2018 Brent@GMATPrepNow posted a reply to A helicopter company charges$85 for the first kilometer... in the Problem Solving forum
“Perfect approach! Cheers, Brent”
February 8, 2018
Brent@GMATPrepNow posted a reply to The number of baseball cards that John and Bill... in the Problem Solving forum
“One option is to solve the question using 2 variables Let J = # of cards that John INITIALLY had Let B = # of cards that Bill INITIALLY had The number of baseball cards that John and Bill had was in the ratio of 7:3 So, we can write: J/B = 7/3 Cross multiply to get: 3J = 7B Rearrange to ...”
February 8, 2018
Brent@GMATPrepNow posted a reply to Rhonda runs at an average speed of 12 kilometers per hour, a in the Problem Solving forum
“When Rhonda bicycles to work, her travel time is 2.25 minutes less than when she runs to work It might be useful to start with a Word Equation (Rhonda''s running time in hours) = (Rhonda''s cycling time in hours) + 2.25/60 hours Aside: 2.25 minutes = 2.25/60 hours travel time = distance/speed ...”
February 7, 2018
Brent@GMATPrepNow posted a reply to What is the range of 29 consecutive even numbers? in the Problem Solving forum
“Let''s work with some actual values: The set {2, 4, 6, 8, . . . 54, 56, 58} meets the given conditions. So, the range = 58 - 2 = 56 Answer: A Cheers, Brent”
February 7, 2018
Brent@GMATPrepNow posted a reply to A man covers the first 5 miles of the journey at the rate... in the Problem Solving forum
“Your solution is perfect! Cheers, Brent”
February 7, 2018
Brent@GMATPrepNow posted a reply to Two teams are distributing information booklets. Team A... in the Problem Solving forum
“This REAL WORLD question requires us to find values that are positive INTEGERS. So, for example, we can''t have 1.3 boxes or 12.44 boxes. Team A distributes 60% more boxes of booklets than Team B Since we must have positive integers for these values, the SMALLEST possible numbers are as ...”
February 5, 2018
Brent@GMATPrepNow posted a reply to The probability is 1/2 that a certain coin will turn... 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 1 tails) = 1 - P(NOT getting at least 1 tails) What does it mean to NOT get at least 1 ...”
February 2, 2018
beatthegmat posted a reply to Delete account? in the Suggestions and Feedback forum
“Hey, adam_a, I''ve now deactivated the account. Regards, Sorin”
January 31, 2018
Brent@GMATPrepNow posted a reply to In a mayoral election in the Problem Solving forum
“GIVEN: Candidate Z received 24,000 votes Candidate Y received 1/4 fewer votes than Candidate Z In other words, Candidate Y received 3/4 of the votes that Candidate Z received 3/4 of 24,000 = (3/4)( 24,000) = 18,000 Candidate X received 1/3 more votes than Candidate Y 1/3 of 18,000 = ...”
January 31, 2018
Brent@GMATPrepNow posted a reply to Are x and y both positive in the Data Sufficiency forum
“Target question: Are x and y both positive? Statement 1: 2x - 2y = 1 There are several pairs of numbers that satisfy this condition. Here are two: Case a: x = 1 and y = 0.5, in which case x and y are both positive Case b: x = -0.5 and y = -1, in which case x and y are not both positive ...”
January 31, 2018
Brent@GMATPrepNow posted a reply to If each term in the sum a1+a2+a3+.....+an is either 7 or... in the Problem Solving forum
“APPROACH #2: Another possible approach is to look for a pattern. Since both 7 and 77 have 7 as their units digit, we know that if we take any two terms, their sum will have a units digit of 4 (e.g., 7 + 7 = 14, 7 + 77 = 84, 77 + 77 = 154) Similarly, if we take any three terms, their ...”
January 31, 2018
Brent@GMATPrepNow posted a reply to If each term in the sum a1+a2+a3+.....+an is either 7 or... in the Problem Solving forum
“APPROACH #1: Notice that 77 does not divide into 350 many times. In fact, there can be, at most, four 77''s in the sum So, there are only 5 cases to consider (zero 77''s, one 77, two 77''s, three 77''s and four 77''s) It shouldn''t take long to check the cases. case 1: zero 77''s in ...”
January 31, 2018
Brent@GMATPrepNow posted a reply to A certain clock marks every hour by striking a number... in the Problem Solving forum
“In some regards, this is more of a Reading Comprehension question than a Quantitative question. ... the time required FOR a stroke is exactly equal to the time interval BETWEEN strokes. So, we have moments of silence and moments where the clock is ringing. Each period of silence is the same ...”
January 31, 2018
Brent@GMATPrepNow posted a reply to If 1≥ y ≥0 and z ≤ -2 , then which of the following... in the Problem Solving forum
“My approach would have been the same as David''s. That said, here''s another approach: The question asks "Then which of the following cannot be the value of y-z? " So, if we can find answer choice that CAN BE a value of y-z, we can ELIMINATE it. A. 3. If y = 1 and z = -2, then ...”
January 30, 2018
Brent@GMATPrepNow posted a reply to An integer n that is greater than 1 is said to be... in the Problem Solving forum
“Your question should read as follows: So, n is prime saturated if the largest prime factor of n < √n. If we square both sides of the inequality, we get: n is prime saturated if (the largest prime factor of n)² < n A. 6 = (2)(3) ---> 3² > 6 n is NOT PRIME SATURATED B. ...”
January 30, 2018
Brent@GMATPrepNow posted a reply to A jar contains 12 marbles consisting of an equal... in the Problem Solving forum
“We''re starting with: R, R, R, R, G, G, G, G, B, B, B, B So, P(only 2 colors remaining) = P(all 4 selected marbles are the SAME color) P(all 4 selected marbles are the SAME color) = P(1st marble is ANY color AND 2nd marble matches 1st marble AND 3rd marble matches 1st marble AND 4th marble ...”
January 30, 2018
Brent@GMATPrepNow posted a reply to When integer n is divided by 15, the remainder is 5 in the Problem Solving forum
“Many integer properties questions can be solved by testing values 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, ...”
January 29, 2018
Brent@GMATPrepNow posted a reply to A coach will select the members of a 5-players team from ... in the Problem Solving forum
“P(John and Peter both on the team) = (# of teams that include both John and Peter) / (total # of 5-person teams possible) a) # of teams that include both John and Peter - Put John and Peter on the team. This can be accomplished in 1 way - Select the remaining 3 team-members from the remaining 7 ...”
January 29, 2018
beatthegmat posted a reply to delete account / discontinue email in the Suggestions and Feedback forum
“Hey, zackalack, I''ve now deactivated your account. Regards, Sorin”
January 29, 2018
Brent@GMATPrepNow posted a reply to If an integer n is to be chosen at random from the... in the Problem Solving forum
“First recognize that n, n+1 and n+2 are 3 CONSECUTIVE INTEGERS. Now let''s make some observations: When n = 1, we get: (1)(2)(3), which is NOT divisible by 8 n = 2, we get: (2)(3)(4), which is DIVISIBLE BY 8 n = 3, we get: (3)(4)(5), which is NOT divisible by 8 (4)(5)(6), which is DIVISIBLE ...”
January 29, 2018
Brent@GMATPrepNow posted a reply to If 0 < r < 1 < s < 2, which of the following mus in the Problem Solving forum
“I) r/s r and s are both POSITIVE, and r is less than s. So, it MUST be the case that r/s < 1 II) rs It could be the case that r = 0.9 and s = 1.8, in which case rs = 1.62 So, it NEED NOT be the case that rs < 1 III) s - r It could be the case that r = 0.1 and s = 1.8, in which ...”
January 28, 2018
Brent@GMATPrepNow posted a reply to Car X and Car Y traveled the same 80-mile route... in the Problem Solving forum
“There''s a nice rule we can use here. To set up the rule, recognize that if Y travels 2 times as fast as X, then Y''s travel time will be 1/2 of X''s. Similarly, if Y travels 3 times as fast as X, then Y''s travel time will be 1/3 of X''s. Or if Y travels 1/4 as fast as X, then Y''s travel ...”
January 28, 2018
Brent@GMATPrepNow posted a reply to For what value(s) of k is the following equation satisfied? in the Problem Solving forum
“Your approach is perfect. Since the k''s cancel out, we are left with the nonsensical equation -9 = 6 So, there are NO values of k that will make the left side of the equation equal the right side. Answer: D Cheers, Brent”
January 28, 2018
Brent@GMATPrepNow posted a reply to Remainder question: OG Diagnostic Test in the Problem Solving forum
“Let''s examine a few things about remainders and decimal conversions. 7/4 = 1 3/4 = 1.75. When we divide 7 by 4, the remainder is 3, and .75 = 3/4. 32/5 = 6 2/5 = 6.4. When we divide 32 by 5, the remainder is 2, and .4 = 2/5. 58/20 = 2 18/20 = 2.9. When we divide 58 by 20, the remainder is 18, ...”
January 28, 2018
Brent@GMATPrepNow posted a reply to What is the probability that you get a pair . . . . in the Problem Solving forum
“P(select pair) = P(1st card is ANY card AND 2nd card matches 1st card) = P(1st card is ANY card) x P(2nd card matches 1st card) = 1 x 3/51 = 3/51 = 1/17 = C Aside: P(2nd card matches 1st card) = 3/51, because once 1 card is selected, there are 51 cards remaining in the deck. Among those 51 ...”
January 27, 2018
Brent@GMATPrepNow posted a reply to If the curve represented by y = x^2 – 5x + t intersects .. in the Problem Solving forum
“If the point (-1, 0) is ON the line, then x = -1 and y = 0 is a SOLUTION to the curve''s equation y = x² – 5x + t That is: 0 = (-1)² – 5(-1) + t Evaluate: 0 = 1 + 5 + t Solve: t = -6 So, the original equation is y = x² – 5x + (-6), which is the same as y = x² – 5x - 6 Our goal ...”
January 27, 2018
Brent@GMATPrepNow posted a reply to Eco Wildlife Preserve contains 5x zebras and. . . . . in the Data Sufficiency forum
“ Given: Eco Wildlife Preserve contains 5x zebras and 2x lions, where x is a positive integer. The lions kill z of the zebras Target question: Is the new ratio of zebras to lions less than 2 to 1 ? This is the perfect candidate for rephrasing the target question. ASIDE: If we take the ...”
January 27, 2018
Brent@GMATPrepNow posted a reply to Bob bikes to school in the Problem Solving forum
“Here''s an algebraic solution: Let d = the TOTAL distance to school. Bob had a flat tire exactly halfway to school So, d/2 = distance spent biking and d/2 = distance spent walking We can write: (time spent biking) + (time spent walking) = t time = distance/speed We get: (d/2)/x + ...”
January 27, 2018
Brent@GMATPrepNow posted a reply to If 4 is one solution of the equation x^2 + 3x + k = 10, wher 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 ...”
January 27, 2018
Brent@GMATPrepNow posted a reply to If x, y, and z are positive integers, is x+y divisible by 2? in the Data Sufficiency forum
“Target question: Is x+y divisible by 2? Statement 1: x+z is divisible by 2 No information about y. Statement 1 is NOT SUFFICIENT Statement 2: y+z is divisible by 2 No information about x. Statement 2 is NOT SUFFICIENT Statements 1 and 2 combined Statement 1: If x+z is divisible ...”
January 26, 2018
Brent@GMATPrepNow posted a reply to Given that 1+2+.......+n=n(n+1)/2 and in the Problem Solving forum
“Answer = (Sum of all integers from 1 to 100 inclusive) - (Sum of integers from 1 to 100 that are SQUARES of integers) Note: 100 is the greatest SQUARE among the numbers from 1 to 100. 100 = 10² So, answer = (100)(100 + 1)/2 - (10)(10 + 1)(2)(10 + 1)/6 = (100)(101)/2 - (10)(11)(21)/6 = ...”
January 26, 2018
Brent@GMATPrepNow posted a reply to If x and y are integers, which of the following CANNOT be th in the Problem Solving forum
“Let''s do this systematically: 0² = 0 1² = 1 2² = 4 3² = 9 4² = 16 5² = 25 6² = 36 7² = 49 8² = 64 9² = 81 10² = 100 11² = 121 A. 121 = 0² + 11² ELIMINATE A B. 122 = 1² + 11² ELIMINATE B C. 123 = can''t eliminate D. 125 = 10² + 5² ...”
January 25, 2018
Brent@GMATPrepNow posted a reply to If x and y are integers, which of the following CANNOT be th in the Problem Solving forum
“'' Be careful; if x = 0 and y = 11, then we get: 0² + 11² = 121 Eliminate A Cheers, Brent”
January 25, 2018
Brent@GMATPrepNow posted a reply to Beat the GMAT 60 Day- Time commitment & Diagnostic frequ in the The 60-Day GMAT Study Guide forum
“1. The time it takes to complete each day''s activities will vary from person to person. It also varies depending on which resource you use (GMAT Prep Now videos or MGMAT books). Also, some days take longer to complete. If you have difficulties keeping up, don''t worry. You can take longer than a ...”
January 25, 2018
beatthegmat posted a reply to delete account / discontinue email in the Suggestions and Feedback forum
“Hey, pwulfers, I''ve now deactivated your account. Regards, Sorin”
January 25, 2018
Brent@GMATPrepNow posted a reply to Is quadrilateral ABCD is a parallelogram? in the Data Sufficiency forum
“Hi ardz24, I just posted that question on BTG 2 hours ago (http://www.beatthegmat.com/is-quadrilateral-abcd-is-a-parallelogram-t300219.html) Cheers, Brent”
January 25, 2018
Brent@GMATPrepNow posted a reply to Master List of Quant/GMAT Math Resources in the GMAT Math forum
“If it''s okay with you, I''d like to add: Strategies for solving Geometry Data Sufficiency Questions https://www.gmatprepnow.com/module/gmat-data-sufficiency/video/1103 Must-know Triangle Properties https://www.gmatprepnow.com/module/gmat-geometry/video/860 Cheers, Brent”
January 25, 2018
Brent@GMATPrepNow posted a reply to The ratio of dogs to cats to mice at Paws and Claws in the Problem Solving forum
“One more approach: Given: ratio of dogs to cats to mice = 3 : 5 : 4 So, some possible scenarios are: 3 dogs, 5 cats, and 4 mice 6 dogs, 10 cats, and 8 mice 9 dogs, 15 cats, and 12 mice 12 dogs, 20 cats, and 16 mice . . . IMPORTANT: Notice that the number of mice is always divisible ...”
January 25, 2018
Brent@GMATPrepNow posted a new topic called Is quadrilateral ABCD is a parallelogram? in the Data Sufficiency forum
“Is quadrilateral ABCD is a parallelogram? 1) All four angles in quadrilateral ABCD are right angles 2) All four sides of quadrilateral ABCD are equal length Answer: D Source: www.gmatprepnow.com Difficulty level: 500-550”
January 24, 2018
Brent@GMATPrepNow posted a reply to A spaceship that is traveling 3,600 kilometers per hour... in the Problem Solving forum
“No, BTG doesn''t have that functionality (yet). I''d say the question falls in the 500-600 range Cheers, Brent”
January 23, 2018
Brent@GMATPrepNow posted a reply to GMAT Prep Now Account Giveaway/Contest #41 in the GMAT Strategy forum
“The deadline for the latest contest has passed, and the winner is u/Perseveer (Reddit user) The winning entry was 6 Here are all of the entries: 1, 1, 1, 3, 3, 3, 4, 4, 6, 8, 13 Cheers, Brent”
January 23, 2018
Brent@GMATPrepNow posted a reply to If -1 < h < 0, which of the following has the greatest in the Problem Solving forum
“Your suggested strategy is perfect. Since there can be only 1 correct answer, then we can pick any value of h that meets the condition that -1 < h < 0 If h = -1/2, then the 5 answer choices evaluate as follows: A) 1 - (-1/2) = 1.5 B) 1 + (-1/2) = 0.5 C) 1+ (-1/2)² = 1 + 0.25 = ...”
January 23, 2018
Brent@GMATPrepNow posted a reply to What is the value of (k – w ) + (k – x ) + (k – y )? in the Data Sufficiency forum
“Target question: What is the value of (k – w ) + (k – x ) + (k – y )? This is a good candidate for rephrasing the target question. Take: (k – w ) + (k – x ) + (k – y ) Simplify to get: 3k – w – x – y Rewrite as: 3k – (w + x + y) REPHRASED target question: What is ...”
January 23, 2018
Brent@GMATPrepNow posted a reply to A gardener is going to plant 2 red rosebushes and 2... in the Problem Solving forum
“We can also apply probability rules: P(2 middle bushes are red) = P(1st bush is white AND 2nd bush is red AND 3rd bush is red AND 4th bush is white) = P(1st bush is white) x P(2nd bush is red) x P(3rd bush is red) x P(4th bush is white) = 2/4 x 2/3 x 1/2 x 1/1 = 1/6 = B Cheers, Brent”
January 23, 2018
Brent@GMATPrepNow posted a reply to A gardener is going to plant 2 red rosebushes and 2... in the Problem Solving forum
“As with many probability questions, we can also solve this using counting techniques. P(2 middle are red) = (# of outcomes with 2 red in middle)/(total number of outcomes) Label the 4 bushes as W1, W2, R1, R2 total number of outcomes We have 4 plants, so we can arrange them in 4! ways = ...”
January 23, 2018
Brent@GMATPrepNow posted a reply to The inside dimensions of a rectangular wooden are... in the Problem Solving forum
“Volume of cylinder = π(radius²)(height) There are 3 different ways to position the cylinder (with the base on a different side each time). You can place the base on the 6x8 side, on the 6x10 side, or on the 8x10 side If you place the base on the 6x8 side, then the cylinder will have height ...”
January 23, 2018
Brent@GMATPrepNow posted a reply to Probability 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 2500 people, and the two characteristics are: - invests in municipal bonds or does ...”
January 21, 2018
Brent@GMATPrepNow posted a reply to Sentence Correction in the Problem Solving forum
“We can also solve the question using one variable We can see that Kate charged the fewest hours, so... Let x =the number of hours Kate charged Pat charged twice as much time to the project as Kate So, 2x = the number of hours Pat charged Pat charged 1/3 as much times as Mark In other ...”
January 20, 2018
Brent@GMATPrepNow posted a reply to Should I buy Manhattan Prep 5th or 6th edition? in the The 60-Day GMAT Study Guide forum
“Both editions are good. HOWEVER, the 60-day guide is aligned with the 5th edition (not the 6th edition) Cheers, Brent”
January 19, 2018
Brent@GMATPrepNow posted a reply to What is the standard deviation of the values in the Data Sufficiency forum
“Target question: What is the standard deviation of the values of the 20 coins in a certain jar ? Statement 1: The average (arithmetic mean ) value of the coins in the jar is 25 cents . There are several cases that satisfy statement 1. Here are two: Case a: All 20 coins are quarters (each is ...”
January 19, 2018
Brent@GMATPrepNow posted a reply to On a weekend, 6 college friends went skiing and... in the Problem Solving forum
“If the total cost is divisible by 6, then each of the 6 friends will pay an integer amount. Take answer choice A ($126) for example. 126 is divisible by 6$126/6 = $31 So, each person pays an integer amount ($31 each) ELIMINATE A The question is basically asking us to find the answer ...”
January 19, 2018
Brent@GMATPrepNow posted a reply to The male alpine rabbits of the Tzatsek nature reserve... in the Problem Solving forum
“Here''s an algebraic solution that uses 2 variables: Let M = the # of male rabbits BEFORE the disease struck. Let F = the # of female rabbits BEFORE the disease struck. We''re told that the male/female ratio was 3:2 BEFORE the disease. So, we can write: M/F = 3/2 Cross multiply to get: ...”
January 19, 2018
Brent@GMATPrepNow posted a reply to What is the area of an equilateral triangle... in the Problem Solving forum
“Area of an equilateral triangle = (s²/4)(√3) (where s = length of one side) So... Area = (60²/4)(√3) = (3600/4)(√3) = 900√3 = E Cheers, Brent”
January 18, 2018
Brent@GMATPrepNow posted a reply to When running a mile during a recent track meet... in the Problem Solving forum
“The long approach is to convert 11/25 of a minute to seconds and then ADD that unaccounted time to Nuria''s time (of 5 minutes, 44 seconds) However, when we check the answer choices before performing any calculations (ALWAYS check the answer choices before performing any calculations), we see that ...”
January 18, 2018
Brent@GMATPrepNow posted a reply to What is the value of . . . . . . . in the Data Sufficiency forum
“Target question: What is the value of r² − 2rs + s²? This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: Notice that r² − 2rs + s² is a "special product" It can be factored as follows: r² − ...”
January 18, 2018
Brent@GMATPrepNow posted a reply to A certain rectangular window is three times as long... in the Problem Solving forum
“Let''s continue where you left off. You have: 2L + 2W = 28 L = 3W Take the top equation and replace L with 3W (from 2nd equation) to get: 2(3W) + 2W = 28 Expand: 6W + 2W = 28 Simplify: 8W = 28 So, W = 28/8 = 3.5 Check the answer choices.....only one answer choice has 3.5 as one of ...”
January 18, 2018
Brent@GMATPrepNow posted a reply to Is 5 the median of Set X? (1) Set X has . . . . . in the Data Sufficiency forum
“Target question: Is 5 the median of Set X? Statement 1: Set X has 6 elements, which are odd positive integers. There are several sets that satisfy statement 1. Here are two: Case a: Set X = {1, 5, 5, 5, 5, 9} . In this case, 5 IS the median of set X Case b: Set X = {1, 7, 7, 7, 7, 9} . In ...”
January 18, 2018
Brent@GMATPrepNow posted a reply to The number of rooms at Hotel G is 10 less than twice the num in the Problem Solving forum
“We can also solve the question using 1 variable Let x = number of rooms at Hotel H The number of rooms at Hotel G is 10 less than twice the number of rooms at Hotel H So, 2x - 10 = number of rooms at Hotel G The total number of rooms at Hotel G and Hotel H is 425 We can write: x + (2x - ...”
January 17, 2018
Brent@GMATPrepNow posted a reply to The sum of the mean, the median, and the range of . . . . in the Problem Solving forum
“Given: {1, 2, 6} Mean = (1 + 2 + 6)/3 = 9/3 = 3 Median = 2 Range = 6 - 1 = 5 SUM = 3 + 2 + 5 = 10 Answer: E Cheers, Brent”
January 16, 2018
Brent@GMATPrepNow posted a reply to Is the nth root of n greater than the cube root of 3? in the Data Sufficiency forum
“IMPORTANT: This question illustrates a situation in which we need not perform any calculations. Instead, we need only recognize that we COULD perform calculations, which would allow us to determine whether or not a statement is sufficient. Target question: Is (nth root of n) greater than (cube ...”
January 16, 2018
Brent@GMATPrepNow posted a new topic called GMAT Prep Now Account Giveaway/Contest #41 in the GMAT Strategy forum
“Enter to win a 6-month GMAT video course from GMATPrepNow.com. The rules are very simple: Submit any positive integer (1, 2, 3, etc.) as your entry, and the contestant who submits the smallest unique number wins a 6-month account at www.GMATPrepNow.com The key word here is UNIQUE. For ...”
January 16, 2018
Brent@GMATPrepNow posted a reply to GMAT Prep Now Account Giveaway/Contest #40 in the GMAT Strategy forum
“The deadline for the latest contest has passed, and the winner is u/Benoitale (Reddit user) The winning entry was 4 Here are all of the entries: 1, 1, 2, 2, 3, 3, 3, 3, 3, 4, 5, 6, 8, 8 Cheers, Brent”
January 16, 2018
Brent@GMATPrepNow posted a reply to What is the product of all roots of the equation in the Problem Solving forum
“Another approach: 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 + 1)² = | x + 1| Apply ...”
January 16, 2018
Brent@GMATPrepNow posted a reply to DS Ratios in the Data Sufficiency forum
“We can rephrase this as . . . REPHRASED target question: Does m/r = x/y? We may find it useful to take the equation m/r = x/y and cross-multiply to get my = rx. This allows us to rephrase the target question in one more way . . . RE-REPHRASED target question: Does my = rx? Aside: We ...”
January 15, 2018
Brent@GMATPrepNow posted a reply to DS number line in the Data Sufficiency forum
“Another approach is the sketch the cases on a number line. Target question: Is x positive? Statement 1: On the number line, 0 is closer to x – 1 than to x. First, recognize that x-1 will always be to the left of x. Second, recognize that there are 3 possible ways to place x-1 and x ...”
January 15, 2018
Brent@GMATPrepNow posted a reply to 1.4ab5 in the Data Sufficiency forum
“Target question: What is the value of 10 - x? Given: X = 1.4ab5 Statement 1: If x is rounded to the nearest hundredth, then 10 – x = 8.56 10 - 1.44 = 8.56 So, x rounded to the nearest HUNDREDTH = 1.44 So, x COULD equal 1.4355, 1.4365, 1.4375, 1.4385, 1.4395, 1.4405, 1.4415, 1.4425, ...”
January 15, 2018
Brent@GMATPrepNow posted a reply to percents in the Data Sufficiency forum
“The great thing about DS questions is that we aren''t required to perform calculations if we know that we COULD perform those calculations. Here''s what I mean: Target question: What amount must be invested at k percent simple annual interest for one year to yield the same amount of dollars ? ...”
January 15, 2018
Brent@GMATPrepNow posted a reply to Why not the answer is D? in the Data Sufficiency forum
“Target question: What was the original price? Given: The price of a television set was reduced by 25 percent. Statement 1: The reduced price was $187.50. Let x = original price It is given that the price of a television set was reduced by 25 percent. So, the reduced price = 0.75x ...” January 15, 2018 Brent@GMATPrepNow posted a reply to Integers Properties in the Problem Solving forum “I think the formatting is a little off here :-) Cheers, Brent” January 14, 2018 Brent@GMATPrepNow posted a reply to In what proportion must flour at$0.8 per pound... in the Problem Solving forum
“We can solve this using 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) + ... Let C = pounds of Cheap flour ($0.8 per pound) needed Let E = pounds of Expensive flour ...” January 14, 2018 Brent@GMATPrepNow posted a reply to A certain car dealership offer its newest... in the Problem Solving forum “Here''s one approach: Take the task of choosing colors break it into stages. Stage 1: Choose the exterior color Since there are 10 color choices, we can complete this stage in 10 ways Stage 2: Choose the interior color At this point, we can''t choose the color that was used for the ...” January 13, 2018 Brent@GMATPrepNow posted a reply to Q is a set of four distinct prime numbers. If the sum . . . in the Problem Solving forum “We need to minimize the four distinct prime numbers. We''re told that the SUM of the four numbers is EVEN. This means ALL FOUR prime numbers must be odd ASIDE: We know this because there is only one even prime number (2). Since the four numbers are distinct, there can be, AT MOST, one 2. ...” January 13, 2018 Brent@GMATPrepNow posted a reply to If x and y are integers greater than 1 and x>y . . . . in the Data Sufficiency forum “Target question: What is the value of x? Given: x and y are integers greater than 1 and x > y Statement 1: x+y=10 There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 9 and y = 1. In this case, the answer to the target question is x = 9 Case b: x ...” January 13, 2018 Brent@GMATPrepNow posted a reply to John deposited$10,000 to open a new savings account . . . in the Problem Solving forum
“When the number of "compounding" periods is only 2 or 3, we can just calculate the interest for each period. 4% annual interest, compounded quarterly, means that for each quarter year (3 months), we are adding an interest of 1% to the amount in the bank. We can practically do this in our ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to Is 5^k less than 1,000? in the Data Sufficiency forum
“Target question: Is 5^k less than 1000? Statement 1: 5^(k+1) > 3000 First notice that 5^(k+1) = (5^k)(5^1) So, we can take 5^(k+1) > 3000 and divide both sides by 5 to get: 5^k > 600 There are several possible cases to consider. Here are two: case a: 5^k = 601, in which case 5^k is ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to Cans of OJ concentrate in the Problem Solving forum
“Here''s another approach: The first part tells that, for every 1 can of concentrate, we can make 4 cans of juice. Let''s be even more generic, for 1 volume of concentrate, we can make 4 volumes of juice. Okay, now notice that we have a problem with the volume mismatch in the question. It ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to An investment compounds annually at an interest rate of 34.1 in the Problem Solving forum
“We can use fractions to solve this question. Each year, the investment increases 34.1% This is very close to an increase of 1/3 (33.33%) So, if the investment increases by 1/3 each year, then each year, we can find the value of the investment by multiplying last year''s value by 4/3 (this ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to AMixture/ratio problem 3 in the Problem Solving forum
“The bottle is filled 80% to capacity, and then 70ml of rum makes the bottle 100% filled to capacity. So, 70ml represents 20% of the capacity. So, BEFORE the rum was added, there were 280ml of liquid in the bottle (i.e., if 70ml represents 20% of capacity, then 280ml represents 80% of capacity) ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to % increase in the Problem Solving forum
“Let''s plug in some NICE NUMBERS. Let''s say the original output is 100 widgets. - After a 10% increase the new output = 100 + 10 = 110 widgets - After a 20% increase the output = 110 + 22 = 132 widgets We want to get back to the original output. In other words, we want to decrease from ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to To find the fraction in the Problem Solving forum
“You were almost there. It may be easier if we rephrase the question. Notice that these two questions are EQUIVALENT. "What fraction of X is Y?" "Y is what fraction of X?" So, "What fraction of 3/4 + 1/2 is 3/4 - 1/2?" is the same as "3/4 - 1/2 is what ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to 7 teams in the Problem Solving forum
“The first thing we should recognize is that, if each of the 7 teams get their maximum of 3 wins each, then the total number of wins is 21. So, the ONLY WAY to distribute 20 wins among 7 teams is for six teams to get 3 wins and one team to get 2 wins. For example: Team 1: 3 wins Team 2: 3 ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to Compound interest in the Problem Solving forum
“You can use this formula to calculate compound interest: Final balance = P( 1 + r/c)^nc where: P = the principal (the initial investment) r = the annual interest rate expressed as a decimal c = the number of times the interest is compounded each year n = the number of years the investment ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to stack 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 ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to ratio problem 3 in the Problem Solving forum
“A fast approach is to ASSIGN values that match the given information. The ratio of purple tulips to red tulips is 3:5 So, let there be 3 purple tulips and 5 red tulips. ...the number of white roses in Erica''s garden is twice the number of purple tulips Above, we said there are 3 purple ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to Ratios problem in the Problem Solving forum
“The ratio of two positive numbers is 3 to 4. Let 3x = the smaller number Let 4x = the larger number Aside: Notice that this ensures that their ratio will equal 3/4, since 3x/4x = 3/4 If k is added to each number the new ratio will be 4 to 5 . . . When k is added to each value, the NEW ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to simple interest rate in the GMAT Math forum
“With simple interest, one''s investment increases the SAME AMOUNT each year, based on the INITIAL investment. $18,400 -$16,000 = $2400 So, the investment increased$2400 over 2 YEARS $2400 ÷ 2 =$1200 So, the ANNUAL increase is $1200 The INITIAL INVESTMENT was$16,000 $1200/$16,000 ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to The price of a certain computer is discounted by 20% every in the Problem Solving forum
“If the computer price decreases 20%, then it retains 80% of its value. So, for example, if the original price is $50, then after 1 year, the reduced price = 80% of$50 (i.e., $40) NOTE: 80% = 4/5 Year 0: let the price = x After 1 year: the price = x(4/5) After 2 years: the price = ...” January 13, 2018 Brent@GMATPrepNow posted a reply to Last year in the Problem Solving forum “Let''s use the INPUT-OUTPUT approach. Another 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 ...”
January 13, 2018
Brent@GMATPrepNow posted a reply to O is the center of the semicircle. if angle BCO = 6√3... in the Problem Solving forum
“I don''t think you correctly transcribed the question. If we''re not given any lengths at all, it''s impossible to find the area of triangle ABO Cheers, Brent”
January 13, 2018
Brent@GMATPrepNow posted a reply to If x and y are integers greater than 1 and x>y, what is t in the Data Sufficiency forum
“Target question: What is the value of x? Given: x and y are integers greater than 1 and x > y Statement 1: x+y=10 There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 9 and y = 1. In this case, the answer to the target question is x = 9 Case b: x ...”
January 12, 2018
Brent@GMATPrepNow posted a reply to Max purchased a guitar for a total of $624, in the Data Sufficiency forum “Target question: Was the sales tax rate greater than 3 percent? Given: Max purchased a guitar for a total of$624, which consisted of the price of the guitar and the sales tax. Statement 1: The price of the guitar that Max purchased was less than $602. Let''s see what would happen if the ...” January 12, 2018 Brent@GMATPrepNow posted a reply to Percentage in the Problem Solving forum “Start:$10,000 First year +10% 10% of $10,000 =$1000 So, we get $10,000 +$1000 = $11,000 Second year +5% 5% of$11,000 = $550 So, we get$11,000 + $550 =$11,550 Third year -10% 10% of $11,550 =$1,155 So, we get $11,550 -$1155 = \$10,395 Answer: B Aside: We have a ...”
January 12, 2018