GMATGuruNY posted a reply to Is x > y ? in the Data Sufficiency forum
“If A, then B does not imply If B, then A. True statement: If John is in Times Square, then John is in New York. The following statement is NOT necessarily true. If John is in New York, then John is in Times Square. Is x > y? Statement 1: 5x > 3y Statement 2: 4x > 7y Each ...”
Yesterday
GMATGuruNY posted a reply to Is x > y ? in the Data Sufficiency forum
“I received a PM requesting that I post a response. The issue at hand is how to combine the two inequalities. Visually-oriented test-takers might find it helpful to plot the values on a number line. Statement 1: (2/5)x > (3/8)y x > (5/2)(3/8)y x > (15/16)y Statement 2: (3/7)x ...”
Yesterday
GMATGuruNY posted a reply to Tom travels the same distance in 4 steps as Alice travels in in the Problem Solving forum
“Since each of Alice''s steps = 36 cm, the distance traveled by Alice in 5 steps = 5*36 = 180 cm. Since Tom requires only 4 steps to travel this 180-cm distance, each of Tom''s steps = 180/4 = 45 cm. Thus, the distance traveled by Tom in 18 steps = 18*45 = 810 cm. The correct answer is E.”
July 17, 2019
GMATGuruNY posted a reply to Oil, vinegar, and water are mixed in a 3 to 2 to 1 ratio to in the Problem Solving forum
“Since oil:vinegar:water = 3:2:1, we get: part attributed to oil = 3 cups part attributed to vinegar = 2 cups part attributed to water = 1 cup sum of the parts = 3+2+1 = 6 cups Since Larry has 8 cups of oil, we get: (available oil)/(part attributed to oil) = 8/3. The fraction in blue implies ...”
July 17, 2019
GMATGuruNY posted a reply to Working together at their respective constant rates, Machine in the Problem Solving forum
“The prompt should read as follows: Since A+B take 8 hours to produce 1200 units, the combined rate for A+B = w/t = 1200/8 = 150 units per hour. Since B take 50% more time than the 8 hours required when A+B work together, B''s time = 8 + (50% of 8) = 8 + 4 = 12 hours. Since B takes 12 ...”
July 16, 2019
GMATGuruNY posted a reply to Tom painted 1/3 of a wall red, 1/5 of the wall blue and the in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total area. When the correct answer is plugged in, the area painted black = 238. Since 1/3 of the wall is painted red, it is almost certain that correct answer is a multiple of 3. For an integer to be a multiple of 3, its digit sum must be a ...”
July 15, 2019
GMATGuruNY posted a reply to There are three varieties of sugar in a store. Sugar S1 in the Data Sufficiency forum
“Statement 1: Case 1: A=10 kg and B=10 kg, for a total of 20 kg In this case, A=B, so the answer to the question stem is NO. Case 2: A=11 kg and B=9 kg, for a total of 20 kg In this case, A>B, so the answer to the question stem is YES. Since the answer is NO in Case 1 but YES in Case 2, ...”
July 14, 2019
GMATGuruNY posted a reply to In the figure shown, what is the value of x? in the Data Sufficiency forum
“Neither statement alone is sufficient to determine the value of x. When we combine the two statements, here''s an efficient way to determine whether we have sufficient information. 1. Plug in values for all of the angle measurements, satisfying the constraints in the problem and the rules of ...”
July 14, 2019
GMATGuruNY posted a reply to Between the first day of May and last day in June, the price in the Problem Solving forum
“We can PLUG IN THE ANSWERS. When the correct answer is plugged in, Blue''s resulting price and Melange''s resulting price will be EQUAL. D: 100 Here, Blue''s initial price is 100% of Melange''s initial price, implying that the two initial prices are equal. Let Blue = May = $100. From May to ...”
July 12, 2019
GMATGuruNY posted a reply to What is the remainder when a is divided by 4? in the Data Sufficiency forum
“Statement 1: An odd integer can be written as follows: 2x+1, where x is an integer. Since a is the square of an odd integer, we get: a = (2x+1)² = (2x)² + 2(2x)(1) + 1² = 4x² + 4x + 1 = 4(x²+x) + 1 = (multiple of 4) + 1 Since a is equal to 1 more than a multiple of 4, dividing a by 4 will ...”
July 11, 2019
GMATGuruNY posted a reply to If m and n are positive integers and r is the remained when in the Data Sufficiency forum
“5(10^n) = 5 followed by n zeros. If n=1, then 5(10^n) = 5*10¹ = 5 followed by 1 zero = 50 If n=2, then 5(10^n) = 5*10² = 5 followed by 2 zeros = 500 If n=3, then 5(10^n) = 5*10³ = 5 followed by 3 zeros = 5000 Rule: An integer whose digits sum to a multiple of 3 is itself a multiple of 3. ...”
July 9, 2019
GMATGuruNY posted a reply to What is 1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56? in the Problem Solving forum
“1/2 + 1/6 + 1/12 + 1/20 + 1/30 + 1/42 + 1/56 = 1/2 + (1/2 - 1/3) + (1/3 - 1/4) + (1/4 - 1/5) + (1/5 - 1/6) + (1/6 - 1/7) + (1/7 - 1/8) = 1/2 + 1/2 - 1/8 = 1 - 1/8 = 7/8 The correct answer is C.”
July 9, 2019
GMATGuruNY posted a reply to Inequalities :If x is an integer, what is the value of x? in the Data Sufficiency forum
“In statement 1, |x²| is redundant: since x² cannot be negative, |x²| = x². Statement 1: |x-x²|=2 x - x² = ±2 x(1-x) = ±2. The resulting equation implies that x is a factor of ±2, yielding the following options: x=±1 or x=±2. Check which of these values are valid solutions for ...”
July 7, 2019
GMATGuruNY posted a reply to What is the value of n in the equation: - 25 + 19 + n = s ? in the Data Sufficiency forum
“What do we want? The value of n. Before we look at the statements, what do we have? A linear equation with two variables (n and s). To answer the question stem, what do we need? Another linear equation with one or both of the variables. Each statement gives us what we need and thus is ...”
July 6, 2019
GMATGuruNY posted a reply to If a coin has an equal probability of landing heads up or in the Problem Solving forum
“P(HHT) = 1/2 * 1/2 * 1/2 = 1/8. Since T can occur on the 1st, 2nd or 3rd flip, we multiply by 3: 3(1/8) = 3/8 = 0.375 The correct answer is C.”
July 6, 2019
GMATGuruNY posted a reply to The British Admiralty and the War Office in the Sentence Correction forum
“Neuroscientists are now drawing solid conclusions about the disease. Here, the disease serves as the object of the preposition about. A clause includes both a subject and a verb. A clause may function as a noun. SC720 in the OG18: Neuroscientists are now drawing solid conclusions about how ...”
July 4, 2019
GMATGuruNY posted a reply to What is the number of solutions of x = |x-|30-2x||? in the Problem Solving forum
“|x-|30-2x|| = x if the blue portion is equal to x or -x. Case 1: x-|30-2x| = x 0 = |30-2x| The equation above is valid if 30-2x=0: 30-2x = 0 30 = 2x 15 = x Case 2: x-|30-2x| = -x 2x = |30-2x| Case 2a: 2x = 30-2x 4x = 30 x = 30/4 = 7.5 Case 2b: -2x = 30-2x 0 = 30 Not valid. ...”
July 4, 2019
GMATGuruNY posted a reply to The LCM of three numbers is four times their GCF. Which of in the Problem Solving forum
“Try to prove that I, II and III DON''T have to be true. To disprove I -- which states that at least one number must be odd -- let the GCF = 2. Since the LCM = 4(GCF), the LCM = 8. In this case: The greatest factor common of all three numbers must be 2. The least value divisible by all 3 ...”
July 3, 2019
GMATGuruNY posted a reply to In addition to her work on the miocene homicide fossil in the Sentence Correction forum
“A possessive such her may serve to refer to a preceding possessive. More importantly, her is a personal pronoun. Only a PERSON or PEOPLE may serve as referent for a personal pronoun (he, she, him, his, her). Since only a person or people may serve as referent for a personal pronoun -- and a ...”
July 1, 2019
GMATGuruNY posted a reply to A palindrome, such as 12321, is a number that remains the sa in the Problem Solving forum
“The difference between the two palindromes = 32. Since subtracting 32 from the 4-digit palindrome must yield a 3-digit palindrome. the 4-digit palindrome must be just a bit more than 1000. Test 1001: 1001 - 32 = 969 Success! Subtracting 32 from 1001 (a 4-digit palindrome) yields 969 (a 3-digit ...”
July 1, 2019
GMATGuruNY posted a reply to Ellipsis in comparison in the Sentence Correction forum
“Since the red portion refers to the FUTURE -- the expected level in 2010 -- the verb should be in the future tense: a level that WILL BE more than one-third higher than was the level in 1990 From context, we know that a level refers to the expected level of carbon emissions in 2010. Since ...”
June 30, 2019
GMATGuruNY posted a reply to The ratio of flour to water to sugar in a recipe is 7:4:1. T in the Problem Solving forum
“Original ratio: F:W:S = 7:4:1 A new recipe calls for a doubling of the ratio of flour to water. Doubling F/W = 7/4, we get: 2 * 7/4 = 7/2 Resulting ratio: F:W:S = 7:2:1 A halving of the ratio of flour to sugar. Halving F/S = 7/1, we get: (1/2)(7/1) = 7/2 Resulting ratio: F:W:S = ...”
June 30, 2019
GMATGuruNY posted a reply to Amy's grade was 90th percentile of the 80 grades for her in the Problem Solving forum
“Alternate approach: In Amy''s 80-student class, her percentile = 90. In the 100-student class, 19 scores are higher than Amy''s, implying that 81 scores are lower. Thus: Amy''s percentile in the 100-student class = 81. Amy''s AVERAGE percentile for all 180 students = (80*90 + 100*81)/180 = ...”
June 30, 2019
GMATGuruNY posted a reply to -2 ≤ x ≤ -1 and 1 ≤ y ≤ 2. What is the greatest poss in the Problem Solving forum
“(x+y)/x = 1 only if y=0. Since the range for y does not include 0, eliminate E. If x=-2 and y=1, then (x+y)/y = (-2+1)/-2 = 1/2. Since 1/2 is the greatest of the remaining answer choices, the correct answer is D.”
June 26, 2019
GMATGuruNY posted a reply to A certain basketball team that has played 2/3 of its games in the Problem Solving forum
“Games played thus far = 17 wins + 3 losses = 20. Since these 20 games constitute 2/3 of the total number of games, we get: 20 = (2/3)T 60 = 2T 30 = T Since the team must win at least 3/4 of these 30 games, it may lose at most 1/4 of these 30 games: (1/4)30 = 7.5 Implication: The total ...”
June 25, 2019
GMATGuruNY posted a reply to What is the average (arithmetic mean) of all 5-digit numbers in the Problem Solving forum
“For any set that is SYMMETRICAL ABOUT THE MEDIAN: average = median Number of integers that can be composed from the 5 given digits = 5! = 120. Since the number of integers is EVEN, the median will be equal to the average of the two middle values: ...53791, 53917, 53971, 57139, 57193, ...”
June 25, 2019
GMATGuruNY posted a reply to Ashok and Brian are both walking east along the same path; in the Data Sufficiency forum
“Let A = A''s rate and B = Brian''s rate. Ashok has to CATCH-UP by 30 miles. The CATCH-UP rate is equal to the DIFFERENCE between the two rates. If A = 3mph, while B = 2mph, then every hour A walks 1 more mile than B, with the result that every hour A catches up by 1 mile -- the DIFFERENCE ...”
June 23, 2019
GMATGuruNY posted a reply to GMAT Official Guide 2019 The city of Workney in the Critical Reasoning forum
“When the correct answer is negated, the conclusion will be invalidated. Conclusion: Selling 9 tokens for $10 will alleviate the burden on POOR PEOPLE. E, negated: More riders would regularly purchase 18 tokens at once than would purchase only 9 tokens at once. Since this negation tells us ...”
June 23, 2019
GMATGuruNY posted a reply to What is the value of 1 / (√2+√1) + 1 / (√3+√2) + 1/( in the Problem Solving forum
“1/(√2+√1) = √2-√1) + (√3-√2) + (√4-√3) +...+ (√24-√23) + (√25-√24) The red values all cancel out, yielding the following: -√1 + √25 = -1 + 5 = 4 The correct answer is D.”
June 20, 2019
GMATGuruNY posted a reply to OG 2018 CR Q Political theorist: Even with in the Critical Reasoning forum
“Since the correct answer must SUPPORT the conclusion that a national leader with such , the argument above seems best classified as a STRENGTHEN CR.”
June 19, 2019
GMATGuruNY posted a reply to If is n is multiple of 5, and n=p^2*q where p and q are prim in the Problem Solving forum
“Try to prove that four of the answer choices DO NOT have to be a multiple of 25. The correct answer will be the remaining answer choice. In order for n to be a multiple of 5, either p and/or q must be a multiple of 5. Since the goal is to prove that four of the answer choices do NOT have to ...”
June 19, 2019
GMATGuruNY posted a reply to What is the value of the following sum? 1/(1*2) + 1/(2*3) + in the Problem Solving forum
“x = 1/(1*2) + 1/(2*3) + 1/(3*4) + 1/(4*5) + 1/(5*6) 60x = 60D.”
June 19, 2019
GMATGuruNY posted a reply to If x, y and z are three different non-negative integers, whi in the Problem Solving forum
“i: |x−y| = |x+y| = |y−z| This statement is true if x=0, y=1 and z=2: |0-1| = |0+1| = |1-2| 1 = 1 = 1 Since the correct answer must include i, eliminate B and C. ii) x^y = y^z This statement is true if x=1, y=2 and z=0: 1^2 = 2^0 1 = 1 Since the correct answer must include ii, ...”
June 18, 2019
GMATGuruNY posted a reply to Over the first x games of his basketball season, Martin in the Problem Solving forum
“Since the seasonal average = 30 points per game, the total number of points must be a MULTIPLE OF 30. Over the first x games of his basketball season, Martin averaged 32 points per game. In his last game, he scored 14 points. Implication: 32x + 14 = MULTIPLE OF 30 32x = (MULTIPLE OF 30) - 14 ...”
June 18, 2019
GMATGuruNY posted a reply to If |2x|>|3y|, is x >y? 1) x>0 2) y>0 in the Data Sufficiency forum
“Statement 1: Test x=3. Plugging x=3 into |2x|>|3y|, we get: |2*3|>|3y| 6 > 3|y| |y| < 2 -2 < y < 2 Since x=3 and -2 < y < 2, we get: x > y. Test x=1/2. Plugging x=1/2 into |2x|>|3y|, we get: |2 * 1/2|>|3y| 1 > 3|y| |y| < 1/3 -1/3 < y < ...”
June 18, 2019
GMATGuruNY posted a reply to How many arrangements of the letters A, C, C, E, N, T includ in the Problem Solving forum
“Good arrangements = total arrangements - bad arrangements. Total arrangements: Number of ways to arrange 6 elements = 6!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of identical elements can be ARRANGED. The reason: When the identical ...”
June 18, 2019
GMATGuruNY posted a reply to If \(\frac{(ab)^2+3ab-18}{(a-1)(a-2)}=0\) where \(a\) and in the Problem Solving forum
“The equation is valid only if (ab)²+3ab-18 = 0. I: b=1 Plugging b=1 into (ab)²+3ab-18 = 0, we get: a²+3a-18 = 0 (a+6)(a-3) = 0 a=-6 or a=3 This works. Since the correct answer must include I, eliminate B. II: b=2 Plugging b=2 into (ab)²+3ab-18 = 0, we get: 4a²+6a-18 = 0 2a²+3a-9 ...”
June 18, 2019
GMATGuruNY posted a reply to If the average (arithmetic mean) of seven consecutive in the Problem Solving forum
“For any set of consecutive integers, average = median. Let the 7 integers be 1, 2, 3, 4, 5, 6, 7. Since k+2 = average = median = 4, k=2. Product of the greatest and least = 7*1 = 7. The correct answer must yield 7 when k=2. Only C works: k² + 4k - 5 = 2² + (4*2) - 5 = 7 The correct ...”
June 17, 2019
GMATGuruNY posted a reply to In how many different ways can 3 fiction books and 3 in the Problem Solving forum
“Case 1: The 3 fiction books appear to the left of the 3 nonfiction books Number of ways to arrange the 3 fiction books = 3! = 6 Number of ways to arrange the 3 nonfiction books = 3! = 6 To combine these options, we multiply: 6*6 = 36 Case 2: The 3 nonfiction books appear to the left of the 3 ...”
June 17, 2019
GMATGuruNY posted a reply to Is x<0? 1) x^3+1<0 2) x^3+2x^2+x+2=0 in the Data Sufficiency forum
“Statement 1: x³ + 1 < 0 x³ < -1 The resulting inequality will hold true only if x < 0. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: x³ + 2x² + x + 2 = 0 x²(x+2) + (x+2) = 0 (x+2)(x²+1) = 0 The blue factor is equal to 0 if x=-2. It is not possible ...”
June 17, 2019
GMATGuruNY posted a reply to How many rectangles can be formed by connecting the grid poi in the Problem Solving forum
“https://i.postimg.cc/k681TSrJ/lattice-six-by-five.png To form a rectangle, we must combine a HORIZONTAL LENGTH with a VERTICAL LENGTH: Horizontal length: Number of ways to choose a horizontal length of 1: AB, BC, CD, DE, EF, FG = 6 Number of ways to choose a horizontal length of 2: AC, BD, ...”
June 17, 2019
GMATGuruNY posted a reply to If a fair 6-sided die is rolled three times, what is the in the Problem Solving forum
“P(exactly n times) = P(one way) * all possible ways. Let T = 3 and N = not 3. P(one way): One way to get exactly one 3: TNN. P(T on the 1st roll) = 1/6. (Of the 6 possible rolls, one is 3.) P(N on the 2nd roll) = 5/6. (Of the 6 possible rolls, five are not 3.) P(N on the 3nd roll) ...”
June 16, 2019
GMATGuruNY posted a reply to 10^25 – 560 is divisible by all of the following EXCEPT: in the Problem Solving forum
“RULE: MULTIPLE OF X + MULTIPLE OF X = MULTIPLE OF X MULTIPLE OF X + NON-MULTIPLE OF X = NON-MULTIPLE OF X For an integer to be divisible by 3, its digit sum must be a multiple of 3. 10²⁵ - 560 = (100000...) - (560) = 99999...440 Sum of the digits = (9+9+9+9+9...) + (4+4+0) = (multiple ...”
June 16, 2019
GMATGuruNY posted a reply to At a certain picnic, each of the guests was served either a in the Data Sufficiency forum
“Let D = the double-scoop guests and S = the single-scoop guests. What is value of D? Statement 1: Since 60% received a double-scoop, the remaining 40% received a single scoop. Thus: D/S = 60%/40% = 3/2 No way to solve for D. INSUFFICIENT. Statement 2: Since the D double-scoop guests ...”
June 15, 2019
GMATGuruNY posted a reply to A set of 15 different integers has median of 25 and a range in the Problem Solving forum
“Range = biggest - smallest. Thus: 25 = biggest - smallest. Smallest = biggest - 25. We can plug the answer choices into the equation above. Since we need the greatest possible integer that could be in the set, we should start with the greatest answer choice. Answer choice E: 50 Smallest ...”
June 15, 2019
GMATGuruNY posted a reply to Mixture problem in the Problem Solving forum
“2 liters of 25% solution are combined with 6 liters of 40% solution. Average percentage for the entire 8 liters = (2*25 + 6*40)/8 = 290/8 = 36.25. The closest answer is C. Alligation approach: Let V1 and V2 = the two vessels and M = the mixture. Step 1: Plot the three percents on a ...”
June 15, 2019
GMATGuruNY posted a reply to It is known that (1.1)^{17} is approximately equal to 5.05. in the Problem Solving forum
“1,1¹⁷ ≈ 5 (1.1¹⁷)³ ≈ 5³ 1.1⁵¹ ≈ 125 Thus: 1.1⁵⁰ = a bit less than 125 The correct answer is D.”
June 12, 2019
GMATGuruNY posted a reply to sum of these 24 integers? in the Problem Solving forum
“For any set that is SYMMETRICAL ABOUT THE MEDIAN: sum = (count)(median) The set is composed of integers in the following ranges: 1234...1432 2134...2431 3124...3421 4123...4321. Each range contains the same number of integers. Thus, the median of the set is equal to the average of ...”
June 11, 2019
GMATGuruNY posted a reply to In a certain deck of cards in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the least and greatest integers on the cards. D: least = 4, greatest = 14 (14)(next larger integer) = 14*15 = 210. Too big, since each possible product must be less than 200. Implication: The greatest integer must be LESS THAN 14. Eliminate ...”
June 11, 2019
GMATGuruNY posted a reply to Is x^3-x^2+x-1 > 0? in the Data Sufficiency forum
“A critical point occurs when the two sides of an equality are EQUAL. To determine the ranges where the left side is GREATER than the right side, test one value to the left and right of each critical point. x³ - x² + x - 1 > 0? x²(x-1) + (x-1) > 0 (x-1)(x²+1) > 0 The two sides are ...”
June 11, 2019
GMATGuruNY posted a reply to To celebrate a colleague's retirement, the T coworkers in an in the Problem Solving forum
“The T coworkers in an office agreed to share equally the cost of a catered lunch. The lunch costs a total of X dollars. Let X=5 and T=5, implying that the original cost per worker = 5/5 = $1. S of the coworkers fail to pay their share. Which of the following represents the additional amount, ...”
June 11, 2019
GMATGuruNY posted a reply to When the integer n is divided by 6, the remainder is 3, Whic in the Problem Solving forum
“When the integer n is divided by 6, the remainder is 3. When we are given this wording, the smallest option for n is THE REMAINDER ITSELF. Test n=3 in the answer choices: (A) n – 3 = 3-3 = 0 (B) n + 3 = 3+3 = 6 (C) 2n = 2*3 = 6 (D) 3n = 3*3 = 9 (E) 4n = 4*3 = 12 Only D is not a ...”
June 10, 2019
GMATGuruNY posted a reply to A real estate investment firm began the year with 80% of its in the Problem Solving forum
“Let the total investment = $1000, implying that commercial holdings = 80% of 1000 = $800 and that residential holdings = 1000-800 = $200. Since the total $1000 investment grows by 3.5%, the total growth = 3.5% of 1000 = $35. Since the $800 in commercial holdings grows by 7%, the growth in ...”
June 9, 2019
GMATGuruNY posted a reply to In order to conserve the energy and heat in the Sentence Correction forum
“A: reducing the rate at which they burn energy so that it is 25 percent lower Since the penguins are REDUCING THE RATE, we know from context that it refers to the rate, conveying that THE RATE is lower. Regardless, an answer choice may be eliminated for pronoun ambiguity only if an alternate ...”
June 9, 2019
GMATGuruNY posted a reply to Ann deposited money into two new accounts, A and B. Account in the Data Sufficiency forum
“What is the value of 0.08B - 0.05A? Statement 1: B-A = 200 B = A+200 Case 1: A = $100 and B=$300, with the result that 0.08B - 0.05A = 0.08(300) - 0.05(100) = 24-5 = 19 Case 2: A = $200 and B=$400, with the result that 0.08B - 0.05A = 0.08(400) - 0.05(200) = 32-10 = 22 Since 0.08B-0.05A ...”
June 9, 2019
GMATGuruNY posted a reply to The number line shown contains three points R, S, and T, in the Problem Solving forum
“Let R=-3, S=3 and T=6, implying that r=|-3|=3, s=|3|=3, and t=|6|=6. Average of R, S, and T = (-3+3+6)/3 = 2. The correct answer must yield 2 when r=3, s=3 and t=6. Only E works: (s + t - r)/3 = (3+6-3)/3 = 6/3 = 2 The correct answer is E.”
June 4, 2019
GMATGuruNY posted a reply to The principal feature of the redesigned checks is a series o in the Sentence Correction forum
“In the OA, the list of instructions includes THREE TYPES OF REMINDERS: a reminder TO WATCH a reminder TO COMPARE a reminder TO VIEW In option 2, the list of instructions seems to include the following three nouns: REMINDERS COMPARING VIEWING Thus, the intended meaning is not conveyed in ...”
June 3, 2019
GMATGuruNY posted a reply to Two pieces of fruit are selected out of a group of 8 pieces in the Data Sufficiency forum
“What is the value of P(BB)? Statement 1: From 8 pieces of fruit, the probability of picking an apple = A/8. After 1 of the A apples has been picked, the number of remaining apples = A-1. From the 7 remaining pieces of fruit, the probability of picking one of the A-1 remaining apples = ...”
June 3, 2019
GMATGuruNY posted a reply to The vertices of a rectangle in the standard (x,y) coordinate in the Problem Solving forum
“To partition the rectangle into equal areas, the line must pass through the CENTER of the rectangle. To determine the x-coordinate of the center, take the average of the x-coordinates that form the base: (0+7)/2 = 3.5. To determine the y-coordinate of the center, take the average of the ...”
June 1, 2019
GMATGuruNY posted a reply to 10 factories, working for h hours per day, can produce P in the Problem Solving forum
“When the factories work for h hours per day, P cars are produced every 5 days, with the result that 2P cars are produced every 10 days. If the daily work-hours are CUT IN HALF -- to h/2 hours per day -- the number of days required for 2P cars will DOUBLE to 20. Since the time for 2P cars increases ...”
June 1, 2019
GMATGuruNY posted a reply to Being a United States citizen since 1988 and born in Calcutt in the Sentence Correction forum
“One purpose of the present perfect -- has/have + VERBed -- is to express a past action that affects the present. OA: Bharati Mukherjee...has lived in England and Canada. Conveyed meaning: At some time in the past, Bharati Mukherjet lived in England and Canada, and this past action somehow ...”
May 31, 2019
GMATGuruNY posted a reply to If xy≠0, and 60% of x equals 87.5% of y, what is the value in the Problem Solving forum
“60x = 87.5y 120x = 175y 120(x/y) = 175 12(x/y) = 17.5 The correct answer is D.”
May 30, 2019
GMATGuruNY posted a reply to Last year, the price of a jar of peanut butter at a certain in the Problem Solving forum
“The price of a jar of peanut butter at a certain store was P dollars and the price of a jar of jelly at the same store was J dollars, where J=2P. Let P = 10 and J = 20 This year, the price of peanut butter increased by 20% and the price of jelly decreased by 20% New P = 10 + (20% of 10) = 10 + ...”
May 29, 2019
GMATGuruNY posted a reply to In the figure above, \(AB\) is perpendicular to \(BC\) and in the Problem Solving forum
“Let ∆ABD and ∆CBD each be a 45-45-90 triangle with sides 1, 1 and √2: https://i.postimg.cc/JGVTHJg1/two-45-45-90-triangles.png For the figure above, only option B is true: 1/BD² = 1/BC² + 1/AB² 1/1² = 1/√2² + 1/√2² 1 = 1/2 + 1/2 1 = 1 The correct answer is B.”
May 29, 2019
GMATGuruNY posted a reply to GMAT prep question-Confusing one ! in the Sentence Correction forum
“To refer to a noun that takes a SINGULAR verb, we use amount. To refer to a noun that takes a PLURAL verb, we use number. A and C: in terms of flights, an equal amount Here, amount cannot serve to refer to flights (a noun that takes a plural verb). Eliminate A and C. E: an equal number as ...”
May 29, 2019
GMATGuruNY posted a reply to if x and y are positive , is 4x>3y? in the Data Sufficiency forum
“Since y is POSITIVE, the inequalities can safely be divided by y. 4x > 3y x > (3/4)y x/y > 3/4 Question stem, rephrased: Is x/y > 3/4? Statement 1: x > y-x 2x > y 2(x/y) > 1 x/y > 1/2 Case 1: x/y = 2/3 In this case, x/y < 3/4, so the answer to the ...”
May 28, 2019
GMATGuruNY posted a reply to A certain fruit stand sold apples for $0.70 each and bananas in the Problem Solving forum
“Consider the following equation: 2x + 3y = 30. If x and y are nonnegative integers, the following solutions are possible: x=15, y=0 x=12, y=2 x=9, y=4 x=6, y=6 x=3, y=8 x=0, y=10 Notice the following: The value of x changes in increments of 3 (the coefficient for y). The value ...”
May 28, 2019
GMATGuruNY posted a reply to probability in the Problem Solving forum
“3 wins and 2 losses = WWWLL. One way to determine the number of ways to get 3 wins is to count the number of ways to arrange the 5 letters WWWLL. The number of ways to arrange 5 elements = 5!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of ...”
May 27, 2019
GMATGuruNY posted a reply to in old problem.. in other point.. in the Sentence Correction forum
“An ABSOLUTE PHRASE refers to the preceding subject. COMMA + APPOSITIVE serves to explain or define the nearest preceding noun or noun phrase. B and C: The computer company...will purchase the color-printing division of a rival company for $950 million, a part of a deal... Here, the modifier in ...”
May 27, 2019
GMATGuruNY posted a reply to A bowl contains equal numbers of red, orange, green, blue, in the Problem Solving forum
“10 Let R=O=G=B=Y=20, for a total of 100 marbles. Kaz eats all of the green candies and half of the orange ones. R=20, O=10, G=0, B=20, Y=20 He eats half of the remaining pieces of each color. R=10, O=5, G=0, B=10, Y=10 He eats red and yellow candies in equal proportions until the total ...”
May 26, 2019
GMATGuruNY posted a reply to If a/b<c/d & bd < 0, which of the following inequa in the Problem Solving forum
“In I, II and III, test the following case: a=c=d=1 and b=-1, with the result that a/b < c/d and bd < 0. I: ad-bc < 0 Since ad=1*1=1 and bc=-1*1=-1, we get: 1 - (-1) < 0 2 < 0 Not true. Eliminate A and D, each of which include I. II: bc-ad > 0 Since bc=-1*1=-1 abd ...”
May 26, 2019
GMATGuruNY posted a reply to A husband and wife can complete a certain task in 1 and 2 in the Data Sufficiency forum
“Let the job = 12 units. Dividing the four given times into the 12-unit job, we get the following hourly rates: Husband:Wife:Rae:Herman = (12 per hour): (6 per hour) : (3 per hour) : (2 per hour) (Husband + Wife) : (Rae + Herman) = (12+6 per hour) : (3+2 per hour) Couple : Children = 18:5 ...”
May 24, 2019
GMATGuruNY posted a reply to A jar contains 8 red marbles and \(y\) white marbles. in the Data Sufficiency forum
“Test the THRESHOLDS and try EXTREMES. Here, the THRESHOLDS are y=8 and y=4. Statement 1: y≤8 Case 1: 8 white marbles, 8 red marbles P(RR) = 8/16 * 7/15 = 7/30. P(one of each color): P(RW) = 8/16 * 8/15 = 8/30. Since RW can be reversed to WR, we multiply by 2: 2(8/30) = 16/30. In ...”
May 23, 2019
GMATGuruNY posted a reply to Robots X, Y, and Z each assembled components at their in the Data Sufficiency forum
“Let X = X''s rate, Y = Y''s rate, and Z = Z''s rate. r(x) = the ratio of X''s rate to Z''s rate = X/Z. r(y) = the ratio of Y''s rate to Z''s rate = Y/Z. Note: X, Y and Z all represent rates and thus must be POSITIVE. Statement 1: r(x) < r(y) In other words: X/Z < Y/Z. Since ...”
May 23, 2019
GMATGuruNY posted a reply to In the diagram above, line BC touches the circle at point C in the Data Sufficiency forum
“To determine the area of the circle, we need to know its radius. Question stem, rephrased: What is the value of r? A radius drawn to a tangent line forms a RIGHT ANGLE. Thus, angle OCB is a right angle, with the result that triangle OCB is a right triangle. In right triangle OCB, OB=r, BC=35, ...”
May 23, 2019
GMATGuruNY posted a reply to NNN in the Critical Reasoning forum
“Consider the following case: The networks airs over one hundred programs focused largely on the opinions of its viewers. The NUMBER of programs tells us nothing about the NATURE of the opinions (whether they are liberal or conservative) or about the network''s REACTION to these opinions (whether ...”
May 23, 2019
GMATGuruNY posted a reply to NNN in the Critical Reasoning forum
“The two statements together serve to form the conclusion of the programming director. A premise is a FACT not in dispute. A conclusion is an OPINION that CAN be disputed. Only one FACT is presented in the passage: When a liberal news personality was recently added to the Network, an additional ...”
May 22, 2019
GMATGuruNY posted a reply to A conveyor belt moves bottles at a constant speed of 120 in the Data Sufficiency forum
“Given rate: 120 centimeters per second. Since the statements are in terms of MINUTES, calculate the number of minutes required to move the bottle 90 meters: 90 meters * (100 centimeters)/(1 meter) * (1 second)/(120 centimeters) * (1 minute)/(60 seconds) = (90)/(12*6) = 15/12 = 5/4 = 1.25 minutes ...”
May 22, 2019
GMATGuruNY posted a reply to ps 500 test27 #16 in the Problem Solving forum
“John and Mary were each paid x dollars in advance to do a certain job together. John worked on the job for 10 hours. Mary worked 2 hours less than John. Since a total of 18 hours are worked -- 10 hours by John, 8 hours by Mary -- let x=18. Since John and Mary are each given $18 in advance, the ...”
May 21, 2019
GMATGuruNY posted a reply to Is x > 0? in the Data Sufficiency forum
“Note: |a|² = a² |a+b|² = (a+b)² Statement 1: Since an absolute value cannot be negative, both sides of the inequality must be nonnegative, allowing us to safely square it: (|x| + |y|)² > |x + y|² |x|² + |y|² + 2|x||y| > (x+y)² x² + y² + 2|x||y| > x² + y² + 2xy |x||y| ...”
May 20, 2019
GMATGuruNY posted a reply to If f(x)=x^4+4x^2+7, f(x)=g(x)^2+3 and g(x) > 0, then g(x) in the Problem Solving forum
“Let x=0, with the result that f(x) = 0+0+7 = 7. Remembering that g(x)>0 and plugging f(x)=7 into f(x)=g(x)²+3, we get: 7 = g(x)²+3 4 = g(x)² g(x) = 2 Since the question stem asks for the value of g(x), the correct answer must yield 2 when x=0. Only B works: x²+2 = 0²+2 = 2 The ...”
May 20, 2019
GMATGuruNY posted a reply to (n+1)!f(n) = (n-1)!. What is the value of f(1) + f(2) + … in the Problem Solving forum
“f(n) = (n-1)!/(n+1)! f(1) = 0!/2! = 1/2 f(2) = 1!/3! = 1/6 f(3) = 2!/4! = 1/12 f(4) = 3!/5! = 1/20 f(1) + f(2) = 1/2 + 1/6 = 2/3 f(1) + f(2) + f(3) = 2/3 + 1/12 = 3/4 f(1) + f(2) + f(3) + f(4) = 3/4 + 1/20 = 4/5 The sum of the first 2 terms = 2/3. The sum of the first 3 terms = 3/4. ...”
May 17, 2019
GMATGuruNY posted a reply to A 3-digit positive integer consists of non zero digits. If in the Problem Solving forum
“Alternate approach: Integers with exactly 2 digits the same = Total integers - Integers with all 3 digits the same - Integers with all 3 digits different. Total integers: Number of options for the hundreds digit = 9. (Any digit but 0.) Number of options for the tens digit = 9. (Any digit ...”
May 16, 2019
GMATGuruNY posted a reply to What is the value of x? in the Data Sufficiency forum
“Statement 1: Squaring both sides, we get: x² + y² + 2xy = x² + y² - 2xy 4xy = 0 xy = 0 Case 1: x=0, with the result that y can be any value Case 2: y=0, with the result that x can be any value Since Case 2 allows x to be any value, INSUFFICIENT. Statement 2: Here, y can be any ...”
May 16, 2019
GMATGuruNY posted a reply to Each of A, B and C represents a one-digit integer. AB and BA in the Problem Solving forum
“325 = 100*3 + 10*2 + 5 648 = 100*6 + 10*4 + 8 Generally: Three-digit integer XYZ = 100X + 10Y + Z Since BA + AB + AB = CAA, we get: (10B+A) + (10A+B) + (10A+B) = 100C + 10A + A 12B + 21A = 100C + 11A 12B + 10A = 100C 12B + 10A = MULTIPLE OF 100 Since B and A are digits, the left side will ...”
May 16, 2019
GMATGuruNY posted a reply to The federal immigration station on Ellis Island - GMATPrep in the Sentence Correction forum
“Yes. E: Of all immigrants...the station processed nearly three quarters of them. Here, the red modifier is redundant with the blue modifier. Generally, COMMA + having + VERBed serves to express an action that happens before the action in the preceding clause. E: The federal immigration ...”
May 15, 2019
GMATGuruNY posted a reply to In the xy-coordinate system, rectangle ABCD is inscribed in the Problem Solving forum
“x²+y² = r² is the equation for a circle with its center at the origin and a radius of r. Thus, x²+y² = 25 is a circle with a center at the origin and a radius of 5. The information in the prompt yields the following figure: https://i.postimg.cc/xJCgjxbd/rectangle-in-circle.png OB is a ...”
May 15, 2019
GMATGuruNY posted a reply to A retail store employs only clerks and managers and the in the Problem Solving forum
“Last year''s payroll = (number of employees)(average hourly wage) = 20*13 = 260. This year 4 clerks are hired, increasing the number of employees to 24. Since the average hourly wage this year = 14, we get: This year''s payroll = (number of employees)(average hourly wage) = 24*14 = 336. ...”
May 14, 2019
GMATGuruNY posted a reply to According to public health officials in the Sentence Correction forum
“Incorrect: More babies were born in 1900 than they were born in 1800. Here, the usage of they implies that the SAME BABIES born in 1900 were also born in 1800 -- a nonsensical meaning. Generally: When a comparison begins with MORE/FEWER + SUBJECT + VERB, the implied clause after than should NOT ...”
May 13, 2019
GMATGuruNY posted a reply to An auto dealer sells each car at either $20,000 or $30,000. in the Data Sufficiency forum
“Statements combined: Case 1: 30 $30,000 cars are marked up 30%'' 20 $20,000 cars are marked up 20% Case 2: 10 $30,000 cars are marked up 30% 20 $20,000 cars are marked up 30% 20 $30,000 cars are marked up 20% In Case 1, the more expensive $30,000 cars are all sold at the higher profit ...”
May 13, 2019
GMATGuruNY posted a reply to OG 13 #9 in the Sentence Correction forum
“When a statistic decreases in value, we use lower rather than less. Incorrect: The temperature was less in the second experiment than in the first. Correct: The temperature was lower in the second experiment than in the first. Most of the country’s biggest daily newspapers had lower ...”
May 12, 2019
GMATGuruNY posted a reply to In how many different ways can a soccer team finish the in the Problem Solving forum
“Alternate approach: There are 6 slots in the season: 3 wins, 2 losses and 1 draw. From the 6 slots, the number of ways to choose 3 to be occupied by the 3 wins = 6C3 = (6*5*4)/(3*2*1) = 20. From the 3 remaining slots, the number of ways to choose 2 to be occupied by the 2 losses = 3C2 = ...”
May 11, 2019
GMATGuruNY posted a reply to OG 13 #9 in the Sentence Correction forum
“Here, greater serves to modify not costs but PROPORTION. Conveyed meaning: The PROPORTION in the presidential campaign of 1992 was greater than the PROPORTION in any previous election. When comparing elements with regard to WEIGHT, we generally use not lower but LESS. Adam weighs LESS than ...”
May 11, 2019
GMATGuruNY posted a reply to If a, b, and c are positive integers, what is the remainder in the Data Sufficiency forum
“Statement 1: No information about b. INSUFFICIENT. Statement 2: No information about a. INSUFFICIENT. Statements combined: Case 1: c=1, with the result that a=1³=1 and b=(1-2)³=-1 In this case, (a-b)/6 = C.”
May 11, 2019
GMATGuruNY posted a reply to If a, b, and c are positive integers, what is the remainder in the Data Sufficiency forum
“Statement 1: No information about b. INSUFFICIENT. Statement 2: No information about a. INSUFFICIENT. Statements combined: Case 1: c=1, with the result that a=1³=1 and b=(1-2)³=-1 In this case, (a-b)/6 = C.”
May 11, 2019
GMATGuruNY posted a reply to According to surveys by the National Institute on Drug Abuse in the Sentence Correction forum
“Proposed revision: as many young adults as the 1997 survey reported Conveyed meaning: The 1997 survey reported many young adults. This meaning seems illogical. The 1997 survey reported a NUMBER. It did not report the young adults themselves.”
May 10, 2019
GMATGuruNY posted a reply to Ellipsis question in the Sentence Correction forum
“OA: Today, the same amount of acreage produces twice as many apples as it did in 1910. The phrase in blue conveys that the amount of acreage producing apples today is the SAME as the amount that produced apples in 1910. For example: If 100 acres produced apples in 1910, then 100 acres are ...”
May 10, 2019
GMATGuruNY posted a reply to An art gallery has only paintings and sculptures. Currently, in the Problem Solving forum
“This is an EITHER/OR group problem. Every piece of art is EITHER a painting OR a sculpture. Every piece of art is EITHER displayed OR not displayed. For an EITHER/OR group problem, we can use a GROUP GRID (also known as a double-matrix) to organize the data. Let P = paintings, S = ...”
May 10, 2019
GMATGuruNY posted a reply to The sum of two numbers is 1 and their product is -1. What is in the Problem Solving forum
“x³ + y³ = (x+y)(x²+y²-xy) Since x+y=1, we get: (x+y)² = 1² x² + y² + 2xy = 1 Substituting xy=-1 into x² + y² + 2xy = 1, we get: x² + y² + 2(-1) = 1 x² + y² = 3 Substituting x+y=1, x²+y²=3 and xy=-1 into x³ + y³ = (x+y)(x²+y²-xy), we get: x³ + y³ = (1)(3-(-1)) = ...”
May 8, 2019
GMATGuruNY posted a reply to According to surveys by the National Institute on Drug Abuse in the Sentence Correction forum
“Correct! The OA to SC71 in the OG11 includes a similar construction: The cameras of the Voyager II spacecraft detected six small, previously unseen moons circling Uranus, doubling...the number of satellites now known to orbit the distant planet.”
May 7, 2019
GMATGuruNY posted a reply to GMATPrep SC in the Sentence Correction forum
“Here, much and the increase are redundant, since both words refer to an amount. Proposed revision: The number of people flying first class on domestic flights rose sharply in 1990, twice the increase of the previous year. Implied comparison: The NUMBER OF PEOPLE flying in 1990 was twice ...”
May 7, 2019
GMATGuruNY posted a reply to If each child in a group of children received either one or in the Data Sufficiency forum
“Let x = the number of children receiving 2 candies each and y = the number of children receiving 1 candy each. Thus: Total number of candies = 2x + y. Question stem, rephrased: What is the value of x? Statement 1: Of every 4 children, 1 receives 2 candies and 3 each receive 1 candy. ...”
May 7, 2019
GMATGuruNY posted a reply to Anthony and Michael sit on the six-member board of directors in the Problem Solving forum
“A 3-person committee that includes Michael will be composed of Michael and two other people chosen from the remaining five members. From 5 members, the number of ways to choose 2 = 5C2 = 10. Of these 10 pairs, the number that will include Anthony = 4. (Since there are 4 other people who could ...”
May 7, 2019
GMATGuruNY posted a reply to A bucket full worns in the Problem Solving forum
“Let the number of worms = 60. Since the rat eats 1/6 of the 60 worms -- in other words, 10 worms -- in 5 hours, the rat''s rate = w/t = 10/5 = 2 worms per hour. 1/4 of the 60 worms = 60/4 = 15 worms. Since the rat''s rate = 2 worms per hour, the time for the rat to eat 15 worms = w/r = 15/2 = 7.5 ...”
May 7, 2019
GMATGuruNY posted a reply to A book has 1000 pages numbered 1, 2, 3, …, and so on. How in the Problem Solving forum
“Ignore page 1000, since it does not include the digit 2. To make the calculation easier, consider the remaining pages numbered as 3-digit integers, beginning with 000 and ending with 999: 000, 001, 002...997, 998, 999 There are 1000 options between 000 to 999, inclusive. Since each option is ...”
May 7, 2019
GMATGuruNY posted a reply to The equation (M + 6)/36 = (p – 7)/21 relates two temperatu in the Problem Solving forum
“If M=30 and P=28, both sides of (M + 6)/36 = (P – 7)/21 are equal to 1. The correct answer must yield a valid equation for M=30 and P=28. When the question stem includes the phrase "which of the following," the correct answer is likely to be D or E. E: M = (12/7)P – 18 If M=30 ...”
May 6, 2019
GMATGuruNY posted a reply to What is the remainder when the product of the first 10 prime in the Problem Solving forum
“What is the remainder when 30 is divided by 4? One approach: 1. Break the dividend 30 into factors: 30 = 5*6 2. Divide the divisor 4 into each factor: 5/4 = 1 R1, 6/4 = 1 R2 3. Multiple the resulting remainders: 1*2 = 2 Step 3 indicates that 30 divided by 4 will yield a remainder of 2. ...”
May 6, 2019
GMATGuruNY posted a reply to If a jury of 12 people is to be selected randomly from a in the Problem Solving forum
“Question rephrased: What is the probability that at least 8 men will be selected to serve on the 12-member jury? P(good outcome) = 1 - P(bad outcome). Here, a BAD outcome means selecting a jury with FEWER than 8 men. Of the 10 men and 5 women in the jury pool, 3 people must be selected NOT ...”
May 5, 2019
GMATGuruNY posted a reply to 7, 9, 6, 4, 5, x If x is a number in the list above in the Data Sufficiency forum
“Given numbers in ascending order: 4, 5, 6, 7, 9 Statement 1: Smallest 3 numbers are 4, 5, and 6. Greatest 3 numbers are 7, 9 and x, where x is any number greater than 7. Thus: Median = average of the 2 middle numbers =(6+7)/2 = 6.5. SUFFICIENT. Rule: For any set that is SYMMETRICAL ...”
May 4, 2019
GMATGuruNY posted a reply to Romeo and Juliet play a dice game in which the two in the Problem Solving forum
“Let P(R) = the probability that Romeo wins and P(J) = the probability that Juliet wins. Since there are only two possible outcomes -- either Romeo wins or Juliet wins -- we get: P(R) + P(J) = 1 Probability that Romeo wins on the first roll = 1/6 Probability that Romeo wins on the third roll ...”
May 3, 2019
GMATGuruNY posted a reply to Tickets for all but 100 seats in a 10,000-seat stadium were in the Problem Solving forum
“If all 10,000 tickets are sold, we get: 20% sold for $1 each = 2000*1 = 2,000 80% sold for $2 each = 8000*2 = 16,000 Total revenue = 2000+16000 = 18,000 Since 100 tickets are not actually sold, the total revenue must be a bit less than 18,000. The correct answer is B.”
May 2, 2019
GMATGuruNY posted a reply to Tony owns six unique matched pairs of socks. All twelve sock in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the minimum number of socks that must be pulled. When the correct answer choice is plugged in, the probability of NOT picking a matching pair will be LESS than 1/2 (implying that the probability of picking a matching pair will be MORE than 1/2). Since we ...”
May 2, 2019
GMATGuruNY posted a reply to Tony owns six unique matched pairs of socks. All twelve sock in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the minimum number of socks that must be pulled. When the correct answer choice is plugged in, the probability of NOT picking a matching pair will be LESS than 1/2 (implying that the probability of picking a matching pair will be MORE than 1/2). Since we ...”
May 2, 2019
GMATGuruNY posted a reply to Train A leaves the station at 5:00, and travels north at 50 in the Data Sufficiency forum
“Statement 1: From 5pm to 6pm, A travels on its own for 1 hour at a rate of 50 mph, with the result that A travels ahead 50 miles. Since B''s rate is unknown, we cannot determine when B catches up to A. INSUFFICIENT. Statement 2: Since A''s 50-mph rate is 5/6 of B''s rate, we get: 50 = ...”
May 1, 2019
GMATGuruNY posted a reply to x^2 + 4x + 1 = 0. What is the value of x^2 + 1/x^2? in the Problem Solving forum
“x² + 4x + 1 = 0 Dividing both sides by x, we get: (x² + 4x + 1)/x = 0/x x + 4 + 1/x = 0 x + 1/x = -4 Squaring both sides, we get: (x + 1/x)² = (-4)² x² + 1/x² + 2(x)(1/x) = 16 x² + 1/x² + 2 = 16 x² + 1/x² = 14 The correct answer is C.”
May 1, 2019
GMATGuruNY posted a reply to For all his professed disdain of such activities, Auden was in the Sentence Correction forum
“When a sentence begins with for all + POSSESSIVE, for all = DESPITE. OA: For all his professed disdain of such activities, Auden was an inveterate literary gossip. Conveyed meaning: Despite his professed disdain of such activities, Auden was an inveterate literary gossip. E: In spite of ...”
April 30, 2019
GMATGuruNY posted a reply to Is x+y>0? in the Data Sufficiency forum
“Statement 1: Here, x and y must have the SAME SIGN. If x and y are both positive, then x+y > 0. If x and y are both negative, then x+y < 0. INSUFFICIENT. Statement 2: The inequality implies that x and y are both NONZERO. Since the square of a nonzero value must be positive, we can ...”
April 30, 2019
GMATGuruNY posted a reply to Last year, the average price of eight different products in the Data Sufficiency forum
“We can determine this year''s average price if we know the difference between this year''s revenue and last year''s. Statements combined: Case 1: Last year the 5 products in Statement 1 had an average price of $10, for a total of $50 in revenue In this case, the increase in revenue yielded by ...”
April 30, 2019
GMATGuruNY posted a reply to A basketball coach has won 65 percent of the 400 games she in the Problem Solving forum
“Total games = (400 games already played) + (100 additional games) = 500. Required number of wins = 70% of 500 = 350. Current number of wins = 65% of 400 = 260. Additional wins needed = 350-260 = 90. The correct answer is D.”
April 30, 2019
GMATGuruNY posted a reply to What is the remainder when 1044*1047*1050*1053 is in the Problem Solving forum
“What is the remainder when 30 is divided by 4? One approach: 1. Break the dividend 30 into factors: 30 = 5*6 2. Divide the divisor 4 into each factor: 5/4 = 1 R1, 6/4 = 1 R2 3. Multiple the resulting remainders: 1*2 = 2 Step 3 indicates that 30 divided by 4 will yield a remainder of 2. ...”
April 30, 2019
GMATGuruNY posted a reply to What is the units digit of the number z? in the Data Sufficiency forum
“Statements combined: Case 1: z=19, with the result that z is between both 17 and 20 and 18 and 21 In this case, the units digit of z is 9. Case 2: z=18.1, with the result that z is between both 17 and 20 and 18 and 21 In this case, the units digit of z is 8. Since the units digit can be ...”
April 28, 2019
GMATGuruNY posted a reply to The number line shown contains three points R, S, and T in the Problem Solving forum
“Let R=-3, S=3 and T=6, implying that r=|-3|=3, s=|3|=3, and t=|6|=6. Average of R, S, and T = (-3+3+6)/3 = 2. The correct answer must yield 2 when r=3, s=3 and t=6. Only E works: (s + t - r)/3 = (3+6-3)/3 = 6/3 = 2 The correct answer is E.”
April 28, 2019
GMATGuruNY posted a reply to Peter and Tom shared the driving on a certain trip. in the Problem Solving forum
“Let the total distance = 5 miles and the time for each driver = 1 hour. Since Peter drives 2/5 of the total distance -- 2 miles -- in 1 hour, Peter''s speed = d/t = 2/1 = 2 miles per hour. Since Tom drives the remaining distance -- 3 miles -- in 1 hour, Tom''s speed = d/t = 3/1 = 3 miles per ...”
April 28, 2019
GMATGuruNY posted a reply to Ten theater students are to begin work on a set for a musica in the Problem Solving forum
“(50 days)/(60 days) = 5/6. To finish the job in 5/6 of the normal time, the crew requires 6/5 of the normal number of students -- an increase of 1/5: (1/5)(10) = 2 more students. The correct answer is A.”
April 27, 2019
GMATGuruNY posted a reply to OG Most of the country's biggest daily newspapers in the Sentence Correction forum
“Plural terms such as profits, revenues, costs, etc. refer to NUMERICAL VALUES. When comparing plural terms that refer to numerical values, we generally do not use more but instead use -ER comparatives such as higher, lower, greater, etc. Thus, the blue sentence above is correct; the red sentence ...”
April 26, 2019
GMATGuruNY posted a reply to Suppose x = a/b (b≠0). Which of following is equivalent to in the Problem Solving forum
“Let a=2 and b=1, with the result that x = a/b = 2/1 = 2 and that (a²+ab)/(a²+b²) = (4+2)/(4+1) = 6/5. The correct answer must yield 6/5 when x=2. Only A works: (x²+x)/(x²+1) = (4+2)/(4+1) = 6/5 The correct answer is A.”
April 25, 2019
GMATGuruNY posted a reply to Probability Question in the Problem Solving forum
“The approach above counts the following: Cases that include 11: 1122, 1133, 1144, 1155, 1166 Cases that include 22: 2211, 2233, 2244, 2255, 2266 Cases that include 33: 3311, 3322, 3344, 3355, 3366 Cases that include 44: 4411, 4422, 4433, 4455, 4466 Cases that include 55: 5511, 5522, ...”
April 25, 2019
GMATGuruNY posted a reply to On account of a law in the Sentence Correction forum
“The OA is correct because it contains no grammatical errors and conveys a logical meaning. OA: With the cost of wireless service plummeting, many people are now using their mobile phones. Here, the action in blue is accompanied by the plummeting cost of wireless service. This meaning is perfectly ...”
April 24, 2019
GMATGuruNY posted a reply to Probability Question in the Problem Solving forum
“All possible rolls: Since there are 6 number options for each roll, we get: 6*6*6*6 = 1296 Case 1: Exactly 2 rolls are the same (such as 1123) From 4 rolls, the number of ways to choose a pair to yield the same number = 4C2 = (4*3)/(2*1) = 6. Number options for this pair = 6. (Any of the 6 ...”
April 22, 2019
GMATGuruNY posted a reply to If j > 1, is integer j a prime number? in the Data Sufficiency forum
“Statements combined: Since dividing by 3 or 2 leaves a remainder of 1, j must be 1 more than a multiple of 3 and 2: j = (3*2)a + 1 = 6a + 1, where a is a positive integer Options for j: 7, 13, 19, 25... If j=7, then the answer to the question stem is YES. If j=25, then the answer to the ...”
April 21, 2019
GMATGuruNY posted a reply to From a group of 5 managers (Joon, Kendra, Lee, Marnie and in the Problem Solving forum
“Approach 1; P = (good pair)/(all possible pairs) Good pair = Marnie and Noomi = 1 option. All possible pairs = the number of ways to select 2 managers from 5 options = 5C2 = (5*4)/(2*1) = 10 options. Thus: P = 1/10 = 0.1 Approach 2: P(M or N is selected first) = 2/5. (Of the 5 managers, 2 ...”
April 21, 2019
GMATGuruNY posted a reply to While it costs about the same in the Sentence Correction forum
“Here, the phrase in blue implies that people were trying to drive on the freeway but that the process was made challenging by the rain. This meaning is logical. Here, the phrase in red implies that nuclear plants are trying to generate electricity but that the process is made more expensive ...”
April 20, 2019
GMATGuruNY posted a reply to Discussion of greenhouse effects has usually in the Sentence Correction forum
“An effect is a CHANGE brought about by an event. The Earth ALWAYS has a temperature. Since temperature does not constitute a change, it cannot be an effect. In the OA, EXTREMES are the change brought about by greenhouse emissions. This meaning is logical. The temperature of the Earth is not ...”
April 20, 2019
GMATGuruNY posted a reply to What is the value of |x|? in the Data Sufficiency forum
“Statement 1: Case 1: x=0, with the result that -|x| = - |0| = 0 In this case, |x| = 0. Case 2: x=-1, with the result that -|-1| = -1 In this case, |x| = 1. Since |x| can be different values, INSUFFICIENT. Statement 2: Thus, x=2 or x=-2. In each case, |x|=2. SUFFICIENT. The correct ...”
April 20, 2019
GMATGuruNY posted a reply to Mary's income is 60 percent more than Tim's income, and in the Problem Solving forum
“Let J=100. Since Tim''s income is 40% less than Juan''s, T = 100 - (40% of 100) = 100 - 40 = 60. Since Mary''s income is 60% greater than Tim''s, M = 60 + (60% of 60) = 60 + 36 = 96. What percent of Juan''s income is Mary''s income? M/J = 96/100 = 96%. The correct answer is C.”
April 20, 2019
GMATGuruNY posted a reply to Verb-ing doubt in the Sentence Correction forum
“NOUN + VERBing implies that the VERBing is a restrictive modifier. The purpose of a restrictive modifier is to SPECIFY the type of noun being discussed. Here, the restrictive modifier in blue implies the following: There are many types of planets. The sentence is not referring to all these ...”
April 18, 2019
GMATGuruNY posted a reply to If x and y are positive integers and in the Data Sufficiency forum
“Statement 1: x=2 \(2^y =2^{2y-3} \) Since each side has the same base, the two exponents must be equal: y = 2y-3 3 = y Since the values of x and y are known, the value of \(x^y\) can be determined. SUFFICIENT. Statement 2: Thus, x=2. Same information as in Statement 1. Since Statement ...”
April 17, 2019
GMATGuruNY posted a reply to There are 10 employees in an office. The table shows how in the Problem Solving forum
“List of 10 pet values implied by the chart: 0, 0, 1, 1, 1, 2, 2, 3, 3, 3 Since the answer choices are all 3 or greater, the addition of the manager''s pet value will yield the following list of 11 values: 0, 0, 1, 1, 1, 2, 2, 3, 3, 3, M Since the new average must be equal to the median value ...”
April 17, 2019
GMATGuruNY posted a reply to Computer-based activities in the Critical Reasoning forum
“In a strengthen CR, the OA SUPPORTS THE PASSAGE. In an inference CR, the PASSAGE SUPPORTS THE OA. Here, the OA supports the passage. The result is a strengthen CR. Since the OA supports the conclusion, its negation naturally will weaken the conclusion.”
April 16, 2019
GMATGuruNY posted a reply to OG Most of the country's biggest daily newspapers in the Sentence Correction forum
“This is the comparison conveyed by the green sentence above. Here, each blue portion has a subject (the company) and a verb (had) and thus constitutes a clause. The result is a logical comparison. This is the comparison implied by the incorrect red sentence above. The first blue portion ...”
April 16, 2019
GMATGuruNY posted a reply to Three salespeople, Dan, Matt, and Nicole, earned annual in the Problem Solving forum
“D:M:N = 3:5:8. The sum of the parts of the ratio = 3+5+8 = 16. The values in red indicate the following: Nicole''s fraction of the total = 8/16 = 1/2. Since Nicole''s $28,000 is 1/2 of the total, the total = $56,000. The correct answer is E.”
April 15, 2019
GMATGuruNY posted a reply to Together, 15 type A machines and 7 type B machines can in the Problem Solving forum
“Let the job = 44 units. Since 15A+7B take 4 hours to complete the 44-unit job, the rate for 15A+7B = w/t = 44/4 = 11 units per hour. Since 8B+15C take 11 hours to complete the 44-unit job, the rate for 8B+15C = w/t = 44/11 = 4 units per hour. Adding together 15A+7B=11 and 8B+15C=4, we get: ...”
April 15, 2019
GMATGuruNY posted a reply to Mark has fewer than 9 coins. Each coin is either a quarter in the Data Sufficiency forum
“Statement 1: 25Q + 10D = 170 5Q + 2D = 34 To minimize the number of coins, we must maximize the value of Q. If Q=6, then D=2, with the result that 5Q + 2D = (5*6) + (2*2) = 34. In this case, the total number of coins = 6+2 = 8. If the value of Q decreases, then the total number of coins ...”
April 15, 2019
GMATGuruNY posted a reply to 12^(1/2) + 108^(1/2) + 48^(1/2) = in the Problem Solving forum
“√12 + (√9 * √12) + (√4 * √12) = √12 + 3√12 + 2√12 = 6√12 = 6 * √4 * √ 3 = 12√3 The correct answer is A.”
April 15, 2019
GMATGuruNY posted a reply to If n is a positive integer greater than 6, what is the in the Data Sufficiency forum
“Approach 1: Since n is greater than 6, and the statements refer to n², make a list of perfect squares greater than 6²: n² = 49, 64, 81, 100, 121, 144, 169, 196, 225. Subtracting 1 from these values, we get the following options for n² - 1: n² - 1 = 48, 63, 80, 99, 120, 143, 168, 195, ...”
April 15, 2019
GMATGuruNY posted a reply to Which of the following is equivalent to in the Problem Solving forum
“Let x=2 and y=1, with the result that (x+y)/3 - (x-y)/4 = 1 - 1/4 = 3/4. The correct answer must yield 3/4 when x=2 and y=1. Only D works: (7y+x)/12 = (7*1 + 2)/12 = 9/12 = 3/4 The correct answer is D.”
April 15, 2019
GMATGuruNY posted a reply to In a certain office, 50 percent of the employees are college in the Data Sufficiency forum
“Let T = the total number of employees. Since 60% of the employees are over 40, we get: Over 40 = 0.6T 30% of those over 40 -- in other words, 30% of the expression in blue -- have master''s degrees. Thus: Over 40 with master''s = 0.3(0.6T). To calculate the value of the expression in ...”
April 14, 2019
GMATGuruNY posted a reply to Dwight and Mose decide to build a new barn on their farm, in the Problem Solving forum
“Every time Dwight does 1/4 of the remaining work, 3/4 of the work remains. Every time Mose does 1/6 of the remaining work, 5/6 of the work remains. When Mose starts his third shift, Dwight has completed 3 shifts, while Mose has completed 2 shifts. Thus, the remaining work at the start of Mose''s ...”
April 14, 2019
GMATGuruNY posted a reply to In a law firm, 72% of the employees are associates and 54% in the Problem Solving forum
“Let the total number of employees = 100, implying that the total number of associates = 72% of 100 = 72 and that the number of senior associates = 54% of 100 = 54. The prompt should make clear that every associate is either a junior associate or senior associate, yielding the following equation: ...”
April 14, 2019
GMATGuruNY posted a reply to A library branch originally contained 18360 volumes, 30% of in the Problem Solving forum
“Since the answer choices are PERCENTS, the total number of books can be ANY POSITIVE VALUE. 30% = 3/10, implying a denominator of 10. Let the total number of books = the product of the three denominators 10, 3 and 3 = 10*3*3 = 90. Since 30% of the books are fiction, the number of fiction books ...”
April 12, 2019
GMATGuruNY posted a reply to Heavy commitment by an executive in the Sentence Correction forum
“that-clause includes its own subject and verb and thus does not require an additional agent. In the blue that-clause above, the subject for will meet (verb) is a system of import relief laws. Since it is clear that A SYSTEM will meet the strategic needs, no additional agent is required. An ...”
April 11, 2019
GMATGuruNY posted a reply to Mary and Kate are running clockwise around a circular track in the Problem Solving forum
“Since Mary is behind Kate by 250 meters -- half the circumference of the track -- she will catch up to Mary when she has traveled 250 meters more than Kate. To catch up to Kate a second time, Mary must then travel one more lap than Kate -- in other words, 500 meters more than Kate. Implication: ...”
April 11, 2019
GMATGuruNY posted a reply to Heavy commitment by an executive in the Sentence Correction forum
“The bad weather makes it difficult to work outdoors. Here, the infinitive in blue is not immediately preceded by an agent: the sentence does not specify WHO is intended TO WORK. The implication is that the agent for the blue infinitive is not a specific person but people IN GENERAL, as follows: ...”
April 11, 2019
GMATGuruNY posted a reply to How many rectangles are found in the lattice below? in the Problem Solving forum
“https://i.postimg.cc/Z0xg3MXX/lattice.png To form a rectangle, we must combine as HORIZONTAL LENGTH with a VERTICAL LENGTH: Horizontal length: Number of ways to choose a horizontal length of 1: AB, BC, CD, DE, EF = 5 Number of ways to choose a horizontal length of 2: AC, BD, CE, DF = 4 ...”
April 9, 2019
GMATGuruNY posted a reply to If x is a positive integer, is the remainder 0 when in the Data Sufficiency forum
“\(3^x + 1\) will yield a remainder of 0 when divided by 10 if it has a units digit of 0. 3¹ --> units digit of 3. 3² --> units digit of 9. (Since the product of the preceding units digit and 3 = 3*3 = 9.) 3³ --> units digit of 7. (Since the product of the preceding units digit and ...”
April 9, 2019
GMATGuruNY posted a reply to If d is a positive integer and f is the product of the first in the Data Sufficiency forum
“30! = 30*29*28*....*3*2*1. Statement 1: To determine the greatest possible value for d, we need to know the number of 10''s contained within 30! Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of 30! will yield a 10. The prime-factorization of 30! is composed ...”
April 9, 2019
GMATGuruNY posted a reply to Last year, the price of a jar of peanut butter at a certain in the Problem Solving forum
“The price of a jar of peanut butter at a certain store was P dollars and the price of a jar of jelly at the same store was J dollars, where J=2P. Let P = 10 and J = 20 This year, the price of peanut butter increased by 20% and the price of jelly decreased by 20% New P = 10 + (20% of 10) = 10 + ...”
April 9, 2019
GMATGuruNY posted a reply to If the median and average (arithmetic mean) of a set of 4 di in the Data Sufficiency forum
“In ascending order, let the four numbers = a, b, c, d. Since the average of the 4 numbers = 10, we get: (a+b+c+d)/4 = 10 a+b+c +d = 40 Since the median of the 4 numbers = 10, we get: (b+c)/2 = 10 b+c = 20 Subtracting the blue equation from the red equation, we get: (a+b+c+d) - (b+c) = 40-20 ...”
April 8, 2019
GMATGuruNY posted a reply to Mixture A is 15 percent alcohol, and mixture B is 50 percent in the Problem Solving forum
“A = 15% alcohol B = 50% alcohol The MIXTURE of A and B = 30% alcohol To determine the ratio of A to B, use ALLIGATION -- a very efficient way to handle mixture problems. Step 1: Plot the 3 percentages on a number line, with the percentages for A and B (15% and 50%) on the ends and the ...”
April 7, 2019
GMATGuruNY posted a reply to A museum sold 30 tickets on Saturday. Some of the tickets so in the Data Sufficiency forum
“Let G = the number of general tickets. Since a total of 30 tickets are sold, the number of special exhibit tickets = 30-G. Since general tickets = $10 each and special exhibit tickets = $70 each, we get: Total revenue = 10G + 70(30-G) = 10G + 2100 - 70G = 2100 - 60G. Statement 1: 1570 < ...”
April 7, 2019
GMATGuruNY posted a reply to If 500 is the multiple of 100 that is closest to X and 400 in the Data Sufficiency forum
“Statements combined: Case 1: X=460, with the result that 500 is the multiple of 100 closest to X Y=360, with the result that 400 is the multiple of 100 closest to Y In this case, X+Y=820, so the multiple of 100 closest to X+Y is 800. Case 2: X=490, with the result that 500 is the multiple of ...”
April 7, 2019
GMATGuruNY posted a reply to One legacy of Madison Avenue's in the Sentence Correction forum
“Generally, a when-clause refers to an action performed at a particular moment: When Mary entered the room, John smiled. Here, the usage of when implies that the action in blue happened at a particular moment. An as-clause refers to an action performed over an extended period of time: Adam sang ...”
April 6, 2019
GMATGuruNY posted a reply to The 32 species that make up the dolphin family are closely r in the Sentence Correction forum
“There is no reason to repeat which in the OA. Even if more than one verb is attributed to COMMA + WHICH, the usage of one which should suffice.”
April 6, 2019
GMATGuruNY posted a reply to In a nationwide poll, N people were interviewed. If 1/4 in the Problem Solving forum
“Let N=12. Number who answered yes to question 1 = (1/4)12 = 3. Number who also answered yes to question 2 = (1/3)3 = 1. Number who didn''t answer yes to both questions = 12-1 = 11. This is our target. Now we plug N=12 into the answers to see which yields our target of 11. Only E works: ...”
April 6, 2019
April 6, 2019
GMATGuruNY posted a reply to Is x < 0? in the Data Sufficiency forum
“Statement 1: x³ < -1 The cube of x will be negative only if x itself is negative. Thus, x < 0. SUFFICIENT. Statement 2: x³ + x < -1 x(x² + 1) < -1 Since the square of a value cannot be negative, x² ≥ 0, with the result that the factor in blue must be POSITIVE. ...”
April 5, 2019
GMATGuruNY posted a reply to A pizza shop sold small pizzas for $4.5 in the Problem Solving forum
“The GMAT would list the answer choices in ascending or descending order, as follows: We can PLUG IN THE ANSWERS, which represent the number of small pizzas. The average cost per pizza = 5050/500 ≈ $10. Since the average cost ($10) is much closer to the price of a large pizza ($12.50) than ...”
April 5, 2019
GMATGuruNY posted a reply to Fossils of feathered dinosaurs - GMAT prep Exam pack 1 in the Sentence Correction forum
“A general truth is something that is true not just at a particular moment but is true IN GENERAL. Mary plays the saxophone. Here, the portion in blue expresses a general truth about Mary. To express a GENERAL TRUTH, we use the simple present tense. The SC above is intended to express a general ...”
April 2, 2019
GMATGuruNY posted a reply to While making a non-stop trip, a bus averaged m mph for the in the Data Sufficiency forum
“Distance traveled in the first 5 hours = 5m. Distance traveled in the remaining 4 hours = 4n. Average speed for the entire 9-hour trip = (5m + 4n)/9. To determine the average speed for the entire trip, we need to know the value of 5m+4n. Question stem, rephrased: What is the value of 5m+4n? ...”
April 2, 2019
GMATGuruNY posted a reply to OG13 - Q20 in the Sentence Correction forum
“The OA does not make a comparison. to double X = to increase X by 100% OA: Personal spending in the Julv-September quarter would more than double the...growth rate. Conveyed meaning: Personal spending in the July-September quarter would increase the growth rate by more than 100%.”
April 2, 2019
GMATGuruNY posted a reply to OG12, Q18 in the Sentence Correction forum
“OA: Plants are more efficient than fungi at acquiring carbon, in the form of carbon dioxide. Here, the modifier in green is an adverb in that it describes UNDER WHAT CIRCUMSTANCE the preceding blue action happens. Under what circumstance ARE plants MORE EFFICIENT at acquiring carbon? Under the ...”
April 2, 2019
GMATGuruNY posted a reply to Barry walks from one end to the other of a 30-meter long in the Problem Solving forum
“Let B = Barry''s rate and W = the walkway''s rate. The distance can be ANY VALUE. Let the distance = 240 meters. WITH the walkway, the time = 30 seconds: Here, Barry and the walkway WORK TOGETHER, so we ADD their rates: B+W = d/t = 240/30 = 8 meters per second. AGAINST the walkway, the ...”
April 1, 2019
GMATGuruNY posted a reply to 2+2+2^2+2^3+2^4+2^5+2^6+2^7+2^8=? in the Problem Solving forum
“2⁸ = 256 2⁷ = 128 Thus: 2⁸ + 2⁷ + 2⁶ + 2⁵ + 2⁴ + 2³ + 2² + 2 + 2 = 256 + 128 + (around 100) ≈ 500. Only A is viable: 2⁹ = 512. The correct answer is A.”
April 1, 2019
GMATGuruNY posted a reply to Cars emerging from a motorway arrive at a junction that in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of cars in the left lane. Answer choice C: 1700 If 700 cars per hour were diverted from the left lane to the right lane, the number of cars entering the right lane per hour would be twice as big as the number of cars entering the left lane ...”
March 30, 2019
GMATGuruNY posted a reply to A 3-character alpha-numeric code does have the following in the Problem Solving forum
“Number of options for the first character = 8. (Of the 10 digits, any digit but 0 or 9.) Number of options for the second character = 24. (Of the 26 letters in the alphabet, any but a or z.) Number of options for the third character = (number of options for the first character) + (number of ...”
March 29, 2019
GMATGuruNY posted a reply to The ratio of boys to girls in Class A is 3 to 4. The ratio in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of girls in Class A. Since b:g = 3:4, the number of girls must be a multiple of 4. Eliminate B, C and D. Answer choice A: g = 8. Since b:g = 3:4 = 6:8, b=6. Since Class A has one more boy and two more girls than Class B, in Class B, ...”
March 29, 2019
GMATGuruNY posted a reply to 100 students appeared for two tests-Maths and English. For in the Data Sufficiency forum
“100 = Only Math + Only English + Both + Neither For every student who passed in both the tests, 8 students passed only in Maths and 9 students passed only in English. Let B = both, implying that Only Math = 8B and that Only English = 9B. Thus: 100 = 8B + 9B + B + Neither 100 = 18B + Neither ...”
March 28, 2019
GMATGuruNY posted a reply to An optometrist charges $150 per pair for soft contact lenses in the Problem Solving forum
“Since $150 soft lenses and $85 hard lenses yield $1690 in revenue, we get: 150S + 85H = 1690 30S + 17H = 238 The sum on the left side must yield a units digit of 8. Since 17*4 = 68, it is likely that H=4: 30S + 17*4 = 338 30S + 68 = 238 30S = 170 S=9 S=9 and H=4 satisfy the condition ...”
March 28, 2019
GMATGuruNY posted a reply to OG-12 SC Q-43 Laos has a land area in the Sentence Correction forum
“D: Laos has a land area comparable to the size of Great Britain, but only four million in population, and many are members of hill tribes ensconced in the virtually inaccessible mountain valleys of the north. Error 1: The intent here is to compare the LAND AREA of Laos to the LAND AREA of Great ...”
March 28, 2019
GMATGuruNY posted a reply to Which of the following is the solution set for the inequalit in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the range of x. A: -1 < x < 0 Plugging x=-0.5 into the given inequality, we get: 0 < |-0.5| - 2(-0.5) < 3 0 < 0.5 + 1 < 3 0 < 1.5 > 3 Since x=-0.5 is a valid solution, the correct answer must include x=-0.5 within its ...”
March 28, 2019
GMATGuruNY posted a reply to A straight highway connects two cities P and Q, and goes via in the Data Sufficiency forum
“Statement 1: For every 2 hours spent at 30 mph and 1 hour spent at 50 mph, 3 hours are spent at 60 mph. Average speed per 6 hours = (2*30 + 1*50 + 3*60)/6 = 290/6. SUFFICIENT. Statement 2: Case 1: NQ = 180 miles, PM = 60 miles and MN = 50 miles Since NQ is traveled at 60 mph, the time for ...”
March 27, 2019
GMATGuruNY posted a reply to Geometry in the Problem Solving forum
“https://i.postimg.cc/N2Ky6DSp/square-divided-into-triangles.png Each triangle in the figure above is an isosceles right triangle with sides 1, 1 and √2. Shaded region = 4 triangles. Largest square = 16 triangles. Thus: (shaded region)/(largest square) = 4/16 = 1/4. The correct answer is ...”
March 27, 2019
GMATGuruNY posted a reply to A music festival took place over two days, Saturday and in the Data Sufficiency forum
“Anyone who attended the festival must have attended only Saturday, only Sunday, or both days. Let the total number of attendees = 100. Statement 1: 40% of attendees attended both days. No way to determine how many attendees attended only Saturday. INSUFFICIENT. Statement 2: 70% of attendees ...”
March 26, 2019
GMATGuruNY posted a reply to Boat World sells a certain boat and a certain trailer. What in the Data Sufficiency forum
“Let b = boat and t = trailer. What is the value of t? Statement 1: b = 7500+t No way to solve for t. INSUFFICIENT. Statement 2: b+t = 15000 No way to solve for t. INSUFFICIENT. Statements combined: Since we have two variables (b and t) and two distinct linear equations (b=7500+t and ...”
March 26, 2019
GMATGuruNY posted a reply to p, q, and r are different prime numbers. What is the value o in the Data Sufficiency forum
“Statement 1: (pq)² = 36 pq = 6 Case 1: p=2 and q=3 Case 2: p=3 and q=2 Since q can be different values, INSUFFICIENT. Statement 2: (qr)² = 225 qr = 15 Case 1: q=3 and r=5 Case 2: q=5 and r=3 Since q can be different values, INSUFFICIENT. Statements combined: Only one case ...”
March 26, 2019
GMATGuruNY posted a reply to √r + 2/√r = 4. What is the value of r + 4/r? in the Problem Solving forum
“(a+b)² = a² + b² + 2ab √r + 2/√r = 4 (√r + 2/√r)² = 4² (√r)² + (2/√r)² + 2(√r)(2/√r) = 16 r + 4/r + 4 = 16 r + 4/r = 12 The correct answer is A.”
March 26, 2019
GMATGuruNY posted a reply to How many trailing zeroes would be found in 63! upon in the Problem Solving forum
“TRAILING 0''s = the number of 0''s at the end of a large product. 63! = 63*62*61*....*3*2*1. Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of 63! will yield a 0 at the end of the integer representation of 63!. The prime-factorization of 63! includes FAR ...”
March 25, 2019
GMATGuruNY posted a reply to A certain NYC taxi driver has decided to start charging a in the Problem Solving forum
“Let r=100 cents. For 3 people, the cost per mile = 3*100 = 300 cents = 3 dollars. Let x = 2 miles. Regular cost for 3 people to travel 2 miles = 3*2 = 6 dollars. With a 50% discount, the cost in dollars = 3. This is our target. Now we plug x=2 and r=100 into the answers to see which ...”
March 25, 2019
GMATGuruNY posted a reply to 60% of all students in a class commute by public in the Problem Solving forum
“Use a DOUBLE-MATRIX to organize the data. Let P = public transportation, NP = not public transportation, S = science, NS = not science. 60% of all students in a class commute by public transportation. 30% of the students aspire to be scientists. The following matrix is yielded: ...”
March 25, 2019
GMATGuruNY posted a reply to GPREP SC-8 in the Sentence Correction forum
“Proposed revision: The sandpipers...are a result of residential and industrial development. This meaning is nonsensical. BIRDS cannot be a RESULT. This line of reasoning is valid: In D and E, the referent for in the northeastern United States is unclear.”
March 24, 2019
GMATGuruNY posted a reply to If P and Q are positive integers, and if P > 1, does P = in the Data Sufficiency forum
“Statement 1: Case 1: P=2 and Q=2, with the result that P divides evenly into Q In this case, P=Q, so the answer to the question stem is YES. Case 2: P=2 and Q=4, with the result that P divides evenly into Q In this case, P≠Q, so the answer to the question stem is NO. INSUFFICIENT. ...”
March 24, 2019
GMATGuruNY posted a reply to Is it true that x > 0? in the Data Sufficiency forum
“Statement 1: Case 1: x=0 In this case, the answer to the question stem is NO. Case 2: x≠0, allowing us to divide both sides by x x²/x = 2x/x x = 2 In this case, the answer to the question stem is YES. INSUFFICIENT. Statement 2: Case 1: x=0 In this case, the answer to the question ...”
March 24, 2019
GMATGuruNY posted a reply to Events A and B are independent and have equal probabilities in the Data Sufficiency forum
“Statement 1: P(at least one event occurs) = 1 - P(neither event occurs) Thus: P(at least A or B) = 1 - P(neither A nor B) Since P(at least A or B) = 0.84, we get: 0.84 = 1 - P(neither A nor B) P(neither A nor B) = 0.16 P(not A) * P(not B) = 0.16. Since it is given that P(A) = P(B), P(not ...”
March 23, 2019
GMATGuruNY posted a reply to In the given figure, if AS = 10 cm, SN = 5 cm and TN = 8 cm, in the Problem Solving forum
“Third-side rule: The third side a triangle must be LESS THAN THE SUM OF and GREATER THAN THE DIFFERENCE OF the other two sides. Here, all the sides must be INTEGER values. In triangle ANS, AS=10 and NS=5. Thus, third side AN must be an integer value less than 10+5 = 15 and greater than 10-5 = ...”
March 23, 2019
GMATGuruNY posted a reply to Express 2^20-2^19-2^18-2^17 as a power of 2. in the Problem Solving forum
“Test an analogous case with easier values: 2⁴ - 2³ - 2² - 2¹ = 16 - 8 - 4 - 2 = 2¹ The matching blue portions imply the following: 2²⁰ - 2¹⁹ - 2¹⁸ - 2¹⁷ = 2¹⁷ The correct answer is C.”
March 22, 2019
GMATGuruNY posted a reply to If (r+1/r)^2 = 5, what is the value of (r^3+1/r^3)^2? in the Problem Solving forum
“(r + 1/r)² = 5 r + 1/r = √5 (r + 1/r)² = 5 r² + 1/r² + 2(r)(1/r) = 5 r² + 1/r² + 2 = 5 r² + 1/r² = 3 Multiplying the blue equation and the red equation, we get: (r² + 1/r²)(r + 1/r) = 3√5 r³ + (r²)(1/r) + (1/r²)(r) + 1/r³ = 3√5 r³ + (r + 1/r) + 1/r³ = 3√5 ...”
March 21, 2019
GMATGuruNY posted a reply to A dessert recipe calls for 50% melted chocolate and 50% in the Problem Solving forum
“Chocolate percentage in the incorrect sauce: 40%. Chocolate percentage in the pure chocolate: 100%. Chocolate percentage in the mixture: 50%. Let I = the incorrect sauce and C = the pure chocolate. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. ...”
March 21, 2019
GMATGuruNY posted a reply to Skier Lindsey Vonn completes a straight 300-meter downhill in the Problem Solving forum
“Downhill speed - uphill speed = (x+10) - (x-8) = 18. Implication: The downhill speed is 18 mps greater than the uphill speed. We can PLUG IN THE ANSWERS, which represent the downhill speed. Since the downhill speed is 18 mps greater than the uphill speed, the correct answer must be GREATER ...”
March 21, 2019
GMATGuruNY posted a reply to Jeremiah invests his savings of $120,000 by dividing it in the Problem Solving forum
“On the GMAT, compounded interest is typically just a bit more than simple interest. Since the answer choices are all greater than 2% -- the percentage given in the prompt -- they must represent the HIGHER interest rate, with 2% representing the LOWER interest rate. Lower rate: Since 3/4 of ...”
March 21, 2019
GMATGuruNY posted a reply to If m and n are positive integers, is m+n divisible by 15? in the Data Sufficiency forum
“Rule: MULTIPLE OF X + MULTIPLE OF X = MULTIPLE OF X MULTIPLE OF X + NON-MULTIPLE OF X = NON-MULTIPLE OF X 225 = 9*25 Statements combined: Case 1: m=9 and n=25*15, with the result that m is a multiple of 9, n is a multiple of 15, and mn = 9*25*15 = 225*15 = multiple of 225 In this case, m+n ...”
March 21, 2019
GMATGuruNY posted a reply to What is the smallest positive integer n such that n / 420 ca in the Problem Solving forum
“A fraction will yield a terminating decimal if the prime-factorization of its denominator contains only 2''s and/or 5''s. n/420 = n/(2*2*3*5*7). For a terminating decimal to be yielded, the prime factors in red must CANCEL OUT with n, leaving only 2''s and 5''s in the denominator. Thus, the ...”
March 21, 2019
GMATGuruNY posted a reply to The consultant explained that companies in the Sentence Correction forum
“Generally, a one-word adverb such as tirelessly will not be positioned between a verb and its direct object. Incorrect: Companies lobby tirelessly government officials. Here, tirelessly (adverb) is awkwardly positioned between lobby (verb) and government officials (direct object). Correct: ...”
March 20, 2019
GMATGuruNY posted a reply to one another vs. others? in the Sentence Correction forum
“Some grammarians -- including me -- reserve each other for two elements and one another for more than two. Other grammarians consider the two modifiers interchangeable. A club has exactly three members: Ann, Beth, and Carol. The sentence above implies the following: Ann, Beth and Carol ...”
March 20, 2019
GMATGuruNY posted a reply to If arc PQR above is a semicircle, what is the length of diam in the Data Sufficiency forum
“An INSCRIBED ANGLE is formed by two chords. Thus, angle PQR is an inscribed angle. An inscribed angle that intercepts the diameter is a RIGHT ANGLE. Thus, angle PQR is a right angle, implying that triangle PQR is a RIGHT TRIANGLE. http://s15.postimage.org/xozmfjdh3/PQR.jpg In the figure ...”
March 20, 2019
GMATGuruNY posted a reply to Reiko drove from point A to point B at a constant speed, and in the Data Sufficiency forum
“Test the THRESHOLD. Since we want to know whether the speed from A to B is greater than 40mph, the threshold here is 40mph. Statement 1: Reiko''s average speed for the entire round trip, excluding the time spent at point B, was 80 miles per hour. Let the distance in each direction = 40 ...”
March 19, 2019
GMATGuruNY posted a reply to Danny spends $360 buying his favorite dolls. If he buy only in the Problem Solving forum
“Since a small doll costs $1 less than a large doll, the answer choices imply the following options for the price of a small doll: 4 5 6.2 7 8 Given that all of the values in the prompt are INTEGERS, the price of a small doll is almost certain to be a factor of 360. Only the values in blue ...”
March 18, 2019
GMATGuruNY posted a reply to Of the 25 cars sold at a car dealership, some had auto trans in the Data Sufficiency forum
“The following cases satisfy both statements: Case 1: 2 cars have neither 1 car has both antilock breaks and automatic transmission 22 cars have only automatic transmission. Case 2: 2 cars have neither 22 cars have both antilock breaks and automatic transmission 1 car has only automatic ...”
March 18, 2019
GMATGuruNY posted a reply to A box contains 3 red balls, 4 green balls, 5 yellow balls, 6 in the Problem Solving forum
“Determine the WORST-CASE-SCENARIO -- for each color of ball, the MAXIMUM number that can be removed WITHOUT removing 5 of the same color: 3 red 4 green 4 yellow 4 blue 4 white Sum = 3+4+4+4+4 = 19 Implication: It is possible to remove 19 balls without selecting 5 of the same color. ...”
March 18, 2019
GMATGuruNY posted a reply to To fill an order, a manufacturer had to produce 1000 tools in the Data Sufficiency forum
“Prompt: Total production = 1000n Statement 1: Total production for the first 5 days = 5*600 = 3000 Statement 2: Total production for the last 4 days = 4*1500 = 6000 Case 1: n=9, with no days between the first 5 days and the last 4 days Total production = 1000n = 1000*9 = 9000 Total ...”
March 17, 2019
GMATGuruNY posted a reply to What is the sum of all values of that satisfy the equation 4 in the Problem Solving forum
“For any quadratic in the form x² + bx + c = 0: Product of the roots = c Sum of the roots = -b Given equation: 4x² + 16 = 32x 4x² - 32x + 16 = 0 x² - 8x + 4 = 0 In the resulting quadratic, b=-8. Thus: Sum of the roots = -(-8) = 8. The correct answer is E.”
March 17, 2019
GMATGuruNY posted a reply to Set P {a, b, c, d, e, f, g} Set Q {a, b, c, d, e, f} in the Problem Solving forum
“One approach: Show that four of the five answers do NOT have to be true. P--> a=1, b=2, c=3, d=5, e=6, f=7, g=4 Range = 7-1 = 6, median = 4, mean = (1+2+3+5+6+7+4)/7 = 28/7 Q --> a=1, b=2, c=3, d=5, e=6, f=7 Range = 7-1 = 6, median = (3+5)/2 = 4, mean = (1+2+3+5+6+7)/6 = 24/6 = 4 ...”
March 17, 2019
GMATGuruNY posted a reply to If n is a positive integer and r is the remainder when in the Data Sufficiency forum
“What is the remainder when (n+1)(n-1) is divided by 8? Statement 1: Since n is odd, both n-1 and n+1 are EVEN, implying that (n-1)(n+1) = the product of two consecutive even integers. Given any two consecutive even integers, one will be a multiple of 4, while the other will be an even ...”
March 16, 2019
GMATGuruNY posted a reply to The sum of the weekly salaries of 5 employees is $3,250. If in the Problem Solving forum
“Since each salary increases by 10%, the sum increases by 10%. 10% of 3250 = 325. Average increase per employee = (total increase)/(number of employees) = 325/5 = 65. The correct answer is E.”
March 16, 2019
GMATGuruNY posted a reply to A rectangle has sides x and y and diagonal z. What is the pe in the Data Sufficiency forum
“Always look for special triangles such as 3-4-5 and 5-12-13. Statement 2: Case 1: https://i.postimg.cc/V0JX8Hqv/rectangle-with-x-y-and-z-1.png Case 2: https://i.postimg.cc/DWCWwPyX/rectangle-with-x-y-and-z-2.png Since each case will yield a different perimeter, INSUFFICIENT. Statement ...”
March 15, 2019
GMATGuruNY posted a reply to combinations in the Problem Solving forum
“The portion in red is incorrect: it should be not 4C1 but 2C1. If we select two upper case letters from two sets of twins, we must then select one lower case letter from the OTHER TWO SETS OF TWINS, yielding only two options for the lower case letter. For example: If we select A and B for the two ...”
March 15, 2019
GMATGuruNY posted a reply to If N is a positive two-digit integer, is N+1 prime? in the Data Sufficiency forum
“Good catch. In my solution, the lone exception (N=29) is now noted.”
March 14, 2019
GMATGuruNY posted a reply to If N is a positive two-digit integer, is N+1 prime? in the Data Sufficiency forum
“Statement 1: Any integer whose digits sum to a multiple of 3 must itself be a multiple of 3. Since N has a digit sum of 11, N+1 must have a digit sum of 12. One exception: If N=29, then N+1 = 30, which has a digit sum of 3. Since the digit sum of N+1 must be a multiple of 3 -- either 12 or 3 -- ...”
March 14, 2019
GMATGuruNY posted a reply to If √x+√y=7 and √x-√y=5, what is the value of xy? in the Problem Solving forum
“Adding the two equations, we get: 2√x = 12 √x = 6 x = 36 Substituting √x = 6 into √x+√y=7, we get: 6 + √y = 7 √y = 1 y = 1 Thus: xy = 36*1 = 36 The correct answer is C.”
March 14, 2019
GMATGuruNY posted a reply to If f(x)=ax^2+bx+c, where a, b and c are integers, is b=0? in the Data Sufficiency forum
“Statement 1: Since (49, 0) and (-49, 0) are both solutions, the quadratic must be as follows: f(x) = (x-49)(x+49) = x² - 49² In the resulting quadratic, b=0. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: If x-49 is a factor of the equation, then f(49) = 0. Case ...”
March 14, 2019
GMATGuruNY posted a reply to Ashley and Vinnie work on a sales staff with 8 other in the Problem Solving forum
“From the 10 people, 5 will be selected. Thus, P(Ashley is selected) = 5/10. From the 9 remaining people, 4 will be selected. Thus, P(Vinnie is selected) = 4/9. To combine these probabilities, we multiply: 5/10 * 4/9 = 2/9. The correct answer is C. Similar problem: ...”
March 14, 2019
GMATGuruNY posted a reply to A cosmetics company would like to market a six-item gift in the Problem Solving forum
“From 10 items, the number of ways to choose a bundle of 6 = 10C6 = (10*9*8*7*6*5)/(6*5*4*3*2*1) = 210. Subtracting the 49 bundles already eliminated from consideration, we get: 210-49 = 161. The correct answer is B.”
March 13, 2019
GMATGuruNY posted a reply to Set M is composed of the positive even integers up to 100. in the Problem Solving forum
“For any EVENLY SPACED SET: Count = (biggest - smallest)/(increment) + 1. Average = (biggest + smallest)/2. Sum = (count)(average). The INCREMENT is the difference between successive values. Even integers between 2 and 100, inclusive: Here, the integers are EVEN, so the increment = 2. Count ...”
March 13, 2019
GMATGuruNY posted a reply to A set of 51 different integers has a median of 30 and a in the Problem Solving forum
“Range = biggest - smallest Smallest = biggest - range Since the range = 60, we get: Smallest = biggest - 60 To minimize the smallest integer, we must minimize the biggest integer. Since the median of the 51 distinct integers = 30, there must be 25 integers above 30, with the other 25 ...”
March 13, 2019
GMATGuruNY posted a reply to What is the sum of the integers from 1 to 999, inclusive? A in the Problem Solving forum
“For any set of consecutive integers: Count = biggest - smallest + 1. Average = (biggest + smallest)/2. Sum = (count)(average). In the set above: Count = 999 - 1 + 1 = 999. Average = (999 + 1)/2 = 500. Sum = (999)(500) = (1000-1)(500) = 500000-500 = 499500. The correct answer is B.”
March 13, 2019
GMATGuruNY posted a reply to Peter and Tom shared the driving on a certain trip. If Peter in the Problem Solving forum
“Let the time for each driver = 1 hour. Let the total distance = 5 miles, implying that Peter''s distance = (2/5)(5) = 2 miles and that Tom''s distance = 5-2 = 3 miles. Since Peter drives 2 miles in 1 hour, Peter''s rate = 2 mph. Since Tom drives 3 miles in 1 hour, Tom''s rate = 3 mph. Thus: ...”
March 13, 2019
GMATGuruNY posted a reply to Which of the following could be the number of diagonals of a in the Problem Solving forum
“To form a diagonal, we must choose 2 vertices. But any pair of vertices that forms a side of the polygon cannot serve to form a diagonal. Thus: Number of diagonals = (number of ways to choose 2 vertices) - (number of sides of the polygon) When the prompt includes the phrase which of the ...”
March 12, 2019
GMATGuruNY posted a reply to Alice, Bob, Cindy, Darren, Eddie, Fabian sit on six chairs a in the Problem Solving forum
“To count circular arrangements: 1. Place someone in the circle 2. Count the number of ways to arrange the REMAINING people Once Alice has been placed in the circle: Number of options for Bob = 1. (Must be in the seat opposite Alice) Number of options for Cindy = 4. (Any of the 4 remaining ...”
March 12, 2019
GMATGuruNY posted a reply to If x and y are positive integers, x/y=? in the Data Sufficiency forum
“Statement 1: Case 1: x=2 and y=1, with the result that 2^(x+y) * 3^(xy) = 2³3² = 72 In this case, x/y = 2/1 = 2. Case 2: x=1 and y=2, with the result that 2^(x+y) * 3^(xy) = 2³3² = 72 In this case, x/y = 1/2 = 1/2. Since x/y can be different values, INSUFFICIENT. Statement 2: Here, x=2 ...”
March 12, 2019
GMATGuruNY posted a reply to Roman City in the Critical Reasoning forum
“E: mosaic designs with which artisans who lived in various parts of the Roman Empire were familiar. Here, the two blue portions constitute an adjective serving to modify designs. Question: What KIND of designs? Answer: Designs WITH WHICH ARTISANS WERE FAMILIAR. Put another way: Artisans were ...”
March 11, 2019
GMATGuruNY posted a reply to Carmen currently works 30 hours per week at her part-time jo in the Data Sufficiency forum
“Rate and time have a RECIPROCAL relationship. If the hourly rate DOUBLES, then the same income will be yielded in 1/2 the total time. Statement 1: Actual hourly rate = 225/30 = $7.50, implying that an additional $1.50 per hour will increase the hourly rate to $9. (increased hourly ...”
March 11, 2019
GMATGuruNY posted a reply to schistosomiasis and malaria. in the Critical Reasoning forum
“M --> more than 50% of all disease cases over the past 5 years S --> 40% of all disease cases 5 years ago, 30% of all disease cases now For each answer choice: Try to devise a case that aligns with the information in the passage but CONTRADICTS the answer choice, thus proving that the ...”
March 9, 2019
GMATGuruNY posted a reply to Verbal Review 18 : Kudzu, an Asian vine in the Sentence Correction forum
“Generally, COMMA + SINCE after a clause serves to express a CAUSAL relationship. An OA in GMATPrep: Prospecting for gold was a relatively easy task, since erosion put gold literally within reach of anybody with a pan. Here, the clause in blue serves to express what CAUSED prospecting to be a ...”
March 9, 2019
GMATGuruNY posted a reply to If p is a positive integer, is 2p + 1 prime? in the Data Sufficiency forum
“Statements combined: Case 1: p=11 --> p is prime, but its units digits is not prime In this case, 2p+1 = 2*11 + 1 = 23. Since 23 is prime, the answer to the question stem is YES. Case 2: p=19 --> p is prime, but its units digit is not prime In this case, 2p+1 = 2*19 + 1 = 39. Since 39 ...”
March 9, 2019
GMATGuruNY posted a reply to If a certain reel of film runs at 5/6 of a frame per second, in the Problem Solving forum
“2580 frames * (1 second)/(5/6 frame per second) * (1 minute)/(60 seconds) = 2580/50 = a little over 50 minutes. The correct answer is B.”
March 9, 2019
GMATGuruNY posted a reply to When positive integer x is divided by positive interger y, in the Problem Solving forum
“When one positive integer is divided by another, we typically represent what is left over as a REMAINDER or as a DECIMAL. There is a relationship between the two representations: Remainder/Divisor = Decimal. When 5 is divided by 2: Remainder representation: 5/2 = 2 R1 Decimal ...”
March 8, 2019
GMATGuruNY posted a reply to The R students in a class agree to contribute equally to buy in the Problem Solving forum
“Let y=$10 and R=10 students, with the result that the original share per student = ($10)/(10 students) = $1. Let x=9, implying that the number of students decreases by 9 to 1. New share per student = ($10)/(1 student) = $10. Increase in share per student = 10-1 = $9. The correct answer must ...”
March 8, 2019
GMATGuruNY posted a reply to Is the average (arithmetic mean) of x, y, and z equal to the in the Data Sufficiency forum
“Statement 1: In other words, y is HALFWAY BETWEEN x and z, implying that x, y and z are EVENLY SPACED. For any evenly spaced set, the average = the median. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: x+z = 2y (x+z)/2 = y Implication: y is the average of x and z ...”
March 7, 2019
GMATGuruNY posted a reply to What is the remainder when -12 is divided by -5? in the Problem Solving forum
“This problem is not relevant to the GMAT. On the GMAT, problems involving remainders are constrained to POSITIVE INTEGERS. From the Math Review in the OG: If x and y are positive integers, there exist unique integers q and r, called the quotient and remainder, respectively, such that y = xq + r ...”
March 7, 2019
GMATGuruNY posted a reply to A triangle of area 30 is formed by the line x/c + y/(c+7) - in the Problem Solving forum
“Given that the area and the answer choices are all integers, the triangle is probably a Pythagorean Triple. The only Pythagorean Triple with an area of 30 is 5-12-13. In the given equation, test c=5, with the result that c+7 = 12: x/5 + y/12 - 1 = 0 If x=0, then y=12, implying a y-intercept ...”
March 5, 2019
GMATGuruNY posted a reply to Joey works at a clothing store and receives an employee in the Problem Solving forum
“Since the discount = 10% = 1/10, and the resulting discount price is an integer value, the regular price must be a dollar value that is a multiple of 10. The correct answer is E.”
March 5, 2019
GMATGuruNY posted a reply to When 32 is divided by k, the remainder is k-3. What is the in the Data Sufficiency forum
“Dividing 32 by k leaves a remainder of k-3. In other words, 32 is equal to k-3 more than a multiple of k: 32 = ak + (k-3), where a is a nonnegative integer and k is an integer such that k≥3. Simplifying 32 = ak + (k-3), we get: 35 = ak + k 35 = k(a+1) The resulting equation implies that ...”
March 5, 2019
GMATGuruNY posted a reply to If x and y are positive integers and (x-y)^2+y^2=25, which o in the Problem Solving forum
“Identify two perfect squares that sum to 25: 1, 4, 9, 16... The two values in blue sum to 25. If y=3 and x=7, then (x-y)² = (7-3)² = 16 and y² = 9, with the result that (x-y)² + y² = 25. The correct answer is B.”
March 5, 2019
GMATGuruNY posted a reply to OG Before 1988, insurance companies in California in the Sentence Correction forum
“Generally, COMMA + VERBing serves to modify the nearest preceding action and the agent of this action. Given this rule, I received a PM requesting that I justify the usage of COMMA + needing in the OA: Insurance companies in California were free to charge whatever rates the market would bear, ...”
March 3, 2019
GMATGuruNY posted a reply to In a certain school, there are 160 boys and 240 girls. If 15 in the Problem Solving forum
“Left-handed boys = 15% of 160 = 24. Left-handed girls = 25% of 240 = 60. (total left-handed)/(total students) = (24+60)/(160+240) = 84/400 = 21/100 = 21%. The correct answer is C.”
March 2, 2019
GMATGuruNY posted a reply to If \(2^{4x}=3,600\), what is the value of \((2^{(1-x)})^2\)? in the Problem Solving forum
“\((2^{(1-x)})^2\) = \(2^{2-2x}\) = \(2^2/2^{2x}\) = \(4/2^{2x}\) We need to know the value of \(2^{2x}\): \(2^{4x}=3,600\) \((2^{2x})^2=3,600\) \(2^{2x}= 60\) Substituting \(2^{2x}= 60\) into \(4/2^{2x}\), we get: 4/60 = 1/15 The correct answer is B.”
March 2, 2019
GMATGuruNY posted a reply to Car B starts at point X and moves clockwise around a circula in the Problem Solving forum
“π ≈ 3. Car B is traveling for more than 10 hours, so answer choices D and E are too small, and A is unlikely. The correct answer is either B or C. Circumference of track = 20π ≈ 60 miles. In 10 hours, distance for B = 2*10 = 20 miles. 60-20 = 40 miles between A and B. A and B now ...”
March 2, 2019
GMATGuruNY posted a reply to Which of following satisfies the inequality (2x-49)(x^2+6x+1 in the Problem Solving forum
“The two factors must have DIFFERENT SIGNS. Each of the answer choices will yield a positive value for x² + 6x + 10. Thus, the correct answer must yield a negative value for 2x-49. Only A is viable: (2*24) - 49 = -1. The correct answer is A.”
March 1, 2019
GMATGuruNY posted a reply to Andrew bought pizzas for his swim team. Pepperoni pizzas in the Problem Solving forum
“Posted and answered about a week ago: https://www.beatthegmat.com/andrew-bought-pizzas-for-his-swim-team-pepperoni-pizzas-cos-t306615.html#827261”
March 1, 2019
GMATGuruNY posted a reply to The three squares above share vertex A with AF = FE and AE = in the Problem Solving forum
“Let AF=FE=1, with the result that AE=ED=2: https://i.postimg.cc/2qmj2KbL/probability-and-three-squares.png As the figure illustrates: shaded region = 1+1+1 = 3 ABCD = 4*4 = 16 shaded/ABCD = 3/16 The correct answer is D.”
March 1, 2019
GMATGuruNY posted a reply to Working simultaneously and independently at an identical con in the Problem Solving forum
“Use the following equation: (machines)(time) / output = (machines)(time) / output In the equation above: Machines and time are INVERSELY PROPORTIONAL. As the number of machines increases, the amount of time required to produce the same output decreases. Machines and output are DIRECTLY ...”
February 28, 2019
GMATGuruNY posted a reply to The restorative power of sleep is graphically approximated b in the Problem Solving forum
“Multiplying the equation by -1, we get: y = x² - 16x - 36 y = (x-18)(x+2) The restorative power -- the value of y -- is equal to 0 when x=18 or x=-2. Since the time cannot be a negative value, only x = 18 hours is viable. The correct answer is E.”
February 28, 2019
GMATGuruNY posted a reply to In June 1989, what was the ratio of the number of sales tran in the Data Sufficiency forum
“What is (June X)/(June Y)? Statement 1: In June 1989, Salesperson X made 50 percent more sales transactions than Salesperson Y did in May 1989. (June X)/(May Y) = 150/100 = 3/2. INSUFFICIENT. Statement 2: In June 1989, Salesperson Y made 25 percent more sales transactions than in May ...”
February 28, 2019
GMATGuruNY posted a reply to How many whole numbers between 100 and 400, inclusive, conta in the Problem Solving forum
“(integers with the digit 2) = (all integers between 100 and 399, inclusive) - (integers without the digit 2) All integers between 100 and 399, inclusive: For any set of consecutive integers, count = biggest - smallest + 1. In this case: count = 399-100+1 = 300 Integers without the digit 2: ...”
February 27, 2019
GMATGuruNY posted a reply to A square playground has the same area as a rectangular in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent a side of the square. Since the dimension of the rectangular playground are INTEGER values, the correct answer is probably also an integer. When the correct answer is plugged in, the square and the rectangle will have the same area. D: 50, implying ...”
February 27, 2019
GMATGuruNY posted a reply to Two hoses are pouring water into an empty pool. Hose 1 alone in the Problem Solving forum
“Let the pool = 12 gallons. Since Hose 1 takes 6 hours to fill the 12-gallon pool, the rate for Hose 1 = w/t = 12/6 = 2 gallons per hour. Since Hose 2 takes 4 hours to fill the 12-gallon pool, the rate for Hose 2 = w/t = 12/4 = 3 gallons per hour. Since the combined rate for the two hoses = 2+3 = ...”
February 27, 2019
GMATGuruNY posted a reply to What is the value of a+b? in the Data Sufficiency forum
“Statements combined: Adding the two equations, we get: a² + b²+ 2ab - 2a - 2b = 63 (a+b)² - 2(a+b) = 63 (a+b)(a+b-2) = 63 Let x = a+b. Substituting x=a+b into (a+b)(a+b-2) = 63, we get: (x)(x-2) = 63 x² - 2x - 63 = 0 (x-9)(x+7) = 0 x=9 or x=-7 Since x=a+b, it is possible that ...”
February 26, 2019
GMATGuruNY posted a reply to On a Saturday night, each of the rooms at a certain motel in the Problem Solving forum
“If 10 rooms are rented for $40 instead of $60 -- a decrease of $20 per room -- the total decrease = 10*20 = $200. Since the value in blue constitutes a 25% reduction in the total rent, it must be equal to 1/4 of the total rent: 200 = (1/4)R 800 = R. The correct answer is B.”
February 26, 2019
GMATGuruNY posted a reply to A manufacturer makes umbrellas at the cost of c dollars per in the Problem Solving forum
“How many umbrellas can it afford to sell at the below-cost rate of b dollars per umbrella and still make a 100% profit? If c=1 and r=2 -- implying that the cost per umbrella = $1 and that the retail price per umbrella = $2 -- then 100% profit will be yielded only if ALL of the umbrellas are sold at ...”
February 26, 2019
GMATGuruNY posted a reply to On rainy mornings, mo drinks exactly N cups of hot chocolate in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of rainy days. When the correct answer is plugged in, the total number of cups = 26. B: 3 rainy days, implying 4 non-rainy days Since 5 cups of tea are consumed are on each of the 4 non-rainy days, the total number of tea cups = 5*4 = 20. ...”
February 26, 2019
GMATGuruNY posted a reply to It takes Carlos 9 minutes to drive from home to work at an in the Problem Solving forum
“(new rate)/(old rate) = (6 miles per hour)/(22 miles per hour) = 6/22 = 3/11. Rate and time have a RECIPROCAL relationship. Since the new rate is 3/11 of the old rate, the new time must be 11/3 of the old time: (11/3)(9 minutes) = 33 minutes. The correct answer is B.”
February 26, 2019
GMATGuruNY posted a reply to A is the set of 6-digit positive integers whose first three in the Problem Solving forum
“The GMAT is unlikely to test divisibility by 7. An integer of the form XYZXYZ must be divisible by 7, but this issue seems irrelevant to the GMAT. For this reason, I''ve replaced answer choice A with the value in red: To determine whether an integer is divisible by 11: 1. From the left to ...”
February 26, 2019
GMATGuruNY posted a reply to What is the difference between the areas of the squares ABCD in the Data Sufficiency forum
“Statement 1: Case 1: DC=10 and EC=6, with the result that CDE = (1/2)(10)(6) = 30 In this case, ABCD-EFGC = 10² - 6² = 100 - 36 = 64. Case 2: DE=20 and EC=3, with the result that CDE = (1/2)(20)(3) = 30 In this case, ABCD-EFGC = 20² - 3² = 400 - 9 = 391. Since ABCD-EFGC can be different ...”
February 25, 2019
GMATGuruNY posted a reply to How many positive two-digit numbers are odd, not divisible b in the Problem Solving forum
“For any set of consecutive integers: count = biggest - smallest + 1 Thus: Number of two-digit integers between 10 and 99, inclusive = 99-10+1 = 90. Of these 90 consecutive integers, 1 of every 3 will be a multiple of 3, implying that 2/3 will NOT be divisible by 3: (2/3)(90) = 60. Of these ...”
February 25, 2019
GMATGuruNY posted a reply to 2016 OG CR 30 in the Critical Reasoning forum
“Why do people who do regular volunteer work live longer? The argument concludes that ENDORPHINS are the cause. One way to weaken this conclusion is to suggest an ALTERNATE CAUSE. D: People tend not to become involved in regular volunteer work unless they are healthy and energetic to begin with. ...”
February 25, 2019
GMATGuruNY posted a reply to Vivian drives to her sister’s house and back. She takes th in the Problem Solving forum
“When the SAME DISTANCE is traveled at two different speed, the average speed for the entire trip will be just a little less than the average of the two speeds. The reason: The trip at the lower speed takes longer than the trip at the higher speed. Since more time is spent at the lower speed, the ...”
February 25, 2019
GMATGuruNY posted a reply to Before January, the price of a dress was D and the price of in the Problem Solving forum
“Let H=100 and D=500. D increased by 40% = 500 + (40/100)(500) = 500+200 = 700. H increased by 50% = 100 + (50/100)(100) = 100+50 = 150. New sum = 700+150 = 850. Amount paid = new sum discounted by 30% = 850 - (30/100)(850) = 850-255 = 595. The question stem asks for the amount paid. The ...”
February 25, 2019
GMATGuruNY posted a reply to All assets in Karina's investment portfolio are divided betw in the Problem Solving forum
“To MINIMIZE the percent for the largest balance, MAXIMIZE the percents for the 3 smallest balances. We can PLUG IN THE ANSWERS, which represent the percent in the largest balance. When the correct answer is plugged in, the 4 percents will sum to 100%. Since the question stem asks for the smallest ...”
February 25, 2019
GMATGuruNY posted a reply to In a certain class, the ratio of girls to boys is 5:4. How m in the Data Sufficiency forum
“g:b = 5:4 = 10:8 = 15:12 = 20:16 = 25:20... Statement 1: In other words, 4 boys are equal to 20% of the current number of boys, implying the blue ratio above, since 20% of 20 boys = 4 boys. In the blue ratio above, the number of girls = 25. SUFFICIENT. Statement 2: Test the smaller red ...”
February 24, 2019
GMATGuruNY posted a reply to The total of company C's assets in 1994 was 300% greater in the Problem Solving forum
“Let N dollars in 1992 = 1. Since the assets in 1993 are 300% greater than the N dollars in 1992, the assets in 1993 = 1 + (300% of 1) = 1+3 = 4. Since the assets in 1994 are 400% greater than the assets in 1993, the assets in 1994 = 4 + (400% of 4) = 4 + 16 = 20. The question stem asks for ...”
February 23, 2019
GMATGuruNY posted a reply to Andrew bought pizzas for his swim team. Pepperoni pizzas cos in the Problem Solving forum
“13x + 17y = 184. Multiples of 13: 13, 26, 39, 52, 65, 78, 91, 104... Multiple of 17: 17, 34, 51, 68, 85, 102, 119.... The values in blue sum to 184. Since 65/13 = 5 and 119/17 = 7, the number of pizzas = 5+7 = 12. The correct answer is A.”
February 23, 2019
GMATGuruNY posted a reply to Nathan took out a student loan for 1200$ at 10 percent in the Problem Solving forum
“Since the 10% rate is compounded annually, the amount of interest increases by 10% each year: First-year interest = 10% of 1200 = 120. Second-year interest = (first-year interest) + 10% = 120 + 12 = 132. Third-year interest = (second-year interest) + 10% = 132 + 13.2 = 145.2. Total interest = ...”
February 22, 2019
GMATGuruNY posted a reply to Ten theater students are to begin work on a set for a in the Problem Solving forum
“(50 days)/(60 days) = 5/6. To finish the job in 5/6 of the normal time, the crew requires 6/5 of the normal number of students -- an increase of 1/5: (1/5)(10) = 2 more students. The correct answer is A.”
February 22, 2019
GMATGuruNY posted a reply to In how many ways a cricket team consisting of 5 batsmen, 4 in the Problem Solving forum
“From 7 batsmen, the number of ways to choose 5 = 7C5 = (7*6*5*4*3)/(5*4*3*2*1) = 21. From 6 bowlers, the number of ways to choose 4 = 6C4 = (6*5*4*3)/(4*3*2*1) = 15. From 3 wicketkeepers, the number of ways to choose 1 = 3. From 3 allrounders, the number of ways to choose 1 = 3. To combine these ...”
February 22, 2019
GMATGuruNY posted a reply to How many different arrangements are possible to place seven in the Problem Solving forum
“Let the 3 math books = A, B, C and the remaining 4 books = D, E, F, G. Since the 3 math books must be next to one another, put them together in a block: E.”
February 22, 2019
GMATGuruNY posted a reply to If 1/x-1/y=1/z, what is the value of y, in terms of x and z? in the Problem Solving forum
“Let x=1 and y=3/2, with the result that 1/z = 1 - 2/3 = 1/3, so z=3. Since the question stem asks for the value of y, the correct answer must yield 3/2 when x=1 and z=3. Since B and D include x-z and thus will yield a negative result, eliminate B and D. Since E includes only multiplication and ...”
February 22, 2019
GMATGuruNY posted a reply to Is p^3 < p? in the Data Sufficiency forum
“Statements combined: Case 1: p=0, with the result that p is an integer less than 1 In this case, p³=p, so the answer to the question stem is NO. Case 2: p=-2, with the result that p is an integer less than 1 In this case, p³ < p, so the answer to the question stem is YES. Since the answer ...”
February 22, 2019
GMATGuruNY posted a reply to In the figure shown, AB = AC = 12. Which of the following is in the Problem Solving forum
“https://i.postimg.cc/06HLPxqC/circle-in-a-sector.png AOP passes through the center of the inscribed circle and thus must BISECT sector ACB. AB, AP and AC are all radii of sector ACB and thus are equal. The prompt indicates AB=AC=12. Thus: AP=12. As shown in the figure, AOM is a 30-60-90 ...”
February 22, 2019
GMATGuruNY posted a reply to The sum of two integers is 27. The larger integer is 25% in the Problem Solving forum
“25% greater = 1/4 greater. If the smaller integer = 4, then the larger integer = 4 + (1/4)4 = 5. The values in red imply that the two integers summing to 27 must be in a RATIO OF 4 TO 5: 4, 5 8, 10 12, 15 The case in blue sums to 27, with the result that larger-smaller = 15-12 = 3. The ...”
February 21, 2019
GMATGuruNY posted a reply to In the figure above, the angle marked at c has been created in the Data Sufficiency forum
“Since b and c form a straight line, b+c = 180. Thus, the calculate a+b+c, we need to know the value of a. Question stem, rephrased: What is the value of a? Statement 1: SUFFICIENT. Statement 2: No information about a. INSUFFICIENT. The correct answer is A.”
February 21, 2019
GMATGuruNY posted a reply to At a certain committee meeting only associate professors and in the Problem Solving forum
“Total number of items brought to the meeting = 21. (10 charts and 11 pencils) Number of items brought by each person = 3. (Either 2 pencils and 1 chart or 1 pencil and 2 charts) Thus: Number of people = (total number of items)/(number of items per person) = 21/3 = 7. The correct answer is B.”
February 21, 2019
GMATGuruNY posted a reply to Four cards are chosen from a standard deck: two aces (one of in the Problem Solving forum
“The following cases are possible: (-1)(1) = -1 (-1)(-2) = 2 (-1)(2) = -2 (1)(-2) = -2 (1)(2) = 2 (-2)(2) = -4 Of the 6 cases above, the 4 in blue each yield a product that is negative, odd or both: 4/6 = 2/3 ≈ 67%. The correct answer is D.”
February 20, 2019
GMATGuruNY posted a reply to A box contains 1 red ball, 3 green balls, 5 yellow balls, 7 in the Problem Solving forum
“Determine the WORST-CASE-SCENARIO -- for each color of ball, the MAXIMUM number that can be removed WITHOUT removing 7 of the same color: 1 red 3 green 5 yellow 6 blue 6 white 6 black Sum = 1+3+5+6+6+6 = 27. Implication: It is possible to remove 27 balls without selecting 7 of the same ...”
February 19, 2019
GMATGuruNY posted a reply to If M, N are integers greater than 1 such that 2M<N, which in the Problem Solving forum
“54, 52 and 50 are options for TWICE the sum. Thus, I, II, and III imply the following options for the ACTUAL SUM: I: 27 II: 26 III: 25 Case 1: M=2 Since it is required that N>2M, N≥5 M=2 and N=5 --> sum = 2+3+4+5 = 14 M=2 and N=6 --> sum increases by 6 --> 14+6 = 20 M=2 and ...”
February 19, 2019
GMATGuruNY posted a reply to If A and B are two fixed constants such that the system in the Problem Solving forum
“The system will have an infinite number of solutions for (x, y) if the two equations are THE SAME: 2(x+y) - A = 0 --> 2x + 2y - A = 0 --> 6x + 6y - 3A = 0 3x + By - 6 = 0 -----------------------> 6x +2By - 12 = 0 The equations in blue will be the same if 3A=12 and 2B=6, with the result ...”
February 18, 2019
GMATGuruNY posted a reply to Is m > n? in the Data Sufficiency forum
“Both statements are satisfied if n=1 and m=2 or if n=1 and m=-2. Since m > n in the first case but m < n in the second case, the two statements combined are INSUFFICIENT. The correct answer is E.”
February 18, 2019
GMATGuruNY posted a reply to If the original price of an item in a retail store is marked in the Data Sufficiency forum
“Let the original price = 100. Then the markup = (m/100)*100 = m. The resulting price = 100+m. The subsequent discount = d/100*(100+m) = d + md/100 Thus, the total percent change = percent increase - percent decrease = m - d - md/100. For the final price to be greater than the original price, ...”
February 17, 2019
GMATGuruNY posted a reply to In triangle ABC, point X is the midpoint of side AC and poin in the Data Sufficiency forum
“http://s7.postimage.org/6u5drpql3/triangle_RCS_1.jpg Triangles RCS and ABC: Side RC = 1/4(AC). Side SC = 1/4(BC). The two triangles share angle BCA. Triangles with a shared angle (BCA) formed by corresponding sides in the same proportion (RC:AC = 1:4, SC:BC = 1:4) are SIMILAR. Thus, ...”
February 17, 2019
GMATGuruNY posted a reply to A and B start from Opladen and Cologne respectively at the in the Problem Solving forum
“When two elements travel at different speeds, their TIME RATIO to travel the same distance will always be the same. If A takes 1/2 as long as B to travel 10 miles, then A will take 1/2 as long as B to travel 1000 miles. If A takes 3 times as long as B to travel 500 miles, then A will take three ...”
February 17, 2019
GMATGuruNY posted a reply to Flor is choosing three of five colors of paint to use for in the Problem Solving forum
“Let the 5 colors be GYABC. From the 5 colors, the number of ways to choose 3 = 5C3 = (5*4*3)/(3*2*1) = 10. Of these 10 combinations, 3 are not allowed: GYA GYB GYC Subtracting these 3 bad combinations, we get: 10-3 = 7. The correct answer is A.”
February 17, 2019
GMATGuruNY posted a reply to If a = 15! + 13, which of the following are factors of a? I in the Problem Solving forum
“MULTIPLE OF X + MULTIPLE OF X = MULTIPLE OF X. MULTIPLE OF X + NON-MULTIPLE OF X = NON-MULTIPLE OF X. Since the prime-factorization of 15! includes 13, we get: a = 15! + 13 = multiple of 13 + multiple of 13 = multiple of 13. Since a is a multiple of 13, option I is a factor of a. Eliminate ...”
February 16, 2019
GMATGuruNY posted a reply to If a coin has an equal probability of landing heads up or ta in the Problem Solving forum
“P(H) = 1/2. P(T) = 1/2. One way to get exactly 1 heads in 3 flips: P(HTT) = 1/2 * 1/2 * 1/2 = 1/8. Since H can appear in a total of 3 positions -- 1st flip, 2nd flip, or 3rd flip -- we multiply by 3: 1/8 * 3 = 3/8 = 0.375. The correct answer is C.”
February 16, 2019
GMATGuruNY posted a reply to A magician has five animals in his magic hat: 3 doves and 2 in the Problem Solving forum
“AND means MULTIPLY. OR means ADD. Case 1: 2 doves P(1st animal is a dove) = 3/5. (Of the 5 animals, 3 are doves.) P(2nd animal is a dove) = 2/4. (Of the 4 remaining animals, 2 are doves.) Since in Case 1 we need the 1st animal to be a dove AND the 2nd animal to be a dove, we MULTIPLY the ...”
February 16, 2019
GMATGuruNY posted a reply to What is the value of (2^{2020} + 2^{2018}) / (2^{2020}-2^{20 in the Problem Solving forum
“(2²⁰²⁰ + 2²⁰¹⁸)/(2²⁰²⁰ - 2²⁰¹⁸) = (2²⁰¹⁸)(2² + 1) / (2²⁰¹⁸)(2² - 1) = 5/3. The correct answer is B.”
February 15, 2019
GMATGuruNY posted a reply to If Rebeca drives to work at x mph she will be one minute lat in the Data Sufficiency forum
“In deference to your mother, the offensive second "c" has been removed from my solution.”
February 15, 2019
GMATGuruNY posted a reply to A certain military vehicle can run on pure Fuel X, pure Fuel in the Data Sufficiency forum
“Statement 1: X = 20 miles per gallon. Y = 40 miles per gallon. Since the mixture of X and Y in the tank allows 200 miles to be covered using 8 gallons, we get: X+Y = 200/8 = 25 miles per gallon. To determine how X and Y must be combined to yield a rate of 25 miles per gallon, use ALLIGATION. ...”
February 15, 2019
GMATGuruNY posted a reply to If Rebeca drives to work at x mph she will be one minute lat in the Data Sufficiency forum
“To make the math easier, we can replace the given values with rounder numbers, as follows: Since Rebeca arrives 1 hour late when traveling at the lower speed and 1 hour early when traveling at the higher speed, the time at the lower speed must be 2 hours greater than the time at the higher ...”
February 15, 2019
GMATGuruNY posted a reply to Which of the following numbers is closest to 100*(11-sqrt( in the Problem Solving forum
“100(11 - √119)(11 + √119) = 100(11² - √119²) = 100(121-119) = 100*2 = 200. When the correct answer is multiplied by 11+√119, the result must be as close as possible to 200. 11+√119 = 11 + (a bit less than 11) = a bit less than 22. Since 9*22 = 198, multiplying 9.2 by a bit less than ...”
February 14, 2019
GMATGuruNY posted a reply to What is the value of a^3+b^3 ? in the Data Sufficiency forum
“Statement 1: Case 1: a=0 and b=1, with the result that a+b = 0+1 = 1 In this case, a³+b³ = 0³ + 1³ = 1 Case 2: a=2 and b=-1, with the result that a+b = 2-1 = 1 In this case, a³+b³ = 2³ + (-1)³ = 7 Since a³+b³ can be different values, INSUFFICIENT. Statement 2: Case 3: a=1 and b=1, ...”
February 14, 2019
GMATGuruNY posted a reply to A group of x people is practicing levitation yoga. One-fourt in the Problem Solving forum
“Let x=12. Since 1/4 of the people rise up, the number who rise up = (1/4)(12) = 3. Since 3 people come back down, EVERYONE who rises up comes back down, with the result that all 12 people are practicing yoga on the ground. How many people are now practicing yoga on the ground? The correct ...”
February 14, 2019
GMATGuruNY posted a reply to How many prime factors does the number X have? 1) X is divi in the Data Sufficiency forum
“Statement combined: Case 1: X = 53*2 = 106, with the result that X is divisible by 1, 2, 53, and 106 In this case, X has TWO prime factors: 2 and 53 Case 2: X = 53³, with the result that X is divisible by 1, 53, 53², and 53³ In this case, X has only ONE prime factor: 53 Since the number of ...”
February 13, 2019
GMATGuruNY posted a reply to A terminating decimal is a number with a finite number of in the Data Sufficiency forum
“A fraction will yield a terminating decimal if -- when the fraction is fully reduced -- the prime-factorization of its denominator includes only 2''s and or 5''s. Statement 1: Let x = an odd multiple of 5. Since the next largest odd multiples of 5 will be x+10 and x+20, we get: p = x + (x+10) ...”
February 12, 2019
GMATGuruNY posted a reply to If O is the center of the circle with diameter AB and T is a in the Problem Solving forum
“A radius drawn to a tangent point yields a RIGHT ANGLE: https://i.postimg.cc/Wq6BDNH7/two-triangles-and-semicircle-1.png In the figure above: Radius OT forms a right angle at tangent point T. OA and OT are radii and thus are equal. Since OA=OT, opposite angles OAT and ATO are equal. We can ...”
February 12, 2019
GMATGuruNY posted a reply to A positive 5-digit integer is called "friendly" if in the Problem Solving forum
“Total number of friendly numbers = total number of ways to arrange the 5 digits = 5! = 120. There are 5 options for the first digit: 1, 2, 3, 4, or 5. 120/5 = 24. Thus, the 120 friendly numbers are composed of five 24-number ranges, as follows: The integers beginning with 1 constitute friendly ...”
February 12, 2019
GMATGuruNY posted a reply to How many numbers between 1 and 200, inclusive, have a 2 in in the Problem Solving forum
“An integer is divisible by 4 if its last two digits form a multiple of 4. Two-digit multiples of 4 with a units digit of 2: 12, 32, 52, 72, 92 Since the last two digits must be one of the options above, between 1 and 200 there are 10 integers that have a units digit of 2 and are divisible by 4: ...”
February 12, 2019
GMATGuruNY posted a reply to If triangles ABC and CDE are each equilateral, what is the s in the Data Sufficiency forum
“Statement 1: Case 1: AC = 10 and CE = 15, with the result that AE = 10+15 = 25 In this case, ABC + CDE = (10+10+10) + (15+15+15) = 75. Case 2: AC= 5 and CD = 20, with the result that AE = 5+20 = 25 In this case, ABC + CDE = (5+5+5) + (20+20+20) = 75. Since the sum of the perimeters is the same ...”
February 12, 2019
GMATGuruNY posted a reply to If m is a positive odd integer, what is the average (arithme in the Data Sufficiency forum
“For any EVENLY SPACED SET: average = median Statement 1: Here, the set consists of consecutive multiples of 3 and thus is evenly spaced. Case 1: 3, 6, 9 Average = median = 6. Case 2: 6, 9, 12 Average = median = 9. Since different averages are possible, INSUFFICIENT. Statement 2: Case ...”
February 12, 2019
GMATGuruNY posted a reply to If there is a 20% chance of rain every day for the next 7 in the Problem Solving forum
“Options D and E should appear as shown below: P(exactly n times) = P(one way) * all possible ways. Let R = rain and N = no rain. Since P(R) = 20% = 2/10, P(N) = 80% = 8/10 = 2³/10. P(one way): One way to get exactly 2 days of rain is to have rain on the first 2 days but not on the ...”
February 12, 2019
GMATGuruNY posted a reply to Working together, Machine A and Machine B can produce a tota in the Data Sufficiency forum
“Since A+B take 4 hours to produce 200 widgets, the combined rate for A+B = w/t = 200/4 = 50 widgets per hour. To determine A''s time to produce 200 widgets, we need to know A''s rate. Question stem, rephrased: What is A''s rate? Statement 1: Since B takes 5 hours to produce 50 widgets, ...”
February 10, 2019
GMATGuruNY posted a reply to Triangle XYZ is an isosceles right triangle. If side XY is l in the Problem Solving forum
“The sides of an isosceles right triangle are in the following ratio: x - x - x√2, where x and x constitute the base and height and x√2 is the hypotenuse. Since the triangle has a base of x, a height of x, and an area of 16, we get: (1/2)(x)(x) = 16 x² = 32 x = √32 Since XY is longer ...”
February 9, 2019
GMATGuruNY posted a reply to Machines X and Y work at their respective constant rates. Ho in the Data Sufficiency forum
“Statement 1: Time and rate are RECIPROCALS. Since X and Y together take 2/3 as long as X alone, X and Y together work 3/2 as fast as X alone. Thus, if X''s rate alone = 2 units per hour, then X and Y''s combined rate = (3/2)(2) = 3 units per hour, implying that Y''s rate alone = 3-2 = 1 unit ...”
February 9, 2019
GMATGuruNY posted a reply to Seven children — A, B, C, D, E, F, and G — are going to in the Problem Solving forum
“Since A and B must occupy adjacent positions, consider AB a single element in the arrangement. The number of ways to arrange the 6 elements AB, C, D, E, F and G = 6! = 720. In 1/2 of these arrangements, C will be to the LEFT of AB. In the remaining 1/2 of these arrangements,C will be to the ...”
February 9, 2019
GMATGuruNY posted a reply to Is abc at least 4? in the Data Sufficiency forum
“Nice problem, Fabio! Statement 1: Case 1: a=4, b=1 and c=1, with the result that b+c≥2 In this case, abc = 4, so the answer to the question stem is YES. Case 2: a=0, b=1 and c=1, with the result that b+c≥2 In this case, abc = 0, so the answer to the question stem is NO. Since the answer ...”
February 8, 2019
GMATGuruNY posted a reply to What is the remainder when the positive integer n is divided in the Data Sufficiency forum
“Statement 1: If n=5, then the remainder when n is divided by 6 = 5/6 = 0 R5. If n=10, then the remainder when n is divided by 6 = 10/6 = 1 R4. Since different remainders are possible, INSUFFICIENT. Statement 2: Since n is a multiple of 12, n must also be a multiple of 6, with the result that ...”
February 8, 2019
GMATGuruNY posted a reply to An electrical supplies store sells 140 power stabilizer in the Problem Solving forum
“Since at least $5600 in profit must be earned by 140 units, the minimum required markup per unit = 5600/140 = $40. Thus, the minimum selling price = (cost per unit) + (minimum required markup per unit) = 16+40 = 56. The correct answer is D.”
February 8, 2019
GMATGuruNY posted a reply to In the xy coordinate plane, line L and line K intersect at in the Data Sufficiency forum
“Statement 1: The product of the x-intercepts of line L and K is positive. K has a negative x-intercept, L has a negative x-intercept, the product of the slopes is positive: http://s4.postimage.org/ie5nbe78/lines_l_and_k_1.jpg K has a positive x-intercept, L has a positive x-intercept, the ...”
February 8, 2019
GMATGuruNY posted a reply to If x and y are positive integers, is x an even integer? in the Data Sufficiency forum
“Statements combined: Case 1: x=1 and y=1, with the result that x(y+5) = 6 and 6y²+41y+25 = 72 In this case, x is ODD, so the answer to the question stem is NO. Case 2: x=2 and y=1, with the result that x(y+5) = 12 and 6y²+41y+25 = 72 In this case, x is EVEN, so the answer to the question ...”
February 7, 2019
GMATGuruNY posted a reply to What is the average (arithmetic mean) of x and y? in the Data Sufficiency forum
“SUM = (COUNT)(AVERAGE). Statement 1: x+y+k = (count)(average) = 3*7 = 21. No way to determine the value of x+y. INSUFFICIENT. Statement 2: x+y+3k = (count)(average) = 3*13 = 39. No way to determine the value of x+y. INSUFFICIENT. Statements combined: Subtracting x+y+k=21 from ...”
February 7, 2019
GMATGuruNY posted a reply to If a and b are integers, is a + b + 3 an odd integer? (1) in the Data Sufficiency forum
“a+b+3 = ODD only if a and b are both odd or both even. Question stem, rephrased: Are a and b both odd or both even? Statement 1: ab = ODD implies that a and b are both odd. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: a-b = EVEN implies that a and b are either ...”
February 7, 2019
GMATGuruNY posted a reply to In the coordinate plane, Line A has a slope of -1 and an in the Problem Solving forum
“Line A includes points (1, 0) and (a, b) and has a slope of -1. Thus: (b - 0)/(a-1) = -1 b = -a + 1 a+b = 1. The correct answer is B. The information about Line B is irrelevant.”
February 5, 2019
GMATGuruNY posted a reply to In how many ways can a 4-letter word be formed from the in the Problem Solving forum
“Alternate approach: Case 1: VVCC, where the first two letters are vowels and the last 2 letters are consonants Number of options for the first vowel = 4. (Any of the 4 vowels) Number of options for the second vowel = 3. (Any of the 3 remaining vowels) Number of options for the first consonant ...”
February 5, 2019
GMATGuruNY posted a reply to A contractor combined x tons of a gravel mixture that in the Data Sufficiency forum
“x = 10% gravel y = 2% gravel. z = the MIXTURE of x and y = 5% gravel. To determine the required ratio of x to y, use ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: Plot the 3 percentages on a number line, with the percentages for x and y on the ends and the ...”
February 4, 2019
GMATGuruNY posted a reply to Bank Depositors (GMAT Prep) in the Critical Reasoning forum
“I received a PM requesting that I respond. Premise: Insurance removes from depositors any financial incentive to find out whether the bank that holds their money is secure against failure. Conclusion: The insurance is partly responsible for the high rate of bank failures. To determine the ...”
February 3, 2019
GMATGuruNY posted a reply to In the graduating class of a certain college, 48 percent of in the Problem Solving forum
“Every student is EITHER male OR female. Every student is EITER older OR younger. For an EITHER/OR problem, use a DOUBLE MATRIX to organize the data: _______________M______F_______Total older: younger: total: Let total students = 100: _______________M______F_______Total ...”
February 3, 2019
GMATGuruNY posted a reply to Kate and Danny each have $10. Together, they flip a fair coi in the Problem Solving forum
“For every tails, Kate gets $1; for every heads, she loses $1. 0 tails, 5 heads: Kate has 10+0-5 = $5 1 tails, 4 heads: Kate has 10+1-4 = $7 2 tails, 3 heads: Kate has 10+2-3 = $9 3 tails, 2 heads: Kate has 10+3-2 = $11 4 tails, 1 heads: Kate has 10+4-1 = $13 5 tails, 0 heads: Kate has ...”
February 3, 2019
GMATGuruNY posted a reply to A paint crew gets a rush order to paint 80 houses in a new d in the Problem Solving forum
“Let y=0, implying that NONE of the 80 houses are painted at the original rate of x houses per week, with the result that ALL 80 houses are painted at the greater rate of (5/4)x houses per week. The total time it takes them to paint all the houses under this scenario is what fraction of the time ...”
February 1, 2019
GMATGuruNY posted a reply to Three pipes P, Q, and R are attached to a tank. P and Q indi in the Problem Solving forum
“Let the tank = 60 liters. Since P takes 3 hours to fill the 60-liter tank, P''s rate = 60/3 = 20 liters per hour. Since Q takes 4 hours to fill the 60-liter tank, Q''s rate = 60/4 = 15 liters per hour. Since R takes 5 hours to empty the 60-liter tank, R''s rate = -(60/5) = −12 liters per ...”
February 1, 2019
GMATGuruNY posted a reply to If ( x – y – 2 )^2 + ( x + z + 3 )^2 = 0, then what is t in the Problem Solving forum
“Let x=0. Plugging x=0 into (x-y-2)² + (x+z+3)² = 0, we get: (-y-2)² + (z+3)² = 0 Since neither (-y-2)² nor (z+3)² can be negative, the resulting equation is valid only if -y-2=0 and z+3=0, with the result that y=-2 and z=-3. Thus, y+z = -2 + (-3) = -5 The correct answer is E.”
February 1, 2019
GMATGuruNY posted a reply to Cars J and K are making the trip from City A to City B. Car in the Problem Solving forum
“Since J catches up to K, J and K travel the same distance. Let t = J''s time. Since K leaves 15 minutes earlier than J, K''s time = t+15. Rate and time have a RECIPROCAL RELATIONSHIP. Since K''s rate is 80% of J''s rate, the ratio of K''s rate to J''s rate = 8/10 = 4/5. Thus, the ratio of ...”
January 31, 2019
GMATGuruNY posted a reply to f(2x-1) = ( x + 2 ) / ( x – 2 ). What is f(x)? in the Problem Solving forum
“Let x=1. Plugging x=1 into f(2x-1) = ( x + 2 ) / ( x – 2 ), we get: f(2*1 - 1) = (1+2)/(1-2) f(1) = -3. When x=1, the question stem becomes: What is f(1)? Since f(1) = -3, the correct answer must yield -3 when x=1. Only A works: f(1) = (1+5)/(1-3) = 6/-2 = -3. The correct answer is A.”
January 31, 2019
GMATGuruNY posted a reply to A lecture course consists of 595 students. The students are in the Problem Solving forum
“(students per section)(number of sections) = 595 students number of sections = 595/(students per section). The equation in blue indicates that 595 must be divisible by the number of students per section. An integer is divisible by 3 only if its digit sum is a multiple of 3. The digit sum of ...”
January 30, 2019
GMATGuruNY posted a reply to Question about idioms and verbs in the Sentence Correction forum
“Correct: The contractors demolished the building to keep it from falling. Here, to keep is not an adjective modifying contractors but an ADVERB modifying demolished, expressing WHY the contractors DEMOLISHED the building. Question: WHY did the contractors demolish the building? Answer: TO KEEP it ...”
January 30, 2019
GMATGuruNY posted a reply to DS work rate problem in the Data Sufficiency forum
“Statement 1: Case 1: Job = 12 units Since A and B together take 4 hours to complete the 12-unit job, the combined rate for A+B = 12/4 = 3 units per hour. Since A alone takes 6 hours to complete the 12-unit job, A''s rate alone = 12/6 = 2 units per hour. B''s rate = (combined rate for A+B) - ...”
January 30, 2019
GMATGuruNY posted a reply to PS arithmetic in the Problem Solving forum
“An alternate approach is to BALLPARK. √2 ≈ 1.4 √3 ≈ 1.7 (1+√3) * √(2 + √3) ≈ (2.7)(√3.7) = (2.7)(a bit less than 2) = a bit less than 5.4. When we evaluate the answer choices, only C is a bit less than 5.4: √2(2 + √3) ≈ (1.4)(3.7) = 5.18. The correct answer is C.”
January 30, 2019
GMATGuruNY posted a reply to DS arithmetic in the Data Sufficiency forum
“Statement 1: The inequality implies that a is POSITIVE, allowing us to cross-multiply: 1*2 > a*1 2 > a Since 2>a and a>b>0, we get: 2>a>b>0 Thus, b<2. SUFFICIENT. Statement 2: If b=2, we get: 1/a + 1/2 = 1 1/a = 1/2 a=2 Not possible, since the prompt ...”
January 30, 2019
GMATGuruNY posted a reply to The sum of 4 different odd integers is 64. in the Data Sufficiency forum
“Statement 1: Since the numbers are EVENLY SPACED, median = sum/count: 64/4 = 16. Since the median = 16, the 4 odd integers must be as follows: 13, 15, 17, 19. Thus, the greatest of the 4 odd integers = 19. SUFFICENT. Statement 2: The 4 odd integers yielded by Statement 1 -- 13, 15, ...”
January 30, 2019
GMATGuruNY posted a reply to To create a part for a certain piece of machinery, four equa in the Problem Solving forum
“The four 18-degree shaded regions = 4*18 = 72 degrees. The entire circle = 360 degrees. (shaded regions)/(entire circle) = 72/360 = 1/5. Thus: (unshaded regions)/(entire circle) = 1 - 1/5 = 4/5 = 80%. The correct answer is E.”
January 29, 2019
GMATGuruNY posted a reply to When 12 marbles are added to a rectangular aquarium, the wat in the Problem Solving forum
“The desired height increase = 11/4 inches. 12 marbles yield a height increase of 3/2 inches. Thus: (desired height increase of 11/4 inches) * (12 marbles)/(height increase of 3/2 inches) = (11/4 * 12)/(3/2) = 33/(3/2) = (33*2)/3 = 11*2 = 22 marbles. The correct answer is D.”
January 28, 2019
GMATGuruNY posted a reply to A certain company has 18 equally qualified applicants for 4 in the Problem Solving forum
“From 18 applicants, the number of ways to choose 4 = 18C4 = (18*17*16*15)/(4*3*2*1) = (3*17*4*15) = 51*60 = 3060. The correct answer is E.”
January 28, 2019
GMATGuruNY posted a reply to A new tower has just been built at the Verbico military in the Problem Solving forum
“Let the PRE-TOWER number of beds = the LCM of the denominators in the problem = 3*5 = 15. Then the CURRENT number of beds = 3*15 = 45, implying that the number of beds in the NEW tower = 45-15 = 30. Occupied beds = (1/3)15 + (1/5)30 = 11. Non-occupied beds in the new tower = 30-11 = 19. ...”
January 28, 2019
GMATGuruNY posted a reply to Machines A and B, working together, take t minutes to in the Problem Solving forum
“One more approach: Since A+B together complete the job in t minutes: Job = (A''s output in t minutes) + (B''s output in t minutes) If A works alone for t minutes, A can then complete the rest of the job in 64 minutes. In this case, the rest of the job = B''s output in t minutes. Thus, A''s ...”
January 27, 2019
GMATGuruNY posted a reply to Prompted by observations of seemingly related species in the Sentence Correction forum
“A present perfect verb (has + VERBed or have + VERBed) expresses a PAST ACTION that affects the present. Generally, the usage of a present perfect verb implies that the subject of the verb still exists. Incorrect: The dinosaurs have evolved over time. The sentence above is illogical because the ...”
January 27, 2019
GMATGuruNY posted a reply to Machines A and B, working together, take t minutes to in the Problem Solving forum
“Always keep your eye on the answer choices. Since A''s time alone (t+64) is greater than B''s time alone (t+25), the ratio of A''s time alone to B''s time alone must be GREATER THAN 1. Eliminate A, C and D. Since the ratio of A''s time to B''s time = (t+64)/(t+25), option E implies the ...”
January 27, 2019
GMATGuruNY posted a reply to A certain library assesses fines for overdue books as in the Problem Solving forum
“First day: Total fine = 10. For each additional day, the total fine either increases by 30 or doubles -- whichever results in a lesser amount. Second day: Adding 30 cents to the 1-day fine, we get 10+30 = 40. Doubling the 1-day fine, we get 2*10 = 20. Total fine = lesser amount = 20. ...”
January 27, 2019
GMATGuruNY posted a reply to If the drama club and music club are combined, what percent in the Data Sufficiency forum
“Clearly, neither statement alone is sufficient. Statements combined: Case 1: No one is a member of both clubs Total males = 15+10 = 25. Total members = 16+20 = 36. Resulting fraction: (total males)/(total members) = 25/36. Case 2: Every male in the music club is also in the drama ...”
January 26, 2019
GMATGuruNY posted a reply to Frank and Georgia started traveling from A to B at the same in the Problem Solving forum
“Let d = the number of miles between A and B. Since Georgia travels the entire d miles between A and B and then an additional 60 miles back toward A, Georgia''s distance = d+60. Since Frank travels all but 60 of the d miles between A and B, Frank''s distance = d-60. Since Georgia''s travels 3/2 ...”
January 26, 2019
GMATGuruNY posted a reply to Ratio in the Problem Solving forum
“Let S = the entire season (in other words, the mixture of M and N). Alligation can be performed only with percentages or fractions. Step 1: Convert the ratios to FRACTIONS. M: Since win:losses = 1:2, and 1+2=3, wins/total = 1/3. N: Since wins:losses = 1:3, and 1+3=4, wins/total = 1/4. ...”
January 25, 2019
GMATGuruNY posted a reply to How many factors greater than 1 do 120, 210, and 270 have in in the Problem Solving forum
“120 = 30*4 210 = 30*7 270 = 30*9 The GCF = the value in blue = 30. Factors of 30 greater than 1: 2, 3, 5, 6, 10, 15, 30 --> 7 factors Thus, 120, 210, and 270 have 7 common factors greater than 1. The correct answer is D.”
January 24, 2019
GMATGuruNY posted a reply to Stacy and Katie plan to walk the 27-mile scenic route across in the Problem Solving forum
“Since Stacy and Katie travel toward each other, they WORK TOGETHER to cover the 27 miles between them. Since Stacy is 1/4 faster than Katie, for every 4 miles that Katie travels, the distance traveled by Stacy = 4 + (1/4)(4) = 5 miles. Thus, of every 9 miles traveled when Stacy and Katie work ...”
January 24, 2019
GMATGuruNY posted a reply to If when a certain integer x is divided by 5, the remainder in the Problem Solving forum
“Since dividing x by 5 yields a remainder, x is not a multiple of 5 and thus not a multiple of 10. Since x is not a multiple of 10, x/10 cannot yield an integer value. The correct answer is B.”
January 22, 2019
GMATGuruNY posted a reply to Mary and Kate are running clockwise around a circular track in the Problem Solving forum
“Since Mary is behind Kate by 250 meters -- half the circumference of the track -- she will catch up to Mary when she has traveled 250 meters more than Kate. To catch up to Kate a second time, Mary must then travel one more lap than Kate -- in other words, 500 meters more than Kate. Implication: ...”
January 22, 2019
GMATGuruNY posted a reply to If y=|x-1|+|x+1|, then y=? in the Data Sufficiency forum
“|x-1| = the distance between x and 1. |x+1| = the distance between x and -1. -1<--|x+1|-->x<--|x-1|-->1 Here, since the total distance between the two endpoints is 2, the sum of the 2 distances in red is 2. If x is any value between the two endpoints, then the sum of the two ...”
January 22, 2019
GMATGuruNY posted a reply to A = (2-3+4)^{11}, and B = (-2+3-4)^{11}. What is the value o in the Problem Solving forum
“A = (2-3+4)¹¹ = 3¹¹ B = (-2+3-4)¹¹ = (-3)¹¹ = -3¹¹ Thus: A+B = 3¹¹ - 3¹¹ = 0 2^(A+B) = 2⁰ = 1. The correct answer is C.”
January 22, 2019
GMATGuruNY posted a reply to GMAT OG 2019 The Commerce Department reported that in the Sentence Correction forum
“were + VERBing is the plural form of the PAST PROGRESSIVE tense (also known as the past continuous tense). The past progressive tenses serve to express actions that happen CONTINUOUSLY FOR A LIMITED DURATION OF TIME. OA: While businesses were expanding their production, unsold goods were piling ...”
January 22, 2019
GMATGuruNY posted a reply to Machine A produces pencils at a constant rate of 9000 in the Problem Solving forum
“To minimize B''s time, we must maximize A''s time. Since each machine can work for at most 8 hours, let A''s time = 8 hours. Since A''s rate = 9000 pencils per hour, the number of pencils produced by A in 8 hours = rt = 9000*8 = 72,000. Remaining pencils = 100,000 - 72,000, = 28,000. Since ...”
January 21, 2019
GMATGuruNY posted a reply to A bowl contains pecans, cashews, and almonds in a ratio of 6 in the Problem Solving forum
“Original ratio values: P.................................................C...............................................A 6x<---distance of 4x--->10x<---distance of 5x--->15x Options for the new ratio: I) 1 : 2 : 3 I) 2 : 3 : 4 III) 4 : 7 : 10 The ratio values in each ...”
January 21, 2019
GMATGuruNY posted a reply to If x-2y=4, then x^2-4xy+4y^2-x+2y=? in the Problem Solving forum
“Let x=4 and y=0, with the result that x-2y = 4. Plugging x=4 and y=0 into x² - 4xy + 4y² - x + 2y, we get: 4² - 0 + 0 - 4 + 0 = 12. The correct answer is A.”
January 21, 2019
GMATGuruNY posted a reply to A company bought some desks at a price of $150 each and some in the Data Sufficiency forum
“Test the THRESHOLD. In the question stem, the threshold is 40 CHAIRS. The total cost of 40 chairs = 40*50 = 2000. Statement 1: The total price of the desks and chairs is 5,000. It is possible that 40 chairs are purchased (at a total cost of $2000) or that MORE CHAIRS are purchased. ...”
January 20, 2019
GMATGuruNY posted a reply to What is the value of x? in the Data Sufficiency forum
“Statement 1: To have exactly 3 positive factors, x must be the square of a prime number. Factors of x=2²=4: 1, 2, 4 Factors of x=3²=9: 1, 3, 9 Factors of x=5²=25: 1, 5, 25. Since x can be different values, INSUFFICIENT. Statement 2: Clearly INSUFFICIENT. Statements combined: x ...”
January 20, 2019
GMATGuruNY posted a reply to The average American spends y dollars on food per month, exc in the Problem Solving forum
“Monthly food expense except in January: Let y=$2. Discount in January: Let x=100%. Since $2 is spent each month for 8 of the first 9 months, the total spent during these 8 months = 8*2 = 16. Since food purchases are 100% lower in January -- implying that they are FREE in January -- the amount ...”
January 20, 2019
GMATGuruNY posted a reply to In a certain pet shop, 1/3 of the pets are dogs and 1/5 of in the Data Sufficiency forum
“Alternate approach: To determine the ratio of birds to dogs, plug in a TEST VALUE for the total number of pets. Let b = the number of birds and d = the number of dogs. Let the test value for the total number of pets = the LCM of 3 and 5 = 15. Since 1/5 are birds, b = 1/5 * 15 = 3. Since 1/3 ...”
January 19, 2019
GMATGuruNY posted a reply to How many hours did it take Helen to drive from her house to in the Data Sufficiency forum
“Statement 1: If d=72, then t = d/r = 72/72 = 1 hour. If d=144, then t = 144/72 = 2 hours. Since the time can be different values, INSUFFICIENT. Statement 2: Time and rate have a RECIPROCAL RELATIONSHIP: If the time is cut in HALF, then the rate DOUBLES. If the time DOUBLES, then the ...”
January 18, 2019
GMATGuruNY posted a reply to If tank X contains only gasoline, how many kiloliters of gas in the Data Sufficiency forum
“Let G = the gas in the tank and C = the capacity of the tank. Statement 1: G - (1/2)G = (1/3)C No way to solve for G. INSUFFICENT. Statement 2: G + 0.75 = C No way to solve for G. INSUFFICIENT. Statements combined: Since we have two variables (G and C) and two distinct linear ...”
January 18, 2019
GMATGuruNY posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“Here, the value in red is the sum of Jake''s weight and TWICE the sister''s weight: 187 + 2(89.5) = 366. But the prompt gives an integer value for the sum of Jake''s weight and the sister''s ACTUAL weight -- a constraint that forces Jake''s weight to be an even integer.”
January 17, 2019
GMATGuruNY posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“The sum of Jake''s weight and his sister''s weight is an INTEGER VALUE. The answer choices indicate that Jake''s weight is an INTEGER VALUE. Implication: The sister''s weight must also be an integer value. Thus, the value in red -- 89.5 -- is not a valid option for the sister''s weight. Given ...”
January 17, 2019
GMATGuruNY posted a reply to The speed of a boat is 5 times the speed at which a river fl in the Problem Solving forum
“Let the river''s rate = 1 mph and the boat''s rate = 5 mph. When the boat travels DOWNRIVER, the boat and the river WORK TOGETHER, so we ADD their rates: 5+1 = 6 mph. When the boat travels UPRIVER, the boat and the river COMPETE, so we SUBTRACT their rates: 5-1 = 4 mph. Rate and time have ...”
January 17, 2019
GMATGuruNY posted a reply to If Jake loses 8 pounds, he will weigh twice as much as his s in the Problem Solving forum
“ALWAYS KEEP YOUR EYE ON THE ANSWER CHOICES. If Jake loses 8 pounds, he will weigh twice as much as his sister. j-8 = 2s j = 2s + 8 = even + even = even. Since Jake''s weight must be an EVEN VALUE, the correct answer is E.”
January 17, 2019
GMATGuruNY posted a reply to Sarah is in a room with 6 other children. If the other child in the Data Sufficiency forum
“Let S = Sara''s age. Sum of the ages = 2+4+5+8+10+13+S = 42+S. Statement 1: Since the average age is equal to an INTEGER -- the fourth largest age -- we get: Sum of the ages = (number of ages)(average age) = (7)(INTEGER) = multiple of 7. The blue expression and the red expression each ...”
January 16, 2019
GMATGuruNY posted a reply to If the median and the range of the data set 1, 1, 2, 2, 3, 3 in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of m. When the correct answer is plugged in, the median will be equal to the range. Note: When the prompt includes the phrase which of the following, the correct answer is likely to be D or E. E: m=3 Resulting set: 1, 1, 2, 2, m=3, 3, 3, ...”
January 16, 2019
GMATGuruNY posted a reply to Henry eats X scones in X percent of the time it takes Rachel in the Problem Solving forum
“Let X=8 and Y=4. Henry eats X scones in X percent of the time it takes Rachel to eat Y scones. Since Henry eats X=8 scones in 8% of the time it takes Rachel to eat Y=4 scones -- 10 minutes, according to the prompt -- the time for Henry to eat 8 scones = 8% of 10 minutes = (8/100)(10) = 4/5 ...”
January 15, 2019
GMATGuruNY posted a reply to A rectangular wall has dimensions of 800 by 300. If the wall in the Problem Solving forum
“number of tiles = (wall area)/(tile area) = (800*300)/(25*12) = 32*25 = 800. The correct answer is E.”
January 15, 2019
GMATGuruNY posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum
“Consider the following equation: 7x + 5y = 70. If x and y are nonnegative integers, the following solutions are possible: x=10, y=0 x=5, y=7 x=0, y=14. Notice the following: The value of x changes in increments of 5 (the coefficient for y). The value of y changes in increments of ...”
January 15, 2019
GMATGuruNY posted a reply to The cost of a square slab is proportional to its thickness a in the Data Sufficiency forum
“x is directly proportional to y implies the following: x/y = k. x = ky. In each case, k is a CONSTANT. The cost of a square slab is proportional to its thickness and also proportional to the square of its length. Thus: c = k * T * L². What is the cost of a square slab that is 3 meters ...”
January 15, 2019
GMATGuruNY posted a reply to Thomasville tree planting in the Critical Reasoning forum
“species may be singular or plural. Passage: Planting trees primarily from the species that turns out to have the best record of survival will assure downtown Thomasville of an abundant tree population 20 years from now. Here, the verb attributed to species is turns. Since turns is singular, ...”
January 14, 2019
GMATGuruNY posted a reply to Three machines have equal constant work rates. It takes h + in the Problem Solving forum
“(number of machines)(number of hours) = number of toys that are produced. In the prompt above, the blue values are THE SAME. Implication: 2 machines take h+3 hours to produce the same number of toys as 3 machines in 2 hours: 2(h+3) = 3h 2h + 6 = 3h 6 = h. Since 3 machines produce 360 toys ...”
January 14, 2019
GMATGuruNY posted a reply to If Jay has 99 problems, in how many ways can he select k of in the Data Sufficiency forum
“Rule: nCr = nC(n-r) Examples: 5C2 = 5C(5-2) = 5C3. 10C3 = 10C(10-3) = 10C7. 99C5 = 99C(99-5) = 99C94. Statement 2: Jay can select k-1 of his problems in 4851 different ways. Since 4851 is relatively small, test small values for k-1. Case 1: k-1 = 2 From 99 problems, the number of ...”
January 14, 2019
GMATGuruNY posted a reply to A tank has two water pumps Alpha and Beta and one drain Gamm in the Problem Solving forum
“Let x = 2 hours, y = 3 hours and z = 4 hours. Let the tank = 12 gallons. Since Alpha takes 2 hours to fill the 12-gallon tank, Alpha''s rate = w/t = 12/2 = 6 gallons per hour. Since Beta takes 3 hours to fill the 12-gallon tank, Beta''s rate = w/t = 12/3 = 4 gallons per hour. Since Gamma takes ...”
January 13, 2019
GMATGuruNY posted a reply to To furnish a room in model home, an interior decorator is to in the Problem Solving forum
“Since 150 combinations are possible, we get: (number of ways to choose 2 chairs)(number of ways to choose 2 tables) = 150. From 5 chairs, the number of ways to choose 2 = 5C2 = (5*4)/(2*1) = 10. Thus: (10)(number of ways to choose 2 tables) = 150 number of ways to choose 2 tables = 150/10 = ...”
January 11, 2019
GMATGuruNY posted a reply to Carlos runs a lap around the track in x seconds. His second in the Problem Solving forum
“Let x = 5 seconds for the first lap, implying 10 seconds for the second lap, 3 seconds for the third lap, and a total of 18 seconds for all 3 laps. (18 seconds)/(3 laps) = (6 seconds)/(1 lap) = 1/10 minute per lap. The correct answer must yield a value of 1/10 when x=5. Only D works: (x+1)/60 ...”
January 11, 2019
GMATGuruNY posted a reply to Every day in the morning Ross cycles for 2 hours. He always in the Problem Solving forum
“The information in red is irrelevant. Only the following facts matter: Ross travels onward at a rate of 1 mile every 12 minutes. He travels home for twice the onward distance at half the onward speed. Onward speed = 1 mile per 12 minutes = 5 miles per 60 minutes = 5 mph. Let the onward ...”
January 11, 2019
GMATGuruNY posted a reply to At a certain fruit stand, the price of each apple is 40 in the Problem Solving forum
“The original total cost of the 10 pieces of fruit = 10*56 = 560. According to the answers, after 1, 2, 3, 4, or 5 oranges are removed -- so that 9, 8, 7, 6, or 5 pieces of fruit remain -- the average cost per piece decreases to 52. Since the original total cost is a multiple of 10, and the price ...”
January 11, 2019
GMATGuruNY posted a reply to This year, x people won an Olympic medal for water in the Problem Solving forum
“Let x = the product of the two denominators in the prompt = 3*4 = 12. Since 1/3 won a medal for swimming, the number who won a medal for swimming = (1/3)(12) = 4. Since 1/4 of the medal winners for swimming also won a medal for diving, the number who won both a medal for swimming and a medal for ...”
January 10, 2019
GMATGuruNY posted a reply to (7+43+7-43)^2 is equal to which of the following? in the Problem Solving forum
“√3 ≈ 1.7. 7 + 4√3 ≈ 7 + (4)(1.7) = 13.8. 7 - 4√3 ≈ 7 - (4)(1.7) = 0.2. Thus, the given expression can be approximated as follows: (√13.8 + √0.2)² = a little more than 13.8. Only D is viable. The correct answer is D.”
January 10, 2019
GMATGuruNY posted a reply to PLease help me with the concept! in the Sentence Correction forum
“Offhand, I cannot cite an official SC that violates the rule discussed above.”
January 10, 2019
GMATGuruNY posted a reply to What is the greatest possible area of a triangular region in the Problem Solving forum
“Given two sides of a triangle, the greatest possible area will be achieved if the two sides form a RIGHT ANGLE and serve as the triangle''s base and height. For the problem above, I posted an illustrated solution here: ...”
January 9, 2019
GMATGuruNY posted a reply to Stock - Number of shares V ------------------- 68 W ------- in the Problem Solving forum
“Original range = (greatest number of shares) - (smallest number of shares) = 112-45 = 67. After 24 shares of Y are purchased, new Y = 94+24 = 118. After 20 shares of X are sold, new X = 56-20 = 36. New range = (new greatest number of shares) - (new smallest number of shares) = 118-36 = 82. ...”
January 9, 2019
GMATGuruNY posted a reply to On a certain Monday, Carlos drove to work at an average in the Problem Solving forum
“When the SAME DISTANCE is traveled at two different speeds, the average speed for the entire trip will be CLOSER TO THE LOWER SPEED than to the higher speed. The reason: The portion traveled at the lower speed takes LONGER. Since more time is spent at the lower speed than at the higher speed, the ...”
January 8, 2019
GMATGuruNY posted a reply to A department manager distributed a number of pens, pencils, in the Data Sufficiency forum
“Statement 1: The numbers of pens, pencils, and pads that each staff member received were in the ratio 2:3:4, respectively. Since 2+3+4 = 9, the total number of pens + pencils + pads must be a multiple of 9. No way to determine the exact number of staff members. INSUFFICIENT. Statement 2: ...”
January 8, 2019
GMATGuruNY posted a reply to Because natural gas is composed mostly of methane in the Sentence Correction forum
“Both of the following are viable: Vehicles powered by natural gas emit less of certain pollutants than those burning gasoline or diesel fuel. Vehicles powered by ndatural gas emit less of certain pollutants than do those burning gasoline or diesel fuel. The inclusion of do is optional. With or ...”
January 8, 2019
GMATGuruNY posted a reply to If the graph of y = x^2 + ax + b passes through the points ( in the Data Sufficiency forum
“What is the value of n-m? (m,0) and (n,0) are the two points where y=0 and the graph intersects the x-axis. Thus, m and n are the x-intercepts of the graph. Since m < n, n-m > 0. Question rephrased: What is the positive difference between the x-intercepts? Statement 1: 4b = a²-4 Test ...”
January 8, 2019
GMATGuruNY posted a reply to If x is integer and 3 | x |+x < 4, what is the value of x in the Data Sufficiency forum
“3|x| < 4-x Case 1: Signs unchanged 3x < -x 4x < 4 x < 1 Case 2: Signs changed in the absolute value 3(-x) < 4-x -2x < 4 x > -2 Question stem, rephrased: If x is an integer such that -2 < x < 1, what is the value of x? Statement 1: x < 0 Here, x must ...”
January 8, 2019
GMATGuruNY posted a reply to In 1991, the price of a house was 80% of its original price. in the Problem Solving forum
“Let the original price = 100. 1991 price = 80% of 100 = 80. 1992 price = 60% of 100 = 60. Percent decrease from 80 to 60 = (Difference/Larger) * 100 = (20/80) * 100 = 25. The correct answer is B.”
January 7, 2019
GMATGuruNY posted a reply to The main ingredient in a certain prescription drug capsule c in the Problem Solving forum
“Each capsule contains 600 milligrams of ingredient. 10⁶ milligrams = 1 kilogram. 1 kilogram of ingredient = 500 dollars. To determine the cost per capsule, we must use the relationships above to convert 600 milligrams into dollars: (600 milligrams) * (1 kilogram)/(10⁶ milligrams) * ...”
January 7, 2019
GMATGuruNY posted a reply to The numbers of women is singular or plural? in the Sentence Correction forum
“percent may serve as a NOUN. Of the students in the class, eighty percent passed the test. Here, eighty percent is a NOUN serving as the subject of passed. twice is a MODIFIER. It cannot serve as the subject of a sentence. Of the students in the class, twice passed the test. The sentence ...”
January 7, 2019
GMATGuruNY posted a reply to If f(a*b) = f(a) + f(b), what is the value of f(1)? in the Problem Solving forum
“Let a=1 and b=2. Plugging a=1 and b=2 into f(ab) = f(a) + f(b), we get: f(1*2) = f(1) + f(2) f(2) = f(1) + f(2) 0 = f(1). The correct answer is C.”
January 7, 2019
GMATGuruNY posted a reply to A store sells erasers for 0.23$ per piece and pencil for in the Data Sufficiency forum
“Consider the following equation: 5x + 7y = 70. If x and y are nonnegative integers, the following solutions are possible: x=0, y=10 x=7, y=5 x=14, y=0. Notice the following: The value of x changes in increments of 7 (the coefficient for y). The value of y changes in increments of 5 (the ...”
January 6, 2019
GMATGuruNY posted a reply to the mixture to make the ratio of milk and water in the new m in the Problem Solving forum
“The ratio of milk and water in a mixture is 2:1, Let milk = 2 liters and water = 1 liter. Some quantity of water is added to the mixture to make the ratio of milk and water in the new mixture 1:2. Since the resulting amount of water must be double the original 2 liters of milk, the resulting ...”
January 6, 2019
GMATGuruNY posted a reply to Little Texas Drilling Company has three wells, each producin in the Problem Solving forum
“Given the answer choices, the prompt should read as follows: A''s rate = (1 barrel)/(2 minutes) * (60 minutes)/(1 hour) = 30 barrels per hour. B''s rate = (1 barrel)/(3 minutes) * (60 minutes)/(1 hour) = 20 barrels per hour. C''s rate = (1 barrel)/(15 minutes) * (60 minutes)/(1 hour) = 15 ...”
January 6, 2019
GMATGuruNY posted a reply to If y = |2 + x| - |2 – x| and |2x – 15| < 2, how many in the Problem Solving forum
“|a-b| = the distance between a and b |a+b| = |a-(-b)| = the distance between a and -b y = |2 + x| - |2 – x| y = |x+2| - |x-2| y = |x-(-2)| - |x-2| y = the subtraction of two distances: (distance between x and -2) - (distance between x and 2) On the number line: ...”
January 5, 2019
GMATGuruNY posted a reply to Seven cars of seven different models are going to park in in the Problem Solving forum
“Let the 7 cars be A, B, C, D, P, Q and S. Since P and Q must occupy adjacent positions, consider PQ a single element in the arrangement. The number of ways to arrange the 6 elements A, B, C, D, PQ and S = 6! = 720. In 1/2 of these arrangements, S will be to the LEFT of PQ. In the ...”
January 5, 2019
GMATGuruNY posted a reply to Which of the following must be non-negative? in the Problem Solving forum
“D: (a-0.9)(a-0.9) = (a-0.9)². The square of a value cannot be negative. The correct answer is D.”
January 5, 2019
GMATGuruNY posted a reply to Machine M and Machine N working alone at their constant rate in the Data Sufficiency forum
“Statement 1: Case 1: N = 4000 nails per hour, M = 2000 nails per hour Since N''s rate = 4000 nails per hour, the time for N to produce 8000 nails = 8000/4000 = 2 hours. Since M''s rate = 2000 nails per hour, the time for M to produce 6000 nails = 6000/2000 = 3 hours. In this case, M works longer ...”
January 5, 2019
GMATGuruNY posted a reply to Each of the 25 balls in a certain box is either red, blue, in the Data Sufficiency forum
“Let: W = the total number of white marbles. E = the total number of even marbles. WE = the total number of white even marbles. Statement 1: Thus, WE = 0. No way to determine the value of W or E. INSUFFICIENT. Statement 2: Implication: W-E = (0.2)(25) = 5. Case 1: W=10, E=5, WE=0 ...”
January 4, 2019
GMATGuruNY posted a reply to Allison always leaves her office at 5.00pm and reaches her in the Data Sufficiency forum
“Statement 2: Brittany always leaves the hotel at exactly 5.30pm. To see the situation more clearly, plug in a value for the distance between the hotel and the office. Let the distance = 6 miles. Since Allison takes 1 hour -- from 5 to 6pm -- to travel the entire distance, Alison''s rate = d/t = ...”
January 4, 2019
GMATGuruNY posted a reply to If y = 2 + 2K and y≠0y≠0, then 1/y + 1/y + 1/y + 1/y = ? in the Problem Solving forum
“Let k=0, implying that y = 2 + 2*0 = 2. Plugging y=2 into 1/y + 1/y + 1/y + 1/y, we get: 1/2 + 1/2 + 1/2 + 1/2 = 2. The correct answer must yield a value of 2 when k=0. Only B works: 2/(1+k) = 2/(1+0) = 2. The correct answer is B.”
January 4, 2019
GMATGuruNY posted a reply to OG Verbal 2016-SC# 63 in the Sentence Correction forum
“In my previous response, I provided links to three official examples. This construction seems viable.”
January 4, 2019
GMATGuruNY posted a reply to OG Verbal 2016-SC# 63 in the Sentence Correction forum
“It is possible for back-to-back modifiers joined solely by a comma to have the same referent. Three examples: http://www.beatthegmat.com/the-hognose-snake-puts-on-an-impressive-bluff-t93558.html http://www.beatthegmat.com/parallelism-issue-t96011.html ...”
January 4, 2019
GMATGuruNY posted a reply to In a sports club, 6 players are divided into 3 teams of 2 pl in the Problem Solving forum
“The usage of the term arrangements is misleading. The prompt seems intended to ask the following: The first player selected can be paired with any of the 5 other players. Thus, the number of options for the first player selected = 5. At this point, 4 players remain. The next player ...”
January 4, 2019
GMATGuruNY posted a reply to This morning, a certain sugar container was full. Since then in the Data Sufficiency forum
“The determine the percent decrease, we need to know the RATIO between the remaining amount of sugar after cookie-making and the original amount of sugar. Statement 1: Case 1: Remaining sugar after cookie-making = 10 pounds Since the remaimning amount of sugar would need to increase by 30% to ...”
January 3, 2019
GMATGuruNY posted a reply to Is x/y < 0? in the Data Sufficiency forum
“Question stem, rephrased: Do x and y have different signs? Statement 1: |x+y| < |x|+|y| Since an absolute value cannot be negative, both sides here are NONNEGATIVE, enabling us to safely square the inequality: (|x+y|)²< (|x|+|y|)² x² + y² + 2xy < x² + y² + 2|x||y| xy < ...”
January 3, 2019
GMATGuruNY posted a reply to If the average of four numbers is 35, how many of the in the Data Sufficiency forum
“Sum of the 4 numbers = (quantity)(average) = 4*35 = 140. Statement 1: None of the numbers are exactly 3 To save time, check whether it''s possible to get different answers to the question stem while also satisfying Statement 2. Case 1: 0, 33, 33, 74 --> sum = 0+33+33+74 = 140 In this ...”
January 3, 2019
GMATGuruNY posted a reply to If a car traveled from Townsend to Smallville at an average in the Data Sufficiency forum
“Statement 1: The trip from Townsend to Smallville took 50% longer than the trip from Smallville to Townsend. Case 1: Distance between Townsend and Smallville = 80 miles Time to travel from Townsend to Smallville at a speed of 40 mph = 80/40 = 2 hours. Time to travel from Smallville to Townsend = ...”
January 3, 2019
GMATGuruNY posted a reply to On each lab that René completed he received either 100 in the Data Sufficiency forum
“Let x = the number of 100-point labs and y = the number of 85-point labs. Question stem, rephrased: What is the value of x? Statement 1: 100x + 85y = 1140 20x + 17y = 228 The value in blue implies the following: Since 20x will have a units digit of 0, 17y must have a UNITS DIGIT OF 8. ...”
January 3, 2019
GMATGuruNY posted a reply to Absolute value in the Problem Solving forum
“Alternate approach: Since an absolute value cannot be negative -- implying that the right side of the equation must be NONNEGATIVE -- we know that x≥0. If x²-6=x, we get: x²-x-6=0 (x-3)(x+2) = 0 Only the factor in green implies a nonnegative option for x: x-3=0 x=3. The correct ...”
January 3, 2019
GMATGuruNY posted a reply to What is the units digit of the number z? in the Data Sufficiency forum
“The usage of number implies that we should consider NON-INTEGER values. Both statements are satisfied by z=18.1 and z=19.1 Since the units digit of z can be different values, the two statements combinecd are INSUFFICIENT. The correct answer is E.”
January 2, 2019
GMATGuruNY posted a reply to Is √(x+1)^2=x+1 ? in the Data Sufficiency forum
“√(a²) = |a|. Question stem, rephrased: Is |x+1| = x+1? The answer will be YES if x+1 is NONNEGATIVE: x+1≥0 x≥-1. Question stem, rephrased again: Is x≥-1? Statement 1: x=0 or x=2. Since x≥-1 in both cases, the answer to the question stem is YES. SUFFICIENT. Statement 2: ...”
December 31, 2018
GMATGuruNY posted a reply to If f(x)=1-(1/x), then f(f(f(x)))=? in the Problem Solving forum
“Let x=2 and apply the function three times: f(2) = 1 - 1/2 = 1/2. f(1/2) = 1 - 1/(1/2) = -1. f(-1) = 1 - (1/-1) = 2. The correct answer must yield a value of 2 when x=2. Only A works. The correct answer is A.”
December 31, 2018
GMATGuruNY posted a reply to Singular or Plural Verb with None in the Sentence Correction forum
“Any BAG taken on the subway IS subject to search by the police. Any BAGS taken on the subway ARE subject to search by the police. In each of these sentences, any is a MODIFIER describing the subject in blue. In the first sentence, the verb (is) is SINGULAR to match the singular subject in blue. ...”
December 31, 2018
GMATGuruNY posted a reply to Brady, Charlie, and Daryl play on the same baseball team. Th in the Data Sufficiency forum
“Statement 1: No information about Charlie or Daryl. INSUFFICIENT. Statement 2: For every 2 home run hits made by Charlie and Daryl combined, Brady made 4 home run hits, implying that Brady made 4 of every 6 home run hits: 4/6 = 2/3. SUFFICIENT. The correct answer is B.”
December 31, 2018
GMATGuruNY posted a reply to Skier Lindsey Vonn completes a straight 300-meter downhill r in the Problem Solving forum
“Downhill speed - uphill speed = (x+10) - (x-8) = 18. Implication: The downhill speed is 18 mps greater than the uphill speed. We can PLUG IN THE ANSWERS, which represent the downhill speed. Since the downhill speed is 18 mps greater than the uphill speed, the correct answer must be GREATER ...”
December 31, 2018
GMATGuruNY posted a reply to Two dogsled teams raced across a 300 mile course in Wyoming. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent B''s speed. When the correct answer is plugged in, B''s time - A''s time = 3 hours. For each team: Time = distance/speed = 300/speed. B: B''s speed = 15 mph, implying that A''s speed = 15+5 = 20 mph In this case, B''s time - A''s time = 300/15 - ...”
December 30, 2018
GMATGuruNY posted a reply to In a stack of boards at a lumber yard, the 20th board counti in the Problem Solving forum
“1 2 3 4 5 6 7 8 9 10 11 12 13 14 15 16 17 18 19 = 16 20 = 15 14 13 12 11 10 9 8 7 6 5 4 3 2 1 In the rendering above: The red values represent the number of boards when counting from the TOP. The blue values represent the number of boards when counting from the ...”
December 30, 2018
GMATGuruNY posted a reply to If the original price of an item in a retail store is marked in the Data Sufficiency forum
“Let the original price = 100. Then the markup = (m/100)*100 = m. The resulting price = 100+m. The subsequent discount = d/100*(100+m) = d + md/100 Thus, the total percent change = percent increase - percent decrease = m - d - md/100. For the final price to be greater than the original price, ...”
December 30, 2018
GMATGuruNY posted a reply to Mark has fewer than 9 coins. Each coin is either a quarter in the Data Sufficiency forum
“Statement 1: To MINIMIZE the number of coins so that a sum of 170 cents is yielded by at most 8 coins, we must MAXIMIZE the number of quarters. Since 7*25 = 175 cents, the number of quarters must be less than 7. 170 cents will be yielded by 6 quarters (totaling 150 cents) and 2 dimes (totaling 20 ...”
December 28, 2018
GMATGuruNY posted a reply to Pumping alone at their respective constant rates, one inlet in the Problem Solving forum
“Let the tank = 36 gallons. Since the first pipe takes 3 hours to fill 1/2 the tank -- and (1/2)(36) = 18 gallons -- the rate for the first pipe = w/t =18/3 = 6 gallons per hour. Since the second pipe takes 6 hours to fill 2/3 of the tank -- and (2/3)(36) = 24 gallons -- the rate for the second ...”
December 27, 2018
GMATGuruNY posted a reply to Solution A is 20% salt and Solution B is 80% salt. If you in the Problem Solving forum
“Since the desired salt percentage -- 50% -- is HALFWAY between the salt percentages for A and B (20% and 80%), the resulting solution must contain equal amounts of A and B. The correct answer is C.”
December 27, 2018
GMATGuruNY posted a reply to If the ratio of the price of 1 kilogram Camembert cheese to in the Data Sufficiency forum
“What is the value of T-C? Statement 1: T:B = 4:5. To combine T:B = 4:5 and C:B = 5:8, the element common to both ratios -- B -- must be represented by the SAME VALUE in each: T:B = 4:5 = 32:40. C:B = 5:8 = 25:40. Combining the two ratios, we get: C:T:B = 25:32:40. Case 1: T=32 and C=25, ...”
December 26, 2018
GMATGuruNY posted a reply to In a village of 100 households, 75 least one DVD player, 80 in the Problem Solving forum
“Let D = DVD owners, C = cellphone owners, and M = MP3 owners. T = D + C + M - (DC + DM + CM) - 2(DCM). The big idea with overlapping group problems is to SUBTRACT THE OVERLAPS. When we add together everyone in D, everyone in C, and everyone in M: Those in exactly 2 of the groups (DC + DM + ...”
December 26, 2018
GMATGuruNY posted a reply to A certain punch contains grape juice, orange juice, and in the Problem Solving forum
“The sum of the parts of the ratio = 2+3+7 = 12. Thus -- of every 12 ounces -- 2 ounces are grape juice, 3 ounces are orange juice, and 7 ounces are pineapple juice. Since grape juice constitutes 2 of every 12 ounces, the amount of grape juice is equal to 2/12 of the total: (2/12)(156) = 2*13 = ...”
December 26, 2018
GMATGuruNY posted a reply to If x is a factor of positive integer y, then which of the fo in the Problem Solving forum
“Strategy: Try to show that four of the answer choices do NOT have to be positive. Case 1: x=1 and y=1 In this case, A, B and D are not positive. Eliminate A, B and D. Case 2: x=1 and y=2 In this case, C is not positive. Eliminate C. The correct answer is E.”
December 26, 2018
GMATGuruNY posted a reply to The sum of 4 different odd integers is 64. What is the value in the Data Sufficiency forum
“Statement 1: Since the numbers are EVENLY SPACED, median = sum/count: 64/4 = 16. Since the median = 16, the 4 odd integers must be as follows: 13, 15, 17, 19. Thus, the greatest of the 4 odd integers = 19. SUFFICENT. Statement 2: The 4 odd integers yielded by Statement 1 -- 13, 15, 17, 19 ...”
December 26, 2018
GMATGuruNY posted a reply to If x^2+y^2=28 and xy=11, what is the value of (x+y)^2? in the Problem Solving forum
“Every test-taker should know the following quadratic identities: (x+y)² = x² + y² + 2xy (x-y)² = x² + y² - 2xy (x+y)(x-y)² = x² - y² Substituting x²+y²=28 and xy=11 into (x+y)² = x² + y² + 2xy, we get: (x+y)² = 28 + 2*11 = 50. The correct answer is C. An alternate ...”
December 25, 2018
GMATGuruNY posted a reply to There are 10 books on a shelf: 5 English books, 3 Spanish bo in the Problem Solving forum
“P(2 different languages) = 1 - P(2 of the same language). Case 1: P(2 English books are selected) P(1st book is English) = 5/10. (Of the 10 books, 5 are English.) P(2nd book is English) = 4/9. (Of the 9 remaining books, 4 are English.) To combine these probabilities, we multiply: 5/10 * 4/9 = ...”
December 25, 2018
GMATGuruNY posted a reply to If the farmer sells 75 of his chickens, his stock of feed wi in the Problem Solving forum
“Total amount of feed = (number of chickens)(number of days). The number of chickens is INVERSELY PROPORTIONAL to the number of days. If the number of chickens DOUBLES, then the feed will last for 1/2 the number of days. If the number of chickens TRIPLES, then the feed will last for 1/3 the ...”
December 24, 2018
GMATGuruNY posted a reply to While driving on a highway, Harry and Ron crossed checkpoint in the Problem Solving forum
“9am-10am: Since Harry reaches checkpoint P at 9am -- and travels at rate of 30 mph -- from 9am to 10am Harry travels 30 miles beyond checkpoint P. Thus, when Ron reaches checkpoint P at 10am, he is 30 miles behind Harry. Checkpoint Q: When people compete, SUBTRACT THEIR RATES. Every hour Ron ...”
December 23, 2018
GMATGuruNY posted a reply to Work/Rate in the Data Sufficiency forum
“Let J = the number of hours that John works. Since John assembles 3 chairs per hour, the number of chairs assembled by John = 3J. Let L = the number of hours that Larry works. Since Larry assembles 4 chairs per hour, the number of chairs assembled by Larry = 4L. Since John and Larry work a total ...”
December 21, 2018
GMATGuruNY posted a reply to Five friends - Ross, Phoebe, Chandler, Joey and Monica - in the Problem Solving forum
“Number of options for Phoebe = 1. (Must be Margherita.) Number of options for Ross = 3. (Of the 4 remaining pizzas, any but Hawaiian.) Number of options for Chandler = 3. (Any of the 3 remaining pizzas.) Number of options for Joey = 2. (Either of the 2 remaining pizzas.) Number of options for ...”
December 21, 2018
GMATGuruNY posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom apart in the Problem Solving forum
“Let the monthly rent for a one-bedroom apartment = $2, implying that the monthly rent for a two-bedroom apartment = 2 + (50% of 2) = 2 + 1 = $3. Since the monthly rent for a one-bedroom apartment = $2, the total amount required to rent a one-bedroom apartment for 12 months = 2*12 = 24. If Alex ...”
December 20, 2018
GMATGuruNY posted a reply to absolute value in the Problem Solving forum
“The CRITICAL POINTS are where the expressions inside the absolute values are equal to 0. x+5 = 0 when x=-5. Substituting x=-5 into y = |x+5|-|x-5|, we get: y = |-5+5| - |-5-5| = 0-10 = -10. x-5 = 0 when x=5. Substituting x=5 into y = |x+5|-|x-5|, we get: y = |5+5| - |5-5| = 10-0 = ...”
December 19, 2018
GMATGuruNY posted a reply to One woman and one man can build a wall together in two hours in the Problem Solving forum
“One woman and one man can build a wall together in two hours, but the woman would need the help of two girls in order to complete the same job in the same amount of time. Since replacing 1 man with 2 girls does not change the amount of time required to complete the job, 1 man is the equivalent of 2 ...”
December 19, 2018
GMATGuruNY posted a reply to At garage sale, all of the prices of the items sold were in the Problem Solving forum
“Since the radio = 15th highest price, 14 prices are HIGHER: RADIO-----14 higher prices-----> Since the radio = the 20th lowest price, 19 prices are LOWER: <-----19 lower prices-----RADIO-----14 higher prices----> Total number of items = 19 + RADIO + 14 = 34. The correct answer is ...”
December 19, 2018
GMATGuruNY posted a reply to x and y are positive integers. Is y an even integer? in the Data Sufficiency forum
“The product of two consecutive integers is always EVEN: 1*2 = 2 2*3 = 6 3*4 = 12 Statement 1: y+2 = x² + x y+2 = x(x+1) y+2 = product of 2 consecutive integers y+2 = EVEN y = EVEN - 2 y = EVEN - EVEN y = EVEN SUFFICIENT. Statement 2: No information about y. INSUFFICIENT. The ...”
December 18, 2018
GMATGuruNY posted a reply to (0.0004)(0.000005)/200,000 is equal to which of the followin in the Problem Solving forum
“I believe that the answer choices should appear as shown below: The blue values below cancel out, leaving only the red values: (4 * 10¯⁴)(5 * 10¯⁶) / (20 * 10⁴) = 10¯¹⁰/10⁴ = 10¯¹⁴. The correct answer is B.”
December 18, 2018
GMATGuruNY posted a reply to Sanjana jogged uphill for a while at an average speed of 3 m in the Problem Solving forum
“This is a MIXTURE problem. Two speeds (3 mph and 8 mph) are combined to form a mixture with an average speed of 4 mph. To determine how much time must be spent at each speed, we can use ALLIGATION. Let U = the uphill speed and D = the downhill speed. Step 1: Plot the 3 speeds on a number ...”
December 18, 2018
GMATGuruNY posted a reply to If 2 and 17 are factors of positive integer n, then which of in the Problem Solving forum
“2 and 17 have no factors in common. Since n must be divisible by both 2 and 17 -- and 2*17 = 34 -- n must be a MULTIPLE OF 34. Thus, n must be divisible by I. Eliminate any answer choice that does not include I. Eliminate B and E. If n=34, then n is not divisible by II or III. Eliminate any ...”
December 17, 2018
GMATGuruNY posted a reply to Seven students are trying out for the school soccer team, on in the Problem Solving forum
“To keep track of the number of options for each position, draw a TREE. Start with the MOST RESTRICTED position, which is SWEEPER. If Sweeper = 3, then Goalie = 5. If Sweeper = 4, then Fullback = 2. Here''s the tree so far: http://s11.postimage.org/laxnlsbof/soccer_half_tree.jpg Now complete ...”
December 17, 2018
GMATGuruNY posted a reply to In a network of car dealerships, a group of d sales director in the Data Sufficiency forum
“A group...EACH has a team. The wording above does not convey a logical meaning. When each serves as an adverb, it cannot refer to a singular noun such as a group. When each serves as an adverb, it may refer only to a PLURAL noun. The prompt seems intended to convey the following: Since ...”
December 16, 2018
GMATGuruNY posted a reply to If one manual weighs 400 grams, how many kilograms does a in the Problem Solving forum
“48 manuals * (400 grams)/(1 manual) * (1 kilogram)/(1000 grams) = (48*400)/1000 = 192/10 = 19.2 kilograms.”
December 16, 2018
GMATGuruNY posted a reply to When the positive integer x is divided by 9, the remainder in the Problem Solving forum
“Let x=5, since dividing 5 by 9 yields a remainder of 5: 5/9 = 0 R5. When 3x=15 is divided by 9, we get: 15/9 = 1 R6. The correct answer is E.”
December 16, 2018
GMATGuruNY posted a reply to The main ingredient in a certain prescription drug capsule in the Problem Solving forum
“Each capsule contains 600 milligrams of ingredient. 10⁶ milligrams = 1 kilogram. 1 kilogram of ingredient = 500 dollars. To determine the cost per capsule, we must use the relationships above to convert 600 milligrams into dollars: (600 milligrams) * (1 kilogram)/(10⁶ milligrams) * (500 ...”
December 15, 2018
GMATGuruNY posted a reply to Each Machine of type A has 3 steel parts and 2 chrome parts. in the Problem Solving forum
“(3 steel parts in each type A machine) + (4 steel parts in each type B machine) = 20 steel parts: 3A + 4B = 20 3A = a multiple of 3 less than 20. Options for 3A: 3, 6, 9, 12, 15, 18 4B = a multiple of 4 less than 20. Options for 4B: 4, 8, 12, 16 Only the two values in blue yield a sum ...”
December 15, 2018
GMATGuruNY posted a reply to Did Jeff record more sales revenue this month than Dan did? in the Data Sufficiency forum
“Statement 1: For every $100 commission that Dan earns, Jeff earns $120 in commission. Since the commission rates for Dan and Jeff are unknown, no way to determine whether Jeff recorded more sales revenue than Dan. INSUFFICIENT. Statement 2: Since Jeff''s sales and Dan''s sales can be any ...”
December 14, 2018
GMATGuruNY posted a reply to If sets A and B have the same number of terms, is the standa in the Data Sufficiency forum
“Standard deviation describes how much the values in a set deviate from the mean. A larger standard deviation indicates that the values are deviating more -- getting farther away from -- the mean. So the question can be rephrased: Do the values in set A deviate more from the mean than the do ...”
December 14, 2018
GMATGuruNY posted a reply to Is (y−10)^2>(x+10)^2? ----Veritas in the Data Sufficiency forum
“x² < y² can be rephrased as follows: |x| < |y| Thus, the question stem can be rephrased as follows: Is |x+10| < |y-10|? |a-b| = the distance between a and b |a+b| = |a-(-b)| = the distance between a and -b Thus, the question stem can be further rephrased as follows: Is the ...”
December 14, 2018
GMATGuruNY posted a reply to Three congruent circles overlap in such a way that each circ in the Problem Solving forum
“The statement above is incorrect. https://i.postimg.cc/jL1NMjTL/three-congruent-circles-shaded-region.png The shaded region encompassing the equilateral triangle is not a circle.”
December 13, 2018
GMATGuruNY posted a reply to Three congruent circles overlap in such a way that each circ in the Problem Solving forum
“Area of an equilateral triangle = (s²/4)√3. √3 ≈ 1.7. https://i.postimg.cc/1gCbnSTK/three-congruent-circles.png Each circle has a radius of 8, yielding the equilateral triangle above. Area of the equilateral triangle = (8²/4)√3 = 16√3 ≈ (16)(1.7) = 27. The three circles form ...”
December 13, 2018
GMATGuruNY posted a reply to A baseball team’s season consists of playing 162 games. At in the Problem Solving forum
“The team has won 58 percent of the games it has played. 58% = 58/100 = 29/50. The fraction in blue implies that the number of wins must be a MULTIPLE OF 29: If 50 games are played, the number of wins = (29/50)(50) = 29. If 100 games are played, the number of wins = (29/50)(100) = 58. If 150 ...”
December 12, 2018
GMATGuruNY posted a reply to Effect of several Tsunamis in the Sentence Correction forum
“A method is a PROCEDURE for accomplishing a particular goal. Since the clause in red does not discuss a procedure, it cannot be summed up as a METHOD.”
December 11, 2018
GMATGuruNY posted a reply to Effect of several Tsunamis in the Sentence Correction forum
“The SC above is modeled -- not altogether successfully -- after SC30 in the OG12: https://www.beatthegmat.com/not-sure-about-the-answer-of-a-question-from-og12-t265701.html Rather than study the SC above, stick to the official SC.”
December 11, 2018
GMATGuruNY posted a reply to The table above shows the number of students in three clubs in the Problem Solving forum
“The values in the chart DOUBLE-COUNT any student who belongs to 2 of the 3 clubs. The totals for chess and drama -- 40 and 30 -- double-count the 10 students who belong to both chess AND drama. The totals for chess and math -- 40 and 25 -- double-count the 5 students who belong to both chess AND ...”
December 11, 2018
GMATGuruNY posted a reply to This year, a woman has a lucrative one-year position. During in the Problem Solving forum
“Let r=9, with the result that 1+r = 10. Her husband can turn each dollar she gives him into 1+r, which will be deposited in a bank account. Let the wife give the husband $1, implying that the husband turns this $1 into 1+r = $10. Thus, the amount deposited into the account = $10. The ...”
December 11, 2018
GMATGuruNY posted a reply to Line DB divides Rectangle ABCD into two equal triangles. Is in the Data Sufficiency forum
“Yes, the line will be a diagonal, but the four angles created by this diagonal will each be 45 degrees only if the rectangle is a square.”
December 10, 2018
GMATGuruNY posted a reply to What is the solution set of (1+|x|)(1+x) > 0? in the Problem Solving forum
“x=0 satisfies (1+|x|)(1+x) > 0. Since x=0 is not included in B, C, D or E, eliminate B, C, D and E. The correct answer is A.”
December 10, 2018
GMATGuruNY posted a reply to Tom drives from town A to town B, driving at a constant spee in the Problem Solving forum
“Let the distance between A and B = 120 miles. Since the 120-mile distance between A and B is twice the distance between B and C, the distance between B and C = 60 miles, implying that the total distance = 120+60 = 180 miles. Since the average speed for the 120-mile leg between A and B = 60 ...”
December 10, 2018
GMATGuruNY posted a reply to If the average (arithmetic mean) of five consecutive negativ in the Problem Solving forum
“The value of k is irrelevant. For any set of 5 consecutive integers, the difference between the greatest and least will always be 4. The correct answer is A.”
December 9, 2018
GMATGuruNY posted a reply to Three photographers, Lisa, Mike and Norm, take photos of a w in the Problem Solving forum
“The sum for Lisa and Mike is 50 less than the sum for Norm and Mike. Since Mike is common to both sums, the 50-photo difference must be yielded solely by Lisa and Norm. Implication: Lisa took 50 fewer photos than Norm. We can PLUG IN THE ANSWERS, which represent the number of photos taken ...”
December 9, 2018
GMATGuruNY posted a reply to Andrew sells vintage clothing at a flea market at which he in the Problem Solving forum
“Let h=3. Since an average of $78 is sold per hour, the total revenue for 3 hours = 3*78 = 234. Since the cost for the day is composed of $150 for the table rental and $10 per hour for the assistant, the cost for the day = 150 + 3*10 = 180. P = profit = revenue - cost = 234 - 180 = 54. The ...”
December 9, 2018
GMATGuruNY posted a reply to OG2019 -Logical flow in the Critical Reasoning forum
“It takes for granted that X implies that X is an ASSUMPTION: a statement that must be true for the conclusion to hold. Thus, when X is negated, the conclusion must be invalidated. B: It takes for granted that the volunteers with the highest levels of self-esteem had better social skills than did ...”
December 8, 2018
GMATGuruNY posted a reply to OG2019 -Logical flow in the Critical Reasoning forum
“Premise: Volunteers with the highest levels of self-esteem consistently rated themselves as having much better social skills than did the volunteers with moderate levels. Conclusion: Attaining an exceptionally high level of self-esteem greatly improves one’s social skills. The correct answer ...”
December 8, 2018
GMATGuruNY posted a reply to 2k years ago Frank was 3k years old. In k years Frank's age, in the Problem Solving forum
“Let k=10. 2k years ago Frank was 3k years old. Since k=10, 20 years ago Frank was 30 years old, implying that his age now = 30+20 = 50. In k years Frank''s age, in years, will be: Since Frank is now 50 years old, Frank''s age in 10 years = 50+10 = 60. The correct answer must yield a value ...”
December 7, 2018
GMATGuruNY posted a reply to Which of the following equations is satisfied by x=1+√2? in the Problem Solving forum
“Alternate approach: For any quadratic in the form x² + bx + c = 0, where b and c are rational numbers: If one of the roots is m+√n, then the other root is m-√n. Sum of the roots = -b Product of the roots = c Here, since one of the roots is 1+√2, the other root is 1-√2. Thus: -b ...”
December 7, 2018
GMATGuruNY posted a reply to Each day at Dan’s new job, he earns $10 more than the day in the Data Sufficiency forum
“Since each payday is $10 more than the preceding payday, the list of 15 paydays constitutes an EVENLY SPACED SET. Statement 1: For any evenly spaced set: Median = Sum/Quantity. Thus: Pay on the 14th day = median of the 3 most recent days = sum/quantity = 690/3 = 330. Since the pay on the ...”
December 6, 2018
GMATGuruNY posted a reply to Tom saved $10,000 at a constant compound interest rate of r in the Problem Solving forum
“Original deposit: 10,000. The balance doubles every 10 years. After 10 years, we get: 2*10,000 = 20,000. After 20 years, we get: 2*20,000 = 40,000. After 30 years, we get: 2*40,000 = 80,000. The correct answer is E.”
December 6, 2018
GMATGuruNY posted a reply to If a, b, and c are positive integers such that a < b < in the Data Sufficiency forum
“Does (a/100) * (b/100) * c = integer? Test integer values such that a < b < c. Statement 1: b = (a/100)¯¹ Thus, b = 100/a. Test the smallest possible value for a. Case 1: a=1 Here, b =100/1 = 100. In this case, (a/100) * (b/100) * c = 1/100 * 100/100 * c = c/100. If c ...”
December 5, 2018
GMATGuruNY posted a reply to If a, b, and c are positive integers, what is the remainder in the Data Sufficiency forum
“Statement 1: No information about b. INSUFFICIENT. Statement 2: No information about a. INSUFFICIENT. Statements combined: Case 1: c=3, with the result that a=3³=27 and that b=(3-2)³=1 In this case, a-b = 27-1 = 26. Dividing 26 by 6, we get: 26/6 = 4 R2 Case 2: c=4, with the ...”
December 5, 2018
GMATGuruNY posted a reply to If w, x, and y are consecutive odd positive integers and w & in the Problem Solving forum
“Test easy cases: 5-3-1 = 1 7-5-3 = -1 The case in green indicates that -1 is a possible value of y-x-w. The correct answer is C.”
December 5, 2018
GMATGuruNY posted a reply to x is a positive number. What is the median of x, √x and x^ in the Data Sufficiency forum
“To determine the median of x, √x and x², we need to know the value of x. Statement 1: Since x is positive, we can safely divide both sides by x: x²/x = x/x x = 1 SUFFICIENT. Statement 2: x² + x + 1 = 3x x² - 2x + 1 = 0 (x-1)² = 0 x = 1 SUFFICIENT. The correct answer is D.”
December 5, 2018
GMATGuruNY posted a reply to A triangle is formed by connecting three randomly chosen ver in the Problem Solving forum
“Let the 6 vertices = A, B, C, D, E and F. P(the triangle includes AT LEAST 1 side of the hexagon) = 1 - P(the triangle includes NO sides of the hexagon). From the 6 vertices, the number of ways to choose 3 to form a triangle = 6C3 = (6*5*4)/(3*2*1) = 20. Of these 20 triangles, only 2 include ...”
December 5, 2018
GMATGuruNY posted a reply to Working together, Machine A and Machine B can produce a in the Data Sufficiency forum
“Since A+B take 4 hours to produce 200 widgets, the combined rate for A+B = w/t = 200/4 = 50 widgets per hour. To determine A''s time to produce 200 widgets, we need to know A''s rate. Question stem, rephrased: What is A''s rate? Statement 1: Since B takes 5 hours to produce 50 widgets, B''s ...”
December 4, 2018
GMATGuruNY posted a reply to How many positive two-digit integers have a remainder of 1 w in the Problem Solving forum
“A quick lesson on remainders: Onto the problem at hand: a remainder of 1 when divided by 2 x = 2a + 1 = 1, 3, 5, 7... In other words, x must be ODD. a remainder of 4 when divided by 5 x = 5b + 4 = 4, 9, 14, 19... Since x must be odd, we get: x = 9, 19, 29.... a remainder of ...”
December 4, 2018
GMATGuruNY posted a reply to If there are 4 pairs of twins, and a committee will be in the Problem Solving forum
“Number of options for the 1st person = 8. Number of options for the 2nd person = 6. (Of the 7 people left, we can''t use the twin of the 1st person chosen, leaving 7-1= 6 choices.) Number of options for the 3rd person = 4. (Of the 6 people left, we can''t use the twins of the 2 people already ...”
December 3, 2018
GMATGuruNY posted a reply to For each of her sales, a saleswoman receives a commission in the Problem Solving forum
“The first $500 of the $800 sale earns 20% commission, while the remaining $300 earns 30%. Average commission percentage per $800 = (500*20 + 300*30)/800 = (5*20 + 3*30)/8 = 190/8 = 23.75 ≈ 24. The correct answer is B.”
December 1, 2018
GMATGuruNY posted a reply to When a certain tree was first planted, it was 4 feet tall in the Problem Solving forum
“Let x = the yearly increase. Height after 4 years = 4 + 4x. Height after 6 years = 4 + 6x. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. The phrase in red implies the following: The height in the 6th year was 6/5 of the height in the 4th ...”
December 1, 2018
GMATGuruNY posted a reply to If k is a positive integer and n=(k-1)k(k+1), is n a multipl in the Data Sufficiency forum
“Every other even integer is a MULTIPLE OF 4: 2, 4, 6, 8, 10, 12... Thus, the product of two consecutive even integers = product of a multiple of 4 and an even non-multiple of 4 = MULTIPLE OF 8: 2*4 = 8 4*6 = 2*2*2*3 = 8*3 10*12 = 2*5*2*2*3 = 8*15 Statement 1: Since k is odd, k-1 and k+1 ...”
November 30, 2018
GMATGuruNY posted a reply to If x^2=x+1, then x^4=? in the Problem Solving forum
“Squaring both sides, we get: (x²)² + (x+1)² x⁴ = x² + 2x + 1 Substituting x²=x+1 into x⁴ = x² + 2x + 1, we get: x⁴ = (x+1) + 2x + 1 x⁴ = 3x + 2 The correct answer is A.”
November 30, 2018
GMATGuruNY posted a reply to Is the positive integer p a multiple of 50? in the Data Sufficiency forum
“Any integer that is a multiple 10 is also a multiple of 5. Implication: Any integer that satisfies Statement 1 will also satisfy Statement 2. Both statements are satisfied by the following cases: Case 1: p=10, which is a multiple of 10 (and thus is also a multiple of 5) In this case, p is NOT a ...”
November 30, 2018
GMATGuruNY posted a reply to The point A, B, C, and D are on the number line, not in the Data Sufficiency forum
“The drawings below satisfy both statements: http://s4.postimage.org/1yjxdhskk/ABCD_number_line.jpg Since in the first case BD=1 and in the second case BD=17, the two statements combined are insufficient. The correct answer is E.”
November 30, 2018
GMATGuruNY posted a reply to In a business school case competition, the top three teams in the Problem Solving forum
“Case 1: Team A wins a prize, with the result that Team B must win a prize Number of prizes that could be won by A = 3. Number of remaining prizes that could be won by B = 2. Number of teams that could win the third prize = 4. (Any of the 4 remaining teams.) To combine these options, we ...”
November 30, 2018
GMATGuruNY posted a reply to The juice stall at the circus stocked just 2 brands of in the Problem Solving forum
“Let n=50, implying that 50% of the sold juice packs are A, while the other half are B. In other words, the store sells an EQUAL NUMBER of each type of juice pack. Let the store sell 2 OF EACH TYPE of juice pack. Revenue from two $1 packs of A = 2*1 = 2. Revenue from two $1.5 packs of B = ...”
November 29, 2018
GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum
“Let James'' rate = 3 mph. James started from his home and drove eastwards at a constant speed. Exactly 90 minutes after James stated from his home, his brother Patrick started from the same point and drove in the same direction as James did at a different constant speed. Patrick overtook James ...”
November 29, 2018
GMATGuruNY posted a reply to The equation of a circle in the x-y coordinate plane is x^2 in the Problem Solving forum
“The equation for a circle with its center at the origin and a radius of r is as follows: x² + y² = r². Thus, x² + y² = 25 is a circle with its center at the origin and a radius of 5. A point on this circle will have integer coordinates in three cases: Case 1: The radius is horizontal ...”
November 29, 2018
GMATGuruNY posted a reply to On a partly cloudy day, Derek decides to walk back from work in the Problem Solving forum
“The average speed -- 2.8 miles per hour -- must be BETWEEN the two individual rates (s and s+1). Thus, s = 2 miles per hour and s+1 = 3 miles per hour. We can PLUG IN THE ANSWERS, which represent the fraction traveled at 2 miles per hour. When the correct fraction is plugged in, the average ...”
November 28, 2018
GMATGuruNY posted a reply to Eight consecutive integers are selected from the integers 1 in the Data Sufficiency forum
“When consecutive positive integers are divided by positive integer x, the resulting remainders also are consecutive: If x=4: 16/4 = 4 R0. 17/4 = 4 R1. 18/4 = 4 R2. 19/4 = 4 R3. 20/4 = 5 R0. From here, the cycle of remainders will repeat: 0,1,2,3,0,1,2,3... The smallest remainder is 0. The ...”
November 28, 2018
GMATGuruNY posted a reply to A club has 10 members. One president and two vice-presidents in the Problem Solving forum
“Number of options for president = 10. (Any of the 10 members.) From the remaining 9 members, the number of ways to choose 2 to serve as vice-president = 9C2 = (9*8)/(2*1) = 36. To combine these options, we multiply: 10*36 = 360. The correct answer is E.”
November 28, 2018
GMATGuruNY posted a reply to Twelve identical machines, running continuously at the same in the Problem Solving forum
“One approach is to use the following equation: (machines)(time) / output = (machines)(time) / output In the equation above: Machines and time are INVERSELY PROPORTIONAL. As the number of machines increases, the amount of time required to produce the same output decreases. Machines and ...”
November 24, 2018
GMATGuruNY posted a reply to In a plane, there are two parallel lines. One line has 5 in the Problem Solving forum
“One approach: Good Cases = Total Cases - Bad Cases. Total Cases: From 9 points, the number of ways to choose 3 = 9C3 = (9*8*7)/(3*2*1) = 84. Bad Case 1: Choosing 3 collinear points from the 5-point line, with the result that a triangle cannot be formed From the 5 points on this line, the ...”
November 24, 2018
GMATGuruNY posted a reply to Find x^4 + 1/x^4 if x – 1/x = 2. in the Problem Solving forum
“(x – 1/x)² = 2² x² + 1/x² - 2(x)(1/x) = 4 x² + 1/x² - 2 = 4 x² + 1/x² = 6 (x² + 1/x²)² = 6² x⁴ + 1/x⁴ + (2)(x²)(1/x²) = 36 x⁴ + 1/x⁴ + 2 = 36 x⁴ + 1/x⁴ = 34. The correct answer is D.”
November 23, 2018
GMATGuruNY posted a reply to If n is an integer greater than 1, what is the value of n? in the Data Sufficiency forum
“Since the prompt indicates that n is an integer greater than 1, the case in red is not possible. The only value that satisfies Statement 2 is n=2, making Statement 2 SUFFICIENT. The correct answer thus is not C but B.”
November 23, 2018
GMATGuruNY posted a reply to What is the sum of the prime factors of 2^8-1? in the Problem Solving forum
“Alternate approach: 2⁸ - 1 = 256 - 1 = 255 = 5*51 = 5*3*17. Sum of the prime factors = 5+3+17 = 25. The correct answer is E.”
November 22, 2018
GMATGuruNY posted a reply to June 25, 1982, fell on a Friday. On which day of the week in the Problem Solving forum
“Between 1982 and 1987 are 4 non-leap years and 1 leap year. Each non-leap year is composed of 365 days; a leap year is composed of 366 days. Thus, from June 25, 1982 to June 25, 1987, the total number of days = 4(365) + 366. Since June 25, 1982 is a Friday, every passing of 7 days will yield ...”
November 22, 2018
GMATGuruNY posted a reply to A man walking at a constant rate of 4 miles per hour is pass in the Problem Solving forum
“(man''s rate)/(woman''s rate) = (4 mph)/(20 mph) = 1/5. Between the moment when the woman passes the man and the moment when she stops to wait, the woman and the man each travel for 5 minutes. During these 5 minutes, the woman travels x miles. Since the man''s rate is 1/5 the woman''s rate, the ...”
November 21, 2018