GMATGuruNY posted a reply to W, X, Y and Z each represent a different number. If the sum in the Problem Solving forum
“Sum of all 4 rows = 3 + 6 + 9 + 0 = 18. Sum of all 4 columns = -2 + 7 + n + 5 = n + 10. The values in blue must be EQUAL, since each represents the sum of all 16 values in the table. Thus: n+10 = 18 n=8. The correct answer is C.”
Today
GMATGuruNY posted a reply to How many 3 digit numbers can we make such that two of the in the Problem Solving forum
“Number of digit options for the repeated digit = 9. (Any digit but 0.) Number of digit options for the non-repeated digit = 8. (Any digit but 0 and the digit already used.) Number of position options for the non-repeated digit = 3. (The hundreds place, the tens place, or the units place.) To ...”
Today
GMATGuruNY posted a reply to Is 10m > 5n - k? in the Data Sufficiency forum
“Statement 1: n=2m Substituting n=2m into 10m > 5n-k, we get: 10m > 5(2m) - k ? 10m > 10m - k ? 0 > -k ? k > 0 ? No way to determine whether k>0. INSUFFICIENT. Statement 2: |k| = -k This equation is valid only if k≤0. No information about m or n. INSUFFICIENT. ...”
Yesterday
GMATGuruNY posted a reply to Machine A and Machine B can produce 1 widget in 3 hours work in the Problem Solving forum
“Algebra: Machine A and Machine B can produce 1 widget in 3 hours working together at their respective constant rates. (A+B)(3) = 1 widget. If Machine A''s speed were doubled, the two machines could produce 1 widget in 2 hours working together at their respective rates. (2A+B)(2) = 1 widget. ...”
Yesterday
GMATGuruNY posted a reply to Machine A and Machine B can produce 1 widget in 3 hours work in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent A''s time to produce 1 widget. Since A and B working together take 3 hours to produce 1 widget, A working alone must take MORE than 3 hours. Eliminate A, B and C. Let the value of each widget = 30 units. Since A and B together take 3 hours to produce ...”
Yesterday
GMATGuruNY posted a reply to In an office that employs 120 people, m% of the employees in the Data Sufficiency forum
“Use a DOUBLE-MATRIX to organize the data. Statements combined: Case 1: m=25% and c=25% Total number of males = (25/100)(120) = 30. Total number of custodial employees = (25/100)(120) = 30. The following matrix is yielded: https://i.postimg.cc/H88Lq5zN/matrix_custodial_1.png In this case, ...”
September 22, 2018
GMATGuruNY posted a reply to In these difficult economic times, those who have---Veriats in the Sentence Correction forum
“The default referent for a subject pronoun is the subject of the preceding INDEPENDENT CLAUSE. A: Those who have public pensions are being pursued strongly by pension advance companies that operate without much oversight from banking regulators, but they are now drawing scrutiny. Here, the default ...”
September 21, 2018
GMATGuruNY posted a reply to GMATPREP Question - what is the subject in the Sentence Correction forum
“This interpretation is not valid. The comparative in blue is clearly an ADJECTIVE describing a city.. Since as big as refers not to China but to A CITY. no comparison between China and Singapore is implied. The sentence unambiguously compares A CITY to Singapore, as discussed below. ...”
September 21, 2018
GMATGuruNY posted a reply to If m > 0, y > 0, and x is m percent of 2y, then, in te in the Problem Solving forum
“Let y=100, implying that 2y = 200. Let m=100. x is m percent of 2y. Since m=100 and 2y=200, x = 100% of 200 = 200. m is what percent of x? m/x = 100/200 = 1/2 = 50%. This is our target. Now plug y=100 into the answers to see which yields the target value of 50. Only E works: 5000/y = ...”
September 21, 2018
GMATGuruNY posted a reply to If 7 < m < 11 and −2 < n < 5, then which of th in the Problem Solving forum
“To determine the lower limit and the upper limit of mn, calculate mn using every combination of endpoints (7 and 11 for m, -2 and 5 for n): mn = (7)(-2) = -14. mn = (7)(5) = 35. mn = (11)(-2) = -22. mn = (11)(5) = 55. The LOWER limit is the LEAST of the results above: -22. The UPPER ...”
September 21, 2018
GMATGuruNY posted a reply to The square ACEG shown below has an area of 36 units squared. in the Problem Solving forum
“Almost no math is needed here. Answer choice A implies the following: BCD is a 45-45-90 triangle in which each leg has a length of 1. DEF is a 45-45-90 triangle in which each leg has a length of 5. Answer choice E implies the following: BCD is a 45-45-90 triangle in which each leg has a ...”
September 20, 2018
GMATGuruNY posted a reply to If Albert can travel 200 miles in 4 hours, how many hours in the Problem Solving forum
“Since Albert travels 200 miles in 4 hours, his rate = 200/4 = 50 mph. When the correct answer is divided into 350 miles, the resulting rate must be 50 mph. Only C works: 350/7 = 50. The correct answer is C.”
September 20, 2018
GMATGuruNY posted a reply to In four years, Andy will be twice as old as Betsy. How old in the Data Sufficiency forum
“In four years, Andy will be twice as old as Betsy. Since Andy''s age in 4 years is twice Betsy''s age in 4 years, we get: A+4 = 2(B+4) A+4 = 2B+8 A-2B = 4. Statement 1: Since Andy''s age 4 years ago is twice Betsy''s current age, we get: A-4 = 2B A-2B = 4. Same equation as given in the ...”
September 20, 2018
GMATGuruNY posted a reply to How many multiples of 33 lie between 101 and 1,000, inclusiv in the Problem Solving forum
“Since 1000 - 101 ≈ 900 -- and the answer choices are a bit spread out -- we can count the multiples of 33 simply by dividing 33 into 900: 900/33 = 300/11 = a bit more than 27. Thus, there are 27 multiples of 33 between 101 and 1000. The correct answer is B.”
September 20, 2018
GMATGuruNY posted a reply to Comparison - GMAT paper test in the Sentence Correction forum
“OA: A neutron star, as small as 12 miles in diameter but containing half as much matter as the Sun, has a gravitational force at its surface about 67 billion times greater than that on Earth. The green portion conveys the following meaning: The words in brackets are omitted so that the green ...”
September 19, 2018
GMATGuruNY posted a reply to Rasheed bought two kinds of candy bars, chocolate and toffee in the Data Sufficiency forum
“I believe that the problem has been transcribed incorrectly. Statement 1 should indicate that Rasheed bought not 2 fewer packages but only 1 fewer package, as shown in the following screen shot: https://i.postimg.cc/t7bcm77Z/rasheed_Gprep-ds-2.jpg If we know the number of chocolate BARS that ...”
September 19, 2018
GMATGuruNY posted a reply to √3-2|+|3-√2|+|5+√3|+|1-√2|=? in the Problem Solving forum
“|a-b| = the distance between a and b. |a+b| = |a-(-b| = the distance between a and -b. |√3-2| + |3-√2| + |5+√3| + |1-√2| = |5+√3| + |√3-2| + |1-√2| + |3-√2| = |√3+5| + |√3-2| + |1-√2| + |3-√2| = |√3-(-5)| + |√3-2| + |1-√2| + |3-√2| The red terms ...”
September 19, 2018
GMATGuruNY posted a reply to On the number line shown, the distance between 0 and a, a in the Problem Solving forum
“In the number line shown, the distance between 0 and a, a and b, and a and c is in the ratio of 1:2:3. To determine the ratio of a to b to c, TEST AN EASY CASE. Let a=1. Since a is ONE PLACE to the right of 0, b must be TWO PLACES to the right of a (implying that b=3), while c must be THREE ...”
September 18, 2018
GMATGuruNY posted a reply to If 12 men and 16 women can do a piece of work in 5 days and in the Problem Solving forum
“Let M = the rate for each man and W = the rate for each woman. The TIME RATIO for 12 men and 16 women to 13 men and 24 women is 5 days to 4 days. Since time and rate are RECIPROCALS, the RATE RATIO for 12M+16W and 13M+24W is equal to the reciprocal of the time ratio: (12M+16W)/(13M+24W) = ...”
September 18, 2018
GMATGuruNY posted a reply to A certain investment grows at an annual interest rate of 8%, in the Problem Solving forum
“When a value increases repeatedly by r%: Final amount = Original amount * (1 + r/100)^number of changes. Let original amount = 1. Since the original amount increases by a factor of 16: Final amount = 16. Since the investment increases by 2% every quarter: r = 2. Since x = the number of ...”
September 18, 2018
GMATGuruNY posted a reply to Grandmother's Punch hangover cure is a mix of two in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the amount of cider. When the correct answer is plugged in, the amount of alcohol in the 750 ml bottle = 87 ml. Since the alcohol percentage in the cider = 5% = 1/20, the correct answer is almost certain to be a multiple of 20. Of the five answer ...”
September 17, 2018
GMATGuruNY posted a reply to A tank has 5 inlet pipes. Three pipes are narrow and two are in the Problem Solving forum
“Let the rate of each wide pipe = 2 liters per hour. Combined rate for 2 wide pipes = 2*2 = 4 liters per hour. Since each narrow pipe works at 1/2 the rate of each wide pipe, the rate of each narrow pipe = (1/2)(2) = 1 liter per hour. Combined rate for 3 narrow pipes and 2 wide pipes = (3*1) + ...”
September 16, 2018
GMATGuruNY posted a reply to Gunther, the pizza delivery boy, went out from the store in the Problem Solving forum
“Average = sum/quantity. In this case: Average speed = (sum of the minutes spent at each speed)/(total number of minutes). Total time spent at 15mph = 30 minutes. Total time spent delivering pizzas at 0mph = 30 minutes. Total time spent at 30mph = 15 minutes. Average speed = (15*30 + 0*30 + ...”
September 15, 2018
GMATGuruNY posted a reply to A basket contains 5 apples, of which 1 is spoiled and the in the Problem Solving forum
“P(spoiled apple is selected) = 1 - P(spoiled apple is NOT selected). P(1st apple is not spoiled) = 4/5. (Of the 5 apples, 4 are not spoiled). P(2nd apple is not spoiled) = 3/4. (Of the 4 remaining apples, 3 are not spoiled). Since we want both events to happen, we multiply the fractions: ...”
September 15, 2018
GMATGuruNY posted a reply to Point P is the point of the circle x^2 + y^2 -2x -4y = 4 wit in the Problem Solving forum
“(x-h)² + (y-k)² = r² is a circle with a center at (h, k) and a radius of r. x² + y² - 2x - 4y = 4 x² - 2x + y² - 4y = 4 x² - 2x + 1 + y² - 4y + 4 = 4 + 1 + 4 (x-1)² + (y-2)² = 9 (x-1)² + (y-2)² = 3³ The equation above constitutes a circle with a center at (1, 2) and a ...”
September 14, 2018
GMATGuruNY posted a reply to At what speed was Erik running when he was at the halfway in the Data Sufficiency forum
“Statements combined: Each statement conveys the same information: that the average speed for the whole trip was 5 miles per hour. The AVERAGE speed for the whole trip does not constrain the speed AT THE HALWAY POINT. At the halfway point, the speed could be ANY NONNEGATIVE VALUE. Thus, the ...”
September 13, 2018
GMATGuruNY posted a reply to (1^2+2^2+3^3+…+20^2) / (1+2+3+ …+20)=? in the Problem Solving forum
“The answer choices represent the ratio between the numerator and the denominator of the given expression. Option A implies that the numerator is about 14 times the denominator Option B implies that the numerator is less than 7 times the denominator. Option C implies that the numerator is 41 times ...”
September 13, 2018
GMATGuruNY posted a reply to (1^2+2^2+3^3+…+20^2) / (1+2+3+ …+20)=? in the Problem Solving forum
“Since the answer choices are very spread out, we can BALLPARK -- and we can be somewhat lax with our estimations. Numerator: If the 11 greatest terms were 10²=100, the sum of the 11 greatest terms = 11*100 = 1100. If the 11 greatest terms were 20²=400, the sum of the 11 greatest terms = ...”
September 13, 2018
GMATGuruNY posted a reply to If the interior angles of a triangle are in the ratio 3 to in the Problem Solving forum
“The sum of the 3 angles of a triangle = 180. The sum of the parts of the ratio = 3+4+5 = 12. Since 180/12 = 15, the multiplier for the ratio is 15, implying that the largest angle = 5*15 = 75. The correct answer is D.”
September 12, 2018
GMATGuruNY posted a reply to During a one day sale, a store sold each sweater of a in the Data Sufficiency forum
“Statement 1: Case 1: 1 sweater is sold for $270 Case 2: 3 sweaters are sold for $90 each Since the number of sweaters sold can be different values, INSUFFICIENT. Statement 2: Since the $30 markup is 1/2 the cost of each sweater, the cost of each sweater = 60. Thus, the selling price of ...”
September 12, 2018
GMATGuruNY posted a reply to Three boys are ages 4, 6 and 7 respectively. Three girls are in the Problem Solving forum
“Since only a few cases are possible, we can list them out: 4+6+5+8 = 23 4+6+5+9 = 24 4+6+8+9 = 27 4+7+5+8 = 24 4+7+5+9 = 25 4+7+8+9 = 28 6+7+5+8 = 26 6+7+5+9 = 27 6+7+8+9 = 30 Of the 9 cases above, the four in red are ODD, implying that the remaining five cases are EVEN. Since 5/9 of ...”
September 12, 2018
GMATGuruNY posted a reply to The perimeter of a rectangular garden is 360 ft. What is the in the Data Sufficiency forum
“The GRE is administered by ETS, which also used to administer the GMAT. The GRE Quantitative Guide states that any side of a triangle or parallelogram can be used as a base. The GMAT is likely to abide by this definition. But the terms length and long seem to connote a different meaning when ...”
September 11, 2018
GMATGuruNY posted a reply to The perimeter of a rectangular garden is 360 ft. What is the in the Data Sufficiency forum
“Definitions of length: Merriam-Webster: The LONGER OR LONGEST dimension of an object. American Heritage: The measurement of something along its GREATEST dimension.”
September 11, 2018
GMATGuruNY posted a reply to a family has 5 children, what is the probability that there in the Problem Solving forum
“The problem should make clear that P(boy) = P(girl) = 1/2: P(exactly n times) = P(one way) * total possible ways. Let B = boy and G = girl. P(one way): One way to get exactly 3 boys and 2 girls is BBBGG. P(BBBGG) = 1/2 * 1/2 * 1/2 * 1/2 * 1/2 = 1/32. Total possible ways: Any ...”
September 11, 2018
GMATGuruNY posted a reply to The sum of the ages of Doris and Fred is y years. If Doris in the Problem Solving forum
“Since Doris is 12 years older than Fred, let Fred = 2 and Doris = 2+12 = 14. y = sum of their ages = 2+14 = 16. Since Fred = 2 and y=16, Fred''s age y years from now = 2+16 = 18. This is our target. Now plug y=16 into the answers to see which yields the target value of 18. Only D works: 3y/2 - ...”
September 11, 2018
GMATGuruNY posted a reply to The rate of a certain chemical reaction is directly in the Problem Solving forum
“The trick is translate the chemical relationship into the following equation: R = A²/B Here''s why the equation above works: 1)The problem states that R is directly proportional to A². Directly proportional means that as one value increases, the other value also increases by a ...”
September 10, 2018
GMATGuruNY posted a reply to In a certain pond, 50 fish were caught, tagged, and returned in the Problem Solving forum
“Of the 50 fish caught in the second catch, 2 were tagged: 2/50 = 4/100 = 4%. Since the percent of tagged fish in the second catch approximates the percent of tagged fish in the pond, the total number of tagged fish -- 50 -- must be equal to about 4% of the total number of fish in the pond: 50 = ...”
September 10, 2018
GMATGuruNY posted a reply to If 5^{m-2}2^{m+2} is an n-digit integer, where m is an inte in the Problem Solving forum
“Since m=2 will yield an integer value for the given expression and will make the math easier, ignore the condition that m>2 and let m=2. Plugging m=2 into 5^(m-2) * 2^(m+2), we get: 5⁰2⁴ = 1*16 = 16. Since the result is a 2-digit integer, n=2. The correct answer must work for n=m=2. Only ...”
September 10, 2018
GMATGuruNY posted a reply to Sam's car was fined when he gave Joe and Peter a ride, so in the Problem Solving forum
“Thanks for the heads up. I''ve revised my post accordingly.”
September 9, 2018
GMATGuruNY posted a reply to What is the probability of n(n+1)(n+2) being evenly divisibl in the Data Sufficiency forum
“Statement 1: Since n is an integer, n(n+1)(n+2) = the product of 3 consecutive integers. WRITE IT OUT and LOOK FOR A PATTERN. 1*2*3 2*3*4 3*4*5 4*5*6 5*6*7 6*7*8 7*8*9 8*9*10 9*10*11 10*11*12 11*12*13 12*13*14 13*14*15 14*15*16 15*16*17 16*17*18 Each of the products in red ...”
September 9, 2018
GMATGuruNY posted a reply to Twenty-four men can complete a work in sixteen days.Thirty in the Problem Solving forum
“Let the rate for each man = 1 widget per day, implying that the rate for 24 men = 24 widgets per day. Since 24 men complete the job in 16 days, the total amount of work = rt = 24*16 widgets. Since 32 women require 24 days, the rate for 32 women = w/t = (24*16)/24 = 16 widgets per day. Since ...”
September 9, 2018
GMATGuruNY posted a reply to Sam's car was fined when he gave Joe and Peter a ride, so in the Problem Solving forum
“Given that the answers choices are integers, I believe that the following reflects the problem''s intent: The three fractions in the prompt -- 1/4, 1/3 and 1/2 -- imply that the fine must be divisible by 4, 3 and 2. Smallest possible case: Total fine = 4*3*2 = 24. Since Sam paid $4 less ...”
September 9, 2018
GMATGuruNY posted a reply to GMATPREP Question - what is the subject in the Sentence Correction forum
“Option B for SC18 in the OG12: Plants are more efficient at acquiring carbon than fungi. Logical interpretation 1: Plants are more efficient at acquiring carbon than Logical interpretation 2: Plants are more efficient at acquiring carbon than fungi Since B allows for more than one logical ...”
September 8, 2018
GMATGuruNY posted a reply to The bear alarm at Grizzly's Peak ski resort sounds an in the Problem Solving forum
“The alarm sounds for 3 of EVERY 4 BEARS that actually appear, If 4 bears appear, then the number of alarms = 3. Since the alarm sounds only 3 times for 4 bears, 1 of these 4 bears is undetected. Since there are 10 false alarms for every 1 undetected bear, the number of false alarms = 10. Thus, ...”
September 7, 2018
GMATGuruNY posted a reply to If a mixture of ground meat consists of 2 pounds of veal in the Problem Solving forum
“The answer choices represent the price per pound: (total cost)/(total number of pounds). Since 7 pounds are purchased, the correct answer must have a denominator of 7. A, C and D lack denominators and thus can be eliminated. Since the denominator in B does not have to be 7, eliminate B. The ...”
September 7, 2018
GMATGuruNY posted a reply to How many hours did it take Dale to drive from A-town to B-to in the Data Sufficiency forum
“Statement 1: Time and rate have a RECIPROCAL relationship. 3 TIMES AS FAST implies 1/3 THE TIME. Thus, the 2 hours that would be spent traveling 3 times as fast must be equal to 1/3 the actual time: 2 = (1/3)t t = 6 hours. SUFFICIENT. Statement 2: Here, the time can be any nonnegative ...”
September 7, 2018
GMATGuruNY posted a reply to A palindrome is a number that reads the same forward and in the Problem Solving forum
“Number of options for the units digit = 5. (1, 3, 5, 7, or 9.) Number of options for the thousands digit = 1. (Must be the same as the units digit.) Number of options for the hundreds digit = 10. (Any of the digits 0-9.) Number of options for the tens digit = 1. (Must be the same as the hundreds ...”
September 7, 2018
GMATGuruNY posted a reply to Last year the price per share of Stock X increased by k in the Problem Solving forum
“Original ratio: Let the original price = 1 and the original earnings = 1. Resulting ratio: price/earnings = 1/1 = 1. New ratio: Let k=200 and m=100. Since the price increases by k=200%, the new price = 1 + (200/100)(1) = 3. Since the earnings increase by m=100%, the new earnings = ...”
September 6, 2018
GMATGuruNY posted a reply to What is the sum of roots of the equation x^2 – 40x + 399 = in the Problem Solving forum
“For any quadratic in the form x² + bx + c = 0: Sum of the roots = -b. Product of the roots = c. In the given quadratic, b = -40. Thus, the sum of the roots = -b = -(-40) = 40. The correct answer is D.”
September 6, 2018
GMATGuruNY posted a reply to If 3x + 2y = -2z, what is x? in the Data Sufficiency forum
“Prompt: 3x + 2y + 2z = 0 Statement 1: Multiplying by 2, we get: 2x - 2y - 2z = 20 Adding together 3x+2y+2z=0 and 2x-2y-2z=20, we get: (3x+2y+2z) + (2x-2y-2z) = 0 + 20 5x=20 x=4. SUFFICIENT. Statement 2: Multiplying by 2, we get: 2x + 2y + 2z = -4 Subtracting 2x+2y+2z = -4 from ...”
September 6, 2018
GMATGuruNY posted a reply to A and B can complete a task in 20 days. B and C can complete in the Problem Solving forum
“Alternate approach: Let the job = 240 units. Since A+B take 20 days to complete the 240-unit job, A+B = 240/20 = 12 units per day. Since B+C take 30 days to complete the 240-unit job, B+C = 240/30 = 8 units per day. Since A+C take 40 days to complete the 240-unit job, A+C = 240/40 = 6 units ...”
September 6, 2018
GMATGuruNY posted a reply to If r is a positive integer, n=r^3 and 4,14, and 27 are facto in the Problem Solving forum
“Since 4, 14 and 27 are all factors of n, the prime-factorization of n must include 2*2, 2*7 and 3*3*3. n = r³ implies that n is a perfect cube. The prime-factorization of a perfect cube must include at least 3 of each prime factor. Thus, the prime-factorization of n must include at least three ...”
September 5, 2018
GMATGuruNY posted a reply to If x and y are integers, what is the least possible positive in the Problem Solving forum
“Make a list of integer options for |21x| and |35y|: |21x| = 0, 21, 42, 63, 84, 105... |35y| = 0, 35, 70, 105... The smallest positive sum is yielded in the following cases: 21x = 42 and 35y = -35, with the result that 21x + 35y = 42 - 35 = 7 21x = -63 and 35y = 70, with the result that 21x + ...”
September 4, 2018
GMATGuruNY posted a reply to absolute value in the Data Sufficiency forum
“if a < y < z < b , is |y-a| less than |y-b| ? 1) |z-a| < |z-b| 2) |y-a| < |z-b| |a-b| = the distance between a and b. Since a < y < z < b, we get the following number line: a..........y..........z..........b Statement 1: |z-a| < |z-b| Since the distance ...”
September 4, 2018
GMATGuruNY posted a reply to Triathlete Dan runs along a 2-mile stretch of river and then in the Problem Solving forum
“When the same distance is traveled at two different speeds, the average speed will be the same for ANY DISTANCE. Thus, we can solve the problem above using a distance that is divisible by the two speeds. Let the distance in each direction = 30 miles. Time to run 30 miles at a rate of 10 miles per ...”
September 4, 2018
GMATGuruNY posted a reply to permutation/combination in the Problem Solving forum
“Mr. Smith shook hands with 3 times as many men as women. The phrase in blue implies that the number of men who shook hands with Mr. Smith is a MULTIPLE OF 3. Thus, the total number of men = (multiple of 3) + (Mr. Smith). In math terms: Number of men = 3a + 1, where a is a positive integer. ...”
September 4, 2018
GMATGuruNY posted a reply to GMATPREP Question - what is the subject in the Sentence Correction forum
“A comparison is questionable if it allows for more than one logical interpretation. Case 2 is not a logical interpretation of your revision of E. No reader will construe that what MANAGERS find is being compared to what A GRASPING finds. Since only Case 1 constitutes a logical interpretation, the ...”
September 4, 2018
GMATGuruNY posted a reply to At a certain hospital, 75% of the interns receive fewer than in the Problem Solving forum
“We can use a double-matrix: https://preview.ibb.co/iUwRPe/matrix_interns.png In the resulting matrix, total not tired = 19/100 = 19%. The correct answer is C.”
September 4, 2018
GMATGuruNY posted a reply to Points (x,y) in the rectangular coordinate plane in the Problem Solving forum
“Since the graph intercepts the x-axis to the left of the y-axis and has only one solution, its graph is as follows: y = (x-k)², where k<0. The equation above has an x-intercept at (k, 0), as shown in the figure above. The answer choices represent the sum of k (the x-intercept) and p (the ...”
September 4, 2018
GMATGuruNY posted a reply to Six children — A, B, C, D, E, and F — are going to sit i in the Problem Solving forum
“Alternate approach: Number of options for A = 6. (Any of the 6 chairs.) Number of options for B = 5. (Any of the 5 remaining chairs.) Number of options for C = 4. (Any of the 4 remaining chairs.) Number of options for D = 3. (Any of the 3 remaining chairs.) Number of options for E and F = 1. ...”
September 3, 2018
GMATGuruNY posted a reply to Is |xy|>x^2y^2 in the Data Sufficiency forum
“Looks good!”
September 2, 2018
GMATGuruNY posted a reply to 3 machines have a productivity ratio of 1 to 2 to 5. All 3 in the Problem Solving forum
“Let the rate for the fastest machine = 5 units per hour and the rate for the slowest machine = 1 unit per hour. Since the fastest machine works at a rate of 5 units per hour for all 9 hours, the work produced by the fastest machine = rt = 5*9 = 45 units. Since the slowest machine works at a rate ...”
September 2, 2018
GMATGuruNY posted a reply to Is x an integer? in the Data Sufficiency forum
“Statement 1: x/2 = 1, 2, 3, 4, 5... Multiplying every value by 2, we get: x = 2, 4, 6, 8, 10... In every case, x is an integer. SUFFICIENT. Statement 2: 2x = 1, 2, 3, 4, 5... Dividing every value by 2, we get: x = 1/2, 1, 3/2, 2, 5/2... If x=1/2, then x is not an integer. If x=1, then x ...”
September 2, 2018
GMATGuruNY posted a reply to integers in the Problem Solving forum
“If we use 0 as a placeholder -- so that 007 represents 7, 072 represents 72, etc. -- then we need to count the number of times that 7 will appear among the 3-digit integers from 000 to 999, inclusive. Total number of 3-digit integers from 000 to 999, inclusive = biggest - smallest + 1 = ...”
September 1, 2018
GMATGuruNY posted a reply to If x^2/9 – 4/y^2 = 12, what is the value of x? in the Data Sufficiency forum
“x²/9 – 4/y² = 12 (x/3)² - (2/y)² = 12 The resulting equation is the DIFFERENCE OF TWO SQUARES: a² - b² = (a+b)(a-b). Thus, the equation can be rephrased as follows: (x/3 + 2/y)(x/3 - 2/y) = 12. Statement 1: Substituting x/3 + 2/y = 6 into (x/3 + 2/y)(x/3 - 2/y) = 12, we get: ...”
September 1, 2018
GMATGuruNY posted a reply to Agatha Christie´s Escalator in the Problem Solving forum
“Algebraic approach: Let P = Poirot''s rate, M = Marple''s rate, and E = the escalator''s rate. Since P travels 3 steps for every 2 steps that M travels: P/M = 3/2. Ratios can be MULTIPLIED: P/E * E/M = P/M . Since P/M = 3/2, we get: P/E * E/M = 3/2 Let x = the number of steps on ...”
August 30, 2018
GMATGuruNY posted a reply to Agatha Christie´s Escalator in the Problem Solving forum
“Let P = Poirot''s rate, M = Marple''s rate, and E = the escalator''s rate. Since P travels 3 steps for every 2 steps that M travels: P/M = 3/2. Ratios can be MULTIPLIED: P/E * E/M = P/M Since P/M = 3/2, we get: P/E * E/M = 3/2. We can PLUG IN THE ANSWERS, which represent the number of ...”
August 30, 2018
GMATGuruNY posted a reply to If 4 is one solution of the equation x^2 + 3x + k = 10, in the Problem Solving forum
“Alternate approach: x² + 3x = 10-k x² + 3x = constant. Since x=4 and the correct answer choice are both roots, they must yield the same result when plugged into x² + 3x. Plugging x=4 into x² + 3x, we get: 4² + 3*4 = 28. If we test the answer choices, only x=-7 yields the same result ...”
August 30, 2018
GMATGuruNY posted a reply to A jar contains 16 red balls and 8 white balls. If 3 balls ar in the Problem Solving forum
“P(1st marble is white) = 8/24. (Of the 24 marbles, 8 are white.) P(2nd marble is white) = 7/23. (Of the 23 remaining marbles, 7 are white.) P(3rd marble is white) = 6/22. (Of the 22 remaining marbles, 6 are white.) To combine these probabilities, we multiply: 8/24 * 7/23 * 6/22 = 1/3 * 7/23 * ...”
August 30, 2018
GMATGuruNY posted a reply to In a certain summer school program, there are five periods in the Problem Solving forum
“Alternate approach: Since Science class must be followed immediately by Science lab, Science class cannot be taken during the last period. Thus: Number of options for Science class = 4. (Any of the first 4 periods.) Number of options for Science lab = 1. (Must be the period immediately after ...”
August 30, 2018
GMATGuruNY posted a reply to What is the value of j + k? in the Data Sufficiency forum
“Statement 1: Case 1: m=0, j=0, k=0 In this case, j+k = 0+0 = 0 Case 2: m=0, j=0, k=1 In this case, j+k = 0+1 = 1 Since j+k can be different values, INSUFFICIENT. Statement 2: Dividing both sides of the equation by 5, we get: j+k = 2. SUFFICIENT. The correct answer is B.”
August 30, 2018
GMATGuruNY posted a reply to Angela has 15 pairs of matched socks. If she loses 7 in the Problem Solving forum
“15 matched pairs = 30 socks. E: 12 If Angela has 12 matched pairs left -- for a total of 24 socks -- then the number of socks lost = 30-24 = 6. Not viable, since Angela must lose 7 socks. The correct answer is E.”
August 30, 2018
GMATGuruNY posted a reply to To fill a number of vacancies, an employer must hire 3 in the Problem Solving forum
“Number of ways to choose 3 programmers from 6 applicants = 6C3 = (6*5*4)/(3*2*1) = 20. Number of ways to choose 2 managers from 4 applicants = 4C2 = (4*3)/(2*1) = 6. To combine the options above, we multiply: 20*6 = 120. The correct answer is C.”
August 29, 2018
GMATGuruNY posted a reply to What is the units digit of (3^{101})(7^{103})? in the Problem Solving forum
“When an integer is raised to consecutive powers, the resulting units digits repeat in a CYCLE. 3¹⁰¹: 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 ...”
August 29, 2018
GMATGuruNY posted a reply to It takes the high-speed train x hours to travel the z miles in the Problem Solving forum
“Plug in easy numbers for the two rates. Then plug in a distance that is a multiple of both the two individual rates and the COMBINED rate. Let the high speed rate = 3 miles per hour. Let the regular rate = 2 miles per hour. Combined rate for the trains = 2+3 = 5 miles per hour. Let z = ...”
August 28, 2018
GMATGuruNY posted a reply to The world wildlife fund has declared that global warming in the Sentence Correction forum
“a phenomenon that is caused by human beings. Here, the that-clause in green serves to modify a phenomenon. Question: What KIND of phenomenon? Answer: A phenomenon THAT IS CAUSED BY HUMAN BEINGS. Most scientists agree that the statement above is true. To convey this meaning, we insert most ...”
August 28, 2018
GMATGuruNY posted a reply to November is traditionally the strongest - OG 2018 in the Sentence Correction forum
“Incorrect: When compared with most sport utility vehicles, minivans get better gas mileage. Here, the usage of when compared is unwarranted and conveys a nonsensical meaning, implying that minivans GET better mileage at the same time as they are COMPARED. The following is sufficient to convey the ...”
August 28, 2018
GMATGuruNY posted a reply to How many different positive integers having six digits are in the Problem Solving forum
“How many ways can the letters BBBGG be arranged? Number of ways to arrange 5 elements = 5!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of identical elements can be ARRANGED. The reason: When the identical elements swap positions, the ...”
August 28, 2018
GMATGuruNY posted a reply to A certain IT department of fewer than 15 people hires coders in the Data Sufficiency forum
“Let c = coders and s = system administrators. Statement 1: 55,000(c-2) + 45,000(s+2) = 535,000 55(c-2) + 45(s+2) = 535 11(c-2) + 9(s+2) = 107. Implication of the resulting equation: (multiple of 11) + (multiple of 9) = 107. (multiple of 9) = 107 - (multiple of 11). Subtract ...”
August 28, 2018
GMATGuruNY posted a reply to Justin, Max, and Paul each have a collection of marbles. in the Problem Solving forum
“Since Max has 30% more than Paul''s 80 marbles, Max = 80 + (3/10)(80) = 104. Since Justin has 50% fewer than Max''s 104 marbles, Justin = (1/2)(104) = 52. The correct answer is C.”
August 28, 2018
GMATGuruNY posted a reply to How many different positive integers having six digits are in the Problem Solving forum
“There are 6 positions in the integer. The two 4''s must occupy a pair of positions. From the 6 positions, the number of ways to choose a pair for the two 4''s = 6C2 = (6*5)/(2*1) = 15. The remaining 4 positions must be occupied by 3, 5, 7 or 8, 7 or 8. Number of options for the 3 = 4. (Any ...”
August 28, 2018
GMATGuruNY posted a reply to George bought a large electronic item with a 15% off coupon, in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the original price of the item. When the correct answer is plugged in, George reimburses the store $40.50. Since the coupon discount = 15% = 15/100 = 3/20, the original price of the item is almost certainly a multiple of 20. Of the 5 answer choices, ...”
August 27, 2018
GMATGuruNY posted a reply to Exactly 8 years ago, Jim's son was twice as old as Jim's in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the daughter''s current age. When the correct answer is plugged in, the nd the dau B: 10, implying that the daughter''s age 8 years ago = 10-8 = 2 Since the son 8 years ago was twice as old as the daughter, the son''s age 8 years ago = 2*2 = 4, ...”
August 27, 2018
GMATGuruNY posted a reply to If m and r are two numbers on a number line, what is the in the Data Sufficiency forum
“Translate the words into math. The DISTANCE between x and 0 is |x|. HALFWAY between two numbers is the AVERAGE of the two numbers. Statement 1: The distance between r and 0 is 3 times the distance between m and 0. |r| = 3|m| r = 3m or r=-3m. No way to solve for r. INSUFFICIENT. ...”
August 27, 2018
GMATGuruNY posted a reply to If a, b, and c are positive integers, what is the remainder in the Data Sufficiency forum
“Clearly, neither statement is sufficient on its own. Statements combined: The statements indicate that a and b are CONSECUTIVE PERFECT CUBES. Make a list of perfect cubes: 1, 8, 27, 64, 125... Calculating the difference between one perfect cube and the next, we get: 8-1 = 7 27-8 = 19 ...”
August 27, 2018
GMATGuruNY posted a reply to GMAT Prep Problem 1 in the Problem Solving forum
“Let the amount saved each month = $1. Total saved for the entire year = 12*1 = $12. Since the total saved for the entire year -- $12 -- is 3 times the total not saved each month, the total not saved each month = 12/3 = $4. Thus, the total monthly pay = (total saved each month) + (total not saved ...”
August 27, 2018
GMATGuruNY posted a reply to GMAT Prep Problem 3 in the Problem Solving forum
“The prompt requires the following: (greatest integer)(next largest integer) < 200. The answer choices imply that the greatest integer must be 13, 14, 15, or 20 15² = 225 and 20² = 400. Implication: (15)(next largest integer) and (20)(next largest integer) will each yield a product greater ...”
August 27, 2018
GMATGuruNY posted a reply to Solution X, which is 50% alcohol, is combined with solution in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the amount of Y. Since the percentage for the mixture (35%) is closer to Y''s percentage (30%) than to X''s percentage (50%), Y must constitute MORE THAN 1/2 of the 16-liter mixture. Thus, the amount of Y must be equal to more than 8 liters. Eliminate ...”
August 27, 2018
GMATGuruNY posted a reply to Each of the cucumbers in 100 pounds is composed of 99% water in the Problem Solving forum
“Since the cucumbers are 99% water, the 100 pounds of cucumbers are composed of 99 pounds of water and 1 POUND OF OTHER STUFF. After evaporation makes the cucumbers 98% water, the 1 POUND OF OTHER STUFF must constitute 2% of the new total: 1 = (2/100)x x = 100/2 = 50. The correct answer ...”
August 26, 2018
GMATGuruNY posted a reply to Of the 9,000 people who voted in a recent election, how many in the Data Sufficiency forum
“Statement 1: (women for X) : (women against X) = 2:1. Of every 3 women voters, 2 voted for X, while 1 voted against X. In other words, 2/3 of women voters voted for X. No way to determine the NUMBER of women who voted for X. INSUFFICIENT. Statement 2: No info about women voters. ...”
August 26, 2018
GMATGuruNY posted a reply to The sum of positive integers x and y is 77, what is the in the Data Sufficiency forum
“Statement 1: Substituting x=y+1 into x+y = 77, we get: (y+1) + y = 77 2y = 76 y = 38, implying that x = 38+1 = 39. Thus, xy = 39*38. SUFFICIENT. Statement 2: For x and y to have the same tens digit and a sum of 77, they must be equal to the pair of values yielded by Statement 1: 38 and ...”
August 26, 2018
GMATGuruNY posted a reply to If n = 10^10 and n^n = 10^d, what is the value of d? A. 10^ in the Problem Solving forum
“Substituting n= 10¹⁰ into n^n = 10^d, we get: (10¹⁰ )^(10¹⁰)= 10^d When an exponent is raised to a power, we MULTIPLY the exponents. Multiplying the exponents in blue, we get: 10^(10*10¹⁰) = 10^d 10^(10¹¹) = 10^d Since each side has the same base, the exponent in blue must be ...”
August 26, 2018
GMATGuruNY posted a reply to How many five-digit numbers can be formed from the digits in the Problem Solving forum
“For the 5-digit integer to be a multiple of 4, the last two digits must form a multiple of 4. Options: 04, 12, 20, 24, 32, 40, 52. Case 1: Last 2 digits include 0 Number options for the last 2 digits = 3. (04, 20 or 40.) Number of options for the ten-thousands place = 4. (Any of the 4 ...”
August 25, 2018
GMATGuruNY posted a reply to Michael drives x miles due north at arrives at Point A. He in the Problem Solving forum
“In deference to Brent''s concerns, the problem should read as follows: x miles north, y miles east, and z miles in a straight line back to x constitute a right triangle with legs x and y and hypotenuse z. The only right triangle in which all 3 sides are integers and the shortest leg is 5 is ...”
August 24, 2018
GMATGuruNY posted a reply to The average (arithmetic mean) of the five numbers in a data in the Problem Solving forum
“Sum = (quantity)(average). The average (arithmetic mean) of the five numbers in a data set is 72. Sum = 5*72 = integer with a UNITS DIGIT OF 0. The average (arithmetic mean) of the first three numbers is 98. Sum = 3*98 = integer with a UNITS DIGIT OF 4. For the sum of all 5 numbers to ...”
August 24, 2018
GMATGuruNY posted a reply to Linda and Angela contract to paint a neighbor's house. Even in the Problem Solving forum
“Let the pay rate = $1 per hour. Let Angela''s time = 4 hours. Since Linda works 50% longer, Linda''s time = 4 + (1/2)4 = 6 hours. Since a total of 10 hours are worked at a rate of $1 per hour, the total pay = 10*1 = $10. Since each worker receives m dollars of the total pay, m=$5. Since ...”
August 23, 2018
GMATGuruNY posted a reply to United Telephone charges a base rate of $10.00 for service, in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS. When the correct answer is plugged in, the two companies will charge the same amount. B: 10 minutes Since United charges $10 plus $0.25 per minute, the charge from United = 10 + 10(0.25) = $12.50. Since Atlantic charges $12 plus $0.20 per ...”
August 23, 2018
GMATGuruNY posted a reply to A whole number greater than 1 has remainders of 1 when it is in the Problem Solving forum
“We can PLUG IN THE ANSWERS. To yield a remainder of 1 when divided by 4, the correct answer must be 1 more than a multiple of 4. The smallest answer choice that is 1 more than a multiple of 4 is 61. When 61 is divided by 2, 3 or 5, the remainder is 1 in each case. The correct answer is C.”
August 23, 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 ...”
August 23, 2018
GMATGuruNY posted a reply to What is the decimal equivalent of (1/5)^5? in the Problem Solving forum
“1/5⁵ = = (1/25)(1/25)(1/5) = (4/4 * 1/25)(4/4 * 1/25)(2/2 * 1/5) = (4/100)(4/100)(2/10) = 32/100000 = 32 * 10ˉ⁵ = 0.00032 The correct answer is A.”
August 22, 2018
GMATGuruNY posted a reply to While it costs about the same in the Sentence Correction forum
“Correct! OA: The cost of running nuclear power plants is about the same as is the cost] for other types of power plants. The blue verb in brackets is omitted but implied.”
August 22, 2018
GMATGuruNY posted a reply to Five friends Alastair, Bell, Cook, Darren and Eoin appeared in the Problem Solving forum
“To determine the ratio of the scores, plug in numbers and reduce the resulting ratio as much as possible. Let A = Alastair, B = Bell, C = Cook, D = Darren, and E = Eoin. Let B = the product of the denominators = 2*5*5*2 = 100. Darren’s score was 3/2 times that of Bell’s score. D = 3/2(B) = ...”
August 22, 2018
GMATGuruNY posted a reply to While it costs about the same in the Sentence Correction forum
“The OA implies the following: The cost of running nuclear power plants is about the same as for other types of power plants. The prepositions phrase in blue serves the same function as the prepositional phrase in red: both serve to modify the cost.”
August 21, 2018
GMATGuruNY posted a reply to While it costs about the same in the Sentence Correction forum
“to run for X implies that X is a GOAL. Mary plans to run for president. Conveyed meaning: The office of president = Mary''s goal. Thus, to run for other types of power plants implies that OTHER TYPES OF POWER PLANTS constitute a goal. Not the intended meaning. No one is attempting to reach ...”
August 21, 2018
GMATGuruNY posted a reply to While it costs about the same in the Sentence Correction forum
“OA: The cost of running nuclear power plants is about the same as for other types of power plants. Since the blue portion provides its own referent (other types of power plants), the referent in the red portion (nuclear power plants) is not implied in the blue portion. C: It costs about the ...”
August 21, 2018
GMATGuruNY posted a reply to If x and y are prime numbers, how many factors has x^2y^2? in the Data Sufficiency forum
“To count the positive factors of a positive integer: 1. Prime-factorize the integer 2. Write the prime-factorization in the form (a^p)(b^q)(c^r)... 3. The number of factors = (p+1)(q+1)(r+1)... Generally, GMAT problems about factors are constrained to POSITIVE factors. On the GMAT, the posted ...”
August 21, 2018
GMATGuruNY posted a reply to One machine, working at a constant rate, can fill a certain in the Problem Solving forum
“Time and rate have a RECIPROCAL RELATIONSHIP. If Mary works TWICE as fast as John, Mary''s time will be 1/2 John''s time. If Mary works THREE TIMES as fast as John, Mary''s time will be 1/3 John''s time Since 4 machines will work 4 times as fast as 1 machine, the time for 4 machines will ...”
August 21, 2018
GMATGuruNY posted a reply to Which of the following is the best approximation for 11^11-9 in the Problem Solving forum
“Another approach: 10¹¹ (100,000,000,000) is 100 TIMES the value of 10⁹ (1,000,000,000). Implication: 11¹¹ must be MORE THAN 100 TIMES the value of 9⁹. Since 9⁹ is so small when compared to 11¹¹, we can ignore the value of 9⁹ when we approximate: 11¹¹ - 9⁹ ≈ 11¹¹ The ...”
August 21, 2018
GMATGuruNY posted a reply to Which of the following is the best approximation for 11^11-9 in the Problem Solving forum
“Since the answer choices are very spread out, our approximation does not have to very exact. 11¹¹−9⁹ = 11¹¹− (11−2)⁹ ≈ 11¹¹ − 11⁹ = 11⁹(11²−1) ≈ (11⁹)(11²) = 11¹¹ The correct answer is D.”
August 21, 2018
GMATGuruNY posted a reply to Of 30 applicants for a job, 14 had at least 4 years' in the Problem Solving forum
“One approach is to use the following equation: Total = Group 1 + Group 2 - Both + Neither The big idea is to SUBTRACT THE OVERLAP. In the problem above, there is an overlap between the applicants with at least 4 years'' experience and the applicants with degrees. Some applicants belong to BOTH ...”
August 21, 2018
GMATGuruNY posted a reply to Which of the following points could lie in the same quadrant in the Problem Solving forum
“Every answer choice includes at least one negative sign. Test coordinate pairs that include at least one negative value. Case 1: a=1 and b=-1, so that (a, b) = (1, -1) Plug a=1 and b=-1 into the answer choices to see whether one of the answer choices yields a point in the same quadrant as ...”
August 21, 2018
GMATGuruNY posted a reply to If a and b are positive integers and x = 4^a and y = 9^b, in the Problem Solving forum
“x is equal to a POWER OF 4: 4, 16, 64... y is equal to a POWER OF 9: 9, 81... If x=4 and y=81, then xy = 324, which has a units digit of 4. The correct answer is B.”
August 21, 2018
GMATGuruNY posted a reply to Is z an even integer? in the Data Sufficiency forum
“Statement 1: Make a list of options for z/2: z/2 = 0, 2, 4, 6, 8... To get a list of options for z, multiply every value by 2: z = 0, 4, 8, 12, 16... In every case, z is an even integer, so the answer to the question stem is YES. SUFFICIENT. Statement 2: Make a list of options for 3z: 3z ...”
August 21, 2018
GMATGuruNY posted a reply to Set S consists of all prime integers less than 10 in the Problem Solving forum
“It is not possible for the two products -- that of the two chosen numbers and that of the two unchosen numbers -- to be equal. Each of the two products has the same probability of being greater. Thus, the probability that the product of the two chosen numbers is greater = 1/2. The correct ...”
August 20, 2018
GMATGuruNY posted a reply to How many days after the purchase of product X does its in the Data Sufficiency forum
“Statement 1: Minimum number of days: purchase date = January 31, expiration date = March 1 Here, the expiration date = (28 days of February) + (first day of March) = 29 days after purchase. Maximum number of days: purchase date = January 1, expiration date = March 31 Here, the expiration date ...”
August 19, 2018
GMATGuruNY posted a reply to Collectively, the five children in the Kramer family have 30 in the Problem Solving forum
“In ascending order, let the 5 trophy values be a, b, c, d and e. To maximize the value of d -- the second highest value -- we must MINIMIZE the values of a, b and c. Since every child must have a different number of trophies, the least possible values for a, b and c are a=1, b=2, and c=3. Since ...”
August 18, 2018
GMATGuruNY posted a reply to Mona and Donald fly to Rome for the weekend. They take cash in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total number of notes. The number of €10 notes they take is double the number of $10 notes they take. Thus, the ratio of €10 notes to $10 notes = 2:1. Since the sum of the parts of this ratio = 2+1 = 3, the total number of notes must be a ...”
August 18, 2018
GMATGuruNY posted a reply to A certain junior class has 1,000 students and a certain in the Problem Solving forum
“P(sibling pair) = (total number of sibling pairs)/(total number of possible pairs). Total number of possible pairs: There are 1000 juniors and 800 seniors. Total number of ways to combine 1 junior with 1 senior = 1000*800 = 800,000. Total number of sibling pairs = 60. Thus: ...”
August 17, 2018
GMATGuruNY posted a reply to Jason can stack two shelves in 3 hours and Maria can stack in the Problem Solving forum
“Let each shelf = 6 pounds. Since Jason takes 3 hours to stack 2 6-pound shelves -- for a total of 12 pounds -- Jason''s rate = 12/3 = 4 pounds per hour. Since Maria takes 2 hours to stack 3 6-pound shelves -- for a total of 18 pounds -- Maria''s rate = 18/2 = 9 pounds per hour. Total weight of 13 ...”
August 16, 2018
GMATGuruNY posted a reply to GPREP 3 SC-9 in the Sentence Correction forum
“Fixed! Thanks for catching the typo.”
August 16, 2018
GMATGuruNY posted a reply to Is n an integer less than 5? in the Data Sufficiency forum
“Statement 1: Make a list of options for 5n: 5n = 1, 2, 3, 4, 5... To get a list options for n, divide every value above by 5: n = 1/5, 2/5, 3/5, 4/5, 1... If n = 1/5, the answer to the question stem is NO. If n = 1, the answer to the question stem is YES. INSUFFICIENT. Statement 2: Make a ...”
August 16, 2018
GMATGuruNY posted a reply to A company hired a printer to produce a total of x + 1 in the Problem Solving forum
“The company requested 3 more 2¢ envelopes than 5¢ envelopes. Let the number of 5¢ envelopes = 2, and the number of number of 2¢ envelopes = 2+3 = 5, with the result that the cost of the envelopes = (5*2) + .(2*5) = 20 cents. A company hired a printer to produce a total of x + 1 envelopes. ...”
August 16, 2018
GMATGuruNY posted a reply to A librarian has a set of ten books, including four different in the Problem Solving forum
“Since the 4 Lincoln books must be side-by-side, place them in a BLOCK: C.”
August 16, 2018
GMATGuruNY posted a reply to A vending machine randomly dispenses four different types in the Problem Solving forum
“There are twice as many strawberry candies as grape candies. If G=1, then S=2. There are twice as many apple candies as strawberry candies. If S=2, then A=4. There are twice as many apple candies as orange candies. If A=4, then O=2. Resulting ratio: G:S:A:O = 1:2:4:2. Since the sum of the ...”
August 16, 2018
GMATGuruNY posted a reply to Three copying machines A, B, and C, working together at in the Problem Solving forum
“Let the job = 8 pages. Since A+B+C take 2 hours to copy the 8-page job, the combined rate for A+B+C = 8/2 = 4 pages per hour. Since B+C take 4 hours to copy the 8-page job, the combined rate for B+C = 8/4 = 2 pages per hour. A''s rate = (rate for A+B+C) - (rate for B+C) = 4-2 = 2 pages per ...”
August 15, 2018
GMATGuruNY posted a reply to (x – 1)(y – 1) = 1? in the Data Sufficiency forum
“Alternate approach: Statement 1: Case 1: x=2 Substituting x=2 into x+y = xy, we get: 2 + y = 2y 2 = y. In this case, (x-1)(y-1) = (2-1)(2-1) = 1, so the answer to the question stem is YES. Case 2: x=3 Substituting x=3 into x+y = xy, we get: 3+ y = 3y 3 = 2y 3/2 = y. In this case, ...”
August 15, 2018
GMATGuruNY posted a reply to Students are in clubs as follows: Science-20, Drama-30, and in the Problem Solving forum
“When we count the total in Science, the total in Drama, and the total in Band, any students in exactly two of the clubs are counted TWICE. Thus, we must SUBTRACT these students so that they are not double counted: Total = Science + Drama + Band - (exactly 2 clubs) = 20 + 30 + 12 - (8+6+4) = 44. ...”
August 15, 2018
GMATGuruNY posted a reply to Uncle Bruce is baking chocolate chip cookies. He has 36 in the Problem Solving forum
“= Since chocolate must constitute 20% of the cookies, the 36 ounces of dough must constitute the remaining 80%: 36 = 0.8x x = 36/0.8 = 360/8 = 45 ounces. Since the cookies = 45 ounces, and the dough = 36 ounces, the amount of chocolate used = 45-36 = 9 ounces. Thus -- of the 15 ounces of ...”
August 15, 2018
GMATGuruNY posted a reply to Three printing presses, R, S, and T, working together at the in the Problem Solving forum
“Let the job = 20 pages. Since R+S+T take 4 hours to print the 20-page job, the combined rate for R+S+T = 20/4 = 5 pages per hour. Since S+T take 5 hours to print the 20-page job, the combined rate for S+T = 20/5 = 4 pages per hour. R''s rate = (rate for R+S+T) - (rate for S+T) = 5-4 = 1 page per ...”
August 14, 2018
GMATGuruNY posted a reply to If a number between 0 and 1 is selected at random, which of in the Problem Solving forum
“Put the ranges over the same DENOMINATOR: A: 0 and 3/20 B. 30/20 and 1/5 -- 3/20 and 4/20 C. 1/5 and 1/4 --> 4/20 and 5/20 D. 1/4 and 3/10 --> 5/20 and 6/20 E. 3/10 and 1/2 --> 6/20 and 10/20 Since the greatest range is offered by E (10/20 - 6/20 = 4/20), the number is most likely ...”
August 14, 2018
GMATGuruNY posted a reply to Lyme disease is caused by a bacterium transmitted to humans in the Critical Reasoning forum
“E, rephrased as a basic statement: The other species on which deer tick larvae feed harbor other bacteria that ticks transmit to humans. The conclusion is constrained to the number of ticks infected with the bacterium that causes LYME DISEASE. Information about other bacteria is irrelevant ...”
August 14, 2018
GMATGuruNY posted a reply to Ben is driving on the highway at x miles per hour. (One mile in the Problem Solving forum
“Note: One revolution = one CIRCUMFERENCE. Let x = 2 miles per hour, implying that the distance traveled in 1 hour = 2*5280 = 10560 feet. Let y = 10 feet. Since the total distance traveled in 1 hour = 10560 feet, and each circumference = 10 feet, the number of revolutions in 1 hour = 10560/10 = ...”
August 14, 2018
GMATGuruNY posted a reply to Bob invests 100 dollars in a fund that yileds 15% simple in the Problem Solving forum
“Alternate approach: To earn exactly $100 in interest at rate of $15 earned each month, the number of months required = 100/15 = 20/3 = 6.66 months. The smallest integer greater than 6.66 is 7. Implication: After 7 months, the total amount of interest will for the first time EXCEED $100, with ...”
August 14, 2018
GMATGuruNY posted a reply to When x is divided by 2, the remainder is 1 and y is divided in the Problem Solving forum
“Algebraic approach: When x is divided by 2, the remainder is 1. In other words, x is a multiple of 2 plus 1: x = 2a + 1. When y is divided by 8, the remainder is 2. In other words, y is a multiple of 8 plus 2: y = 8b + 2. Thus: 2x + y = 2(2a+1) + (8b + 2) = 4a + 2 + 8b + 2 = 4a + 8b + ...”
August 14, 2018
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 ...”
August 14, 2018
GMATGuruNY posted a reply to If the average of 993, 994, 996, 997, 998, 1001, 1001, 1002, in the Problem Solving forum
“Sum of the 10 terms = (quantity)(average) = 10*999 = 9990. If we add the units digits of the nine given terms, we get: 3+4+6+7+8+1+1+2+4 = 36. The sum of the nine given terms has a units digit of 6. The sum of all ten terms has a units digit of 0. Since (units digit of 6) + (units digit of 4) = ...”
August 12, 2018
GMATGuruNY posted a reply to Are all of the terms in Set A equal? in the Data Sufficiency forum
“I posted a solution to a very similar problem here: https://www.beatthegmat.com/from-og-12-t73239.html”
August 12, 2018
GMATGuruNY posted a reply to profit and loss in the Problem Solving forum
“Let r=0, implying that no profit is made and that the oranges are sold at cost. Let q=12, implying that the cost for 12 oranges is $12, with the result that the cost per orange = $1. 1.66 dozen = (5/3)(12) = 20 oranges. Since the cost for 20 oranges = $20, p=20. Thus: 5pq - 12r = (5*20*12) - ...”
August 11, 2018
GMATGuruNY posted a reply to In each game of a certain tournament, a contestant either in the Data Sufficiency forum
“Here is an algebraic way to combine the two statements: Let G = a game that results in a 2-point gain and L = a game that results in a 3-point loss. Statement 1: Since the played games yield a total of 4 points beyond the intital 100 points, we get: 2G - 3L = 4 2G = 4 + 3L Note: Since the ...”
August 10, 2018
GMATGuruNY posted a reply to In a home library consisting of 108 books, some hardcover in the Problem Solving forum
“Goal: To MAXIMIZE the number of nonfiction books. Since the fraction of hardcover books that are nonfiction (2/3) is greater than the fraction of softcover books that are nonfiction (1/4), the number of nonfiction books will be maximized if we must MAXIMIZE THE NUMBER OF HARDCOVER BOOKS. ...”
August 10, 2018
GMATGuruNY posted a reply to A family consisting of one mother, one father, two daughters in the Problem Solving forum
“Case 1: One daughter in the front passenger seat: Since one of the 2 parents must drive, number of choices for the driver''s seat = 2. Since either of the 2 daughters can be in the front passenger seat, number of choices = 2. Number of ways to arrange the 3 remaining people = 3! = 6. To combine ...”
August 10, 2018
GMATGuruNY posted a reply to mgmat 4 in the Data Sufficiency forum
“Fixed! Thanks for pointing out the typo.”
August 10, 2018
GMATGuruNY posted a reply to If the speed of X meters per second is equivalent to the in the Problem Solving forum
“Plug in for x a value that is easy to convert from meters to kilometers. Let x = 1000 meters per second. Since 1000 meters = 1 kilometer, this rate = 1 kilometer per second. Since there are 3600 seconds in an hour, 1 kilometer per second = 3600 kilometers per hour. Thus, y = 3600. This is ...”
August 7, 2018
GMATGuruNY posted a reply to If the average (arithmetic mean) of four different numbers in the Data Sufficiency forum
“Sum of the 4 numbers = (quantity)(average) = 4*30 = 120. Statement 1: Case 1: The four numbers are 32, 31, 30, 27 In this case, two of the numbers are greater than 30. Case 2: The four numbers are 33, 32, 31, 24 In this case, three of the numbers are greater than 30. INSUFFICENT. ...”
August 7, 2018
GMATGuruNY posted a reply to During a one day sale, a store sold each sweater of a in the Data Sufficiency forum
“Statement 1: Case 1: 1 sweater is sold for $270 Case 2: 3 sweaters are sold for $90 each Since the number of sweaters sold can be different values, INSUFFICIENT. Statement 2: Since the $30 markup is 1/2 the cost of each sweater, the cost of each sweater = 60. Thus, the selling price of ...”
August 7, 2018
GMATGuruNY posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum
“If x and y are equal, then their LCM = x = y. Thus, x+y can be the LCM of x and y only if x and y are NOT equal. If x+y is the LCM of x and y, then dividing x+y by x or y must yield an INTEGER. If we divide x+y by x. we get: (x+y)/x = x/x + y/x = 1 + y/x. The expression in blue will be an ...”
August 6, 2018
GMATGuruNY posted a reply to Which of the following CANNOT be the least common multiple in the Problem Solving forum
“Neither x-y nor x+y can be the LCM of x and y. What is the source of this problem?”
August 5, 2018
GMATGuruNY posted a reply to IF N=5^5*10^10*15^15*20^20*25^25*30^30*35^35*40^40*45^45*50^ in the Problem Solving forum
“This problem is about TRAILING 0''s: the number of 0''s at the end of a large product. Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of N will yield a 0 at the end of the integer representation of N.. N=5⁵ * 10¹⁰ * 15¹⁵ * 20²⁰ * 25²⁵ * 30³⁰ ...”
August 5, 2018
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 ...”
August 4, 2018
GMATGuruNY posted a reply to In the figure, angle C and angle M are right angles, and KL in the Data Sufficiency forum
“Statement 1: Since ∠C=∠M=90 and ∠ABC=∠KLM, the remaining two angles are also equal: ∠BAC=∠LKM. Triangles with the same combination of angles are SIMILAR. In similar triangles, corresponding sides in the SAME RATIO. Here, AB and KL are corresponding sides, since each is a ...”
August 4, 2018
GMATGuruNY posted a reply to In the figure, angle C and angle M are right angles, and KL in the Data Sufficiency forum
“Statement 1: Since ∠C=∠M=90 and ∠ABC=∠KLM, the remaining two angles are also equal: ∠BAC=∠LKM. Triangles with the same combination of angles are SIMILAR. In similar triangles, corresponding sides in the SAME RATIO. Here, AB and KL are corresponding sides, since each is a ...”
August 4, 2018
GMATGuruNY posted a reply to A certain junior class has 1,000 students and a certain in the Problem Solving forum
“P(sibling pair) = (total number of sibling pairs)/(total number of possible pairs). Total number of possible pairs: There are 1000 juniors and 800 seniors. Total number of ways to combine 1 junior with 1 senior = 1000*800 = 800,000. Total number of sibling pairs = 60. Thus: ...”
August 4, 2018
GMATGuruNY posted a reply to A software company contracted its sister network in the Data Sufficiency forum
“Statement 1: Case 1: T= 20,000 and L = 10,000, In this case, L/T = 10,000/20,000 = 1/2. Case 2: T = 30,000 and L = 20,000 In this case, L/T = 20,000/30,000 = 2/3. Since L/T can be different values, INSUFFICIENT. Statement 2: In other words, the equipment charge alone is equal to 5/6 of the ...”
August 4, 2018
GMATGuruNY posted a reply to What is the hundredths digit of th decimal Z? in the Data Sufficiency forum
“Statement 1: 100z = 0.2, 1.2, 2.2... Dividing every value by 100, we get the following options for z: z = 0.002, 0.012, 0.022... Since the hundredth digit of z can be different values, INSUFFICIENT. Every value in the blue list above also satisfies Statement 2. Thus -- even when the ...”
August 3, 2018
GMATGuruNY posted a reply to speed and distance in the Data Sufficiency forum
“Regular day: Let r = the regular rate and t = the regular time, implying that the distance to the office = rt. Last Wednesday: Since Mr. David drives 25% faster -- 5/4 of his regular speed -- the rate = (5/4)r. Since Mr. David leaves 30 minutes late -- reducing the time by 30 minutes -- the ...”
August 2, 2018
GMATGuruNY posted a reply to sets in the Problem Solving forum
“To organize the data, use a DOUBLE-MATRIX. 10% of the people do not have a university diploma but have a job of their choice. The following matrix is yielded: https://s33.postimg.cc/ouzby26ln/matrix_diploma_job_1.png 40% people have a job of their choice. The following matrix is yielded: ...”
August 1, 2018
GMATGuruNY posted a reply to Speed/time in the Problem Solving forum
“Since Deb drives for 3/4 of an hour at a rate of 40 mph, the driving distance to work = rt = (40)(3/4) = 30 miles. Since the biking distance is 20% less than the driving distance, the biking distance = 30 - (1/5)(30) = 24 miles. To guarantee an on-time arrival at even the least possible biking ...”
August 1, 2018
GMATGuruNY posted a reply to Mr. Alex usually starts at 9:00am and reaches his office in the Data Sufficiency forum
“20t feet. Statement 1: Since Mr. Alex leaves 20 minutes early last Monday -- giving himself an additional 20 minutes -- the time last Monday = t + 20 minutes. Since Mr. Alex drives 20% slower, the rate last Monday = 20 - (20% of 20) = 16 feet per minute. Thus, the distance traveled last Monday ...”
July 31, 2018
GMATGuruNY posted a reply to What is the median of 10 numbers? in the Data Sufficiency forum
“Statement 1: Case 1: X, X, X, X, 10, 10, X, X, X, X Here, the 6 blue values are all less than or equal to 10. In this case, the median = (10+10)/2 = 10 Case 2: X, X, X, X, 8, 10, X, X, X, X Here, the 6 red values are all less than or equal to 10. In this case, the median = (8+10)/2 = 9. Since ...”
July 31, 2018
GMATGuruNY posted a reply to George and Steven drive separate cars the same distance from in the Data Sufficiency forum
“Statement 1: Here, Steven''s time can be any nonnegative value. INSUFFICIENT. Statement 2: Rate and time have a RECIPROCAL RELATIONSHIP. Since George''s speed in 2/3 Steven''s speed, George''s time is 3/2 Steven''s time. Since George''s time is 3.5 hours, we get: 3.5 = (3/2)t 7 = 3t 7/3 = ...”
July 30, 2018
GMATGuruNY posted a reply to If m=-1 and n = 1^2 + 2^2 + … + 10^2, what is the value of in the Problem Solving forum
“(-1)^odd = -1. (-1)^even = 1. The exponents for the expression in blue are 4 consecutive integers -- n, n+1, n+2, n+3 -- implying that two of the exponents will be ODD, while the other two will be EVEN. Thus, two of the terms in the blue expression must be equal to -1, while the other two must be ...”
July 30, 2018
GMATGuruNY posted a reply to A box of balls originally contained 2 blue balls for every in the Problem Solving forum
“A box of balls originally contained 2 blue balls for every red ball. Let the number of red balls = x and the number blue balls = 2x, implying that the total number of balls = x+2x = 3x. After 12 red balls were added to the box, the ratio of red balls to blue balls became 5 to 2. Since 12 red ...”
July 30, 2018
GMATGuruNY posted a reply to What is the probability of getting only 1 head in a single in the Problem Solving forum
“P(HTT) = 1/2 * 1/2 * 1/2 = 1/8. Since a good outcome will be yielded if H is first, second or third, we multiply by 3: 1/8 * 3 = 3/8. The correct answer is B.”
July 30, 2018
GMATGuruNY posted a reply to Let abcd be a general four-digit number. How many odd four in the Problem Solving forum
“Condition: a*b = integer cd Since abcd must be odd and composed of 4 distinct digits, we get the following options for integer cd: 21, 31, 41, 51, 61, 71, 81, 91 13, 23, 43, 53, 63, 73, 83, 93 15, 25, 35, 45, 65, 75, 85, 95 17, 27, 37, 47, 57, 67, 87, 97 19, 29, 39, 49, 59, 69, 79, 89 ...”
July 29, 2018
GMATGuruNY posted a reply to Two thirds of the roads from A to B are at least 5 miles in the Problem Solving forum
“P(at least one of the 2 selected roads is at least 5 miles long) = 1 - P(neither of the 2 selected roads is at least 5 miles long) From A to B: Since 2/3 of the roads are at least 5 miles long, 1/3 are not. Thus, the probability of selecting a road that is not at least 5 miles long = 1/3. ...”
July 29, 2018
GMATGuruNY posted a reply to If s is the sum of all integers from 1 to 30, inclusive, in the Problem Solving forum
“To calculate the sum of an integer''s positive factors: 1. Prime-factorize the integer 2. Write the prime-factorization in the form (a^p)(b^q)(c^r)... 3. Sum of the factors = (1+a¹+ a²+a³+...+a^p)(1+b¹+ b²+b³+...+b^q)(1+c¹+ c²+c³+...+c^r)... What is the sum of the positive factors of ...”
July 29, 2018
GMATGuruNY posted a reply to In 1990 850 million movie tickets were sold in the United St in the Data Sufficiency forum
“The statement in red does not accurately reflect the information in Statement 2. Statement 2: People under the age of 20 spent $2.2 billion MORE on movie tickets than did people over the age of 50. Here, the total amount spent by people under the age of 20 ≠ $2.2 billion. The usage of MORE ...”
July 28, 2018
GMATGuruNY posted a reply to If a sequence of positive odd integers has six terms contain in the Problem Solving forum
“This problem is invalid. Since the only conditions are that six terms must be positive and odd and have a total of 13 digits, an infinite number of cases are possible. Here are two options: 11, 13, 15, 17, 19, 101 13, 11, 15, 17, 19, 101 Since the sequence does not have to be ascending, any of ...”
July 28, 2018
GMATGuruNY posted a reply to If the sum of 3 consecutive integers is 54, then what is the in the Problem Solving forum
“Average of the 3 consecutive integers = sum/quantity = 54/3 = 18. For any set of consecutive integers, average = median. Thus, the median of the 3 integers = 18, implying that the 3 integers are 17, 18, and 19. Product of the smallest and largest = 17*19 = integer with a units digit of 3. The ...”
July 28, 2018
GMATGuruNY posted a reply to What is the sum of the digits of two-digit positive integer in the Data Sufficiency forum
“Statement 1: Let M = 10T + U, where T = the tens digit and U = the units digit. When the digits are reversed, we get: 10U + T. Since the reversed integer is 27 more than M, we get: (10U + T) - (10T + U) = 27 9U - 9T = 27 9(U-T) = 27 U-T = 3. U = T+3 The resulting equation indicates ...”
July 28, 2018
GMATGuruNY posted a reply to During a 40-mile trip, Marla traveled at an average speed of in the Data Sufficiency forum
“Time and rate are RECIPROCALS. x = the REGULAR speed. 1.25x = the FASTER speed. 1.25x = (125/100)x = (5/4)x. 5/4 the rate implies 4/5 the time. Thus: The time needed at the FASTER speed is equal to 4/5 the time needed at the REGULAR speed. The question stems asks for the following ratio: ...”
July 28, 2018
July 27, 2018
GMATGuruNY posted a reply to A jar contains 12 marbles consisting of an equal number of in the Problem Solving forum
“For only 2 colors to remain after 4 marbles have been removed, the 4 selected marbles must be of the same color. The first selected marble can be of ANY COLOR. A good outcome will be yielded if the second, third and fourth marbles are of the SAME COLOR as the first. P(2nd marble is of the same ...”
July 27, 2018
GMATGuruNY posted a reply to After t seconds, the height of a ball from the ground is giv in the Data Sufficiency forum
“f(x) = ax² + bx + c is the equation of a parabola. If a<0, then the parabola opens DOWNWARD, with a maximum value when: $$x\ =\ \frac{-b}{2a}$$ Given quadratic: h = -9.8t² + ft + g. Here, the maximum height will be yielded when: $$t\ =\ \frac{-f}{\left(2\right)\left(-9.8\right)}$$ ...”
July 27, 2018
GMATGuruNY posted a reply to If the length of each edge of a certain rectangular solid is in the Data Sufficiency forum
“For the solid to have four faces with the same dimensions, two opposing faces must be SQUARES, as in the following figure:https://preview.ibb.co/koZpb8/rectangular_solid_with_square_base.png In the figure above: The area of the square base and the area of the square top = L*L. The areas of the ...”
July 27, 2018
GMATGuruNY posted a reply to Al, Pablo and Marsha shared the driving on a 1,500-mile trip in the Data Sufficiency forum
“Statement 1: No info about Martha. INSUFFICIENT. Statement 2: Distance traveled by Martha = rt = 50*9 = 450 miles. Remaining distance traveled by Al and Pablo = 1500 - 450 = 1050 miles. Case 1: Al''s distance = 1000 miles, Pablo''s distance = 50 miles In this case, Al drives the greatest ...”
July 26, 2018
GMATGuruNY posted a reply to What is the remainder when 7^8 is divided by 100? in the Problem Solving forum
“When an integer is divided by 100, the remainder will have the same units digit as the integer. Thus, to determine which answer choice represents the remainder when 7⁸ is divided by 100, we need to know the units digit of 7⁸. When an integer is raised to consecutive powers, the resulting units ...”
July 26, 2018
GMATGuruNY posted a reply to John and Ed work for the same Sales Company. John receives a in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the amount of profit. Since Ed earns a flat salary of $1000 if the amount of profit does not exceed $8000 -- and all of the answer choices are less than 8000 -- Ed''s earnings = $1000. Since John and Ed must earn the same amount, John must also earn ...”
July 26, 2018
GMATGuruNY posted a reply to In how many ways can 6 chocolates be distributed among 3 in the Problem Solving forum
“We can apply the SEPARATOR METHOD, which I describe here: https://www.beatthegmat.com/combinations-t120668.html To solve the problem above, we need 6 identical chocolates and 2 identical separators, as follows: OO|OO|OO. The number of ways to arrange 8 elements composed of 6 identical ...”
July 26, 2018
GMATGuruNY posted a reply to Please explain in the Sentence Correction forum
“This line of reasoning applies to a VERBing modifier preceded by CLAUSE + COMMA. In C, making is preceded not by CLAUSE + COMMA but by a NOUN PHRASE (a part of a deal). The referent for this noun phrase is unclear, as discussed in my earlier post. As a result, a reader cannot be sure whether ...”
July 25, 2018
GMATGuruNY posted a reply to For integers x and y, 25^(−10)*100^x=2^y. What is the valu in the Problem Solving forum
“25¯¹⁰ * 100^x = 2^y 1/25¹⁰ * (25*4)^x= 2^y (1/25¹⁰)(25^x)(4^x) = 2^y In the resulting blue equation, x and y will be integers if x=10, with the result that (25^x)/25¹⁰ = 1. Substituting x=10 into the blue equation, we get: (25¹⁰/25¹⁰) * 4¹⁰ = 2^y 4¹⁰ = ...”
July 25, 2018
GMATGuruNY posted a reply to CEO in the Sentence Correction forum
“C: CEOs now earn 419 times the pay of blue-collar workers, as compared to 42 times their pay. Because the two blue portions are parallel, their pay clearly refers to the pay of blue-collar workers.”
July 25, 2018
GMATGuruNY posted a reply to CEO in the Sentence Correction forum
“The construction in red is acceptable when it serves to express how a subject CHANGES. An OA in the OG for Verbal: Its numbers are now five times greater than when the use of DDT was sharply restricted in the early 1970. Here, the portion in blue serves to express how ITS NUMBERS have changed ...”
July 25, 2018
GMATGuruNY posted a reply to If p is a prime number and n is a positive integer, what is in the Data Sufficiency forum
“To count the factors of a positive integer: 1. Prime-factorize the integer 2. Write the prime-factorization in the form Statement 1: Test one case that also satisfies Statement 2. Case 1: p=5, with the result that (3^n)(p^2) = 3⁴5² Adding 1 to each exponent and multiplying, we get: Number ...”
July 25, 2018
GMATGuruNY posted a reply to If x and y are integers such that (xy)^2 + x^2 – 2xy – 2 in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of y. B: y=-1 Substituting y=-1 into (xy)² + x² – 2xy – 2x + 2 = 0, we get: x² + x² + 2x – 2x + 2 = 0 2x² + 2 = 0 x² + 1 = 0 x² = -1 Since the square of a value cannot be negative, eliminate B. D: y=1 Substituting y=1 ...”
July 25, 2018
GMATGuruNY posted a reply to A bus trip of 450 miles would have taken 1 hour less if the in the Problem Solving forum
“Since the time difference yielded by the two speeds is an INTEGER -- 1 hour less -- the actual speed and hypothetical greater speed must both divide evenly into the 450-mile distance. We can PLUG IN THE ANSWERS, which represent the actual speed. Since A, B and E do not evenly into 450, eliminate ...”
July 25, 2018
GMATGuruNY posted a reply to Is the United States Singular or plural? in the Sentence Correction forum
“Correct.”
July 25, 2018
GMATGuruNY posted a reply to During a 6-day local trade show, the least number of people in the Data Sufficiency forum
“Statement 1: Average for 4 of the 6 days = 100 per day. Least possible average for the other 2 days = 80 per day. Since there are MORE DAYS with an average of 100 per day than with an average of at least 80 per day, the average for all 6 days must be CLOSER TO 100 THAN TO 80. Thus, the average ...”
July 24, 2018
GMATGuruNY posted a reply to Each week a certain salesman is paid a fixed amount equal to in the Data Sufficiency forum
“One way to evaluate Statement 1 is to test whether the value given in Statement 2 -- $5000 in sales -- is the ONLY value that will also satisfy Statement 1. Statement 1: The total amount the salesman was paid last week is equal to 10 percent of the amount of his sales last week. Case 1: Let ...”
July 24, 2018
GMATGuruNY posted a reply to Machines X and Y produced identical bottles at different in the Data Sufficiency forum
“Statement 1: X produced 30 bottles per minute. Thus, the work produced by X in 240 minutes = r*t = 30*240. No information about how much work was produced by Y. INSUFFICIENT. Statement 2: Machine X produced twice as many bottles in 4 hours as Machine Y produced in 3 hours. Thus, for ...”
July 24, 2018
GMATGuruNY posted a reply to Is xy > 0 ? in the Data Sufficiency forum
“Statement 1: x > y-2 If y=2 and x= 1, is 1*2 > 0? Yes. If y= -1 and x = 1, is 1*(-1) > 0? No. Since the answer is YES in the first case but NO in the second case, INSUFFICIENT. Statement 2: x < 2y-6 If y=1 and x = -10, is 1*(-10) > 0? No. If y = 10 and x = 1, is 1*10 > ...”
July 24, 2018
GMATGuruNY posted a reply to There are 3 ways to make the number 12 using products of two in the Problem Solving forum
“To count the factors of a positive integer: 1. Prime-factorize the integer 2. Write the prime-factorization in the form (a^p)(b^q)(c^r)... 3. The number of factors = (p+1)(q+1)(r+1).. 2700 = 2²3³5² Adding 1 to each exponent and multiplying, we get: Total number of factors = ...”
July 24, 2018
GMATGuruNY posted a reply to Number Systems -Sequence and Series in the Problem Solving forum
“Good catch! I''ve corrected the typo.”
July 24, 2018
GMATGuruNY posted a reply to If john makes a contribution to a charity fund at school in the Problem Solving forum
“Since $75 is 50% more than $50, the first 5 contributions were worth an average of $50. Thus, the sum of the first 5 contributions = 5*50 = 250. Since the average of all 6 contributions = $75, the sum of all 6 contributions = 6*75 = 450. Thus, John''s contribution = (sum of all 6 contributions) - ...”
July 23, 2018
GMATGuruNY posted a reply to How many positive integers less than 28 are prime numbers, in the Problem Solving forum
“Any even integer other than 2 and 4 can be expressed as the sum of a positive multiple of 2 and a positive multiple of 4, yielding the following options less than 28: 6, 8, 10, 12, 14, 16, 18, 20, 22, 24, 26 --> 11 options. Prime numbers less than 28: 2, 3, 5, 7, 11, 13, 17, 19, 23 --> 9 ...”
July 23, 2018
GMATGuruNY posted a reply to If m is a two-digit number, what is the remainder when m is in the Data Sufficiency forum
“Statement 1: Make a list of options for m+1: m+1 = 12, 15, 18, 21, 24, 27... To get a list option for m, subtract 1 from every value in the list above: m = 11, 14, 17, 20, 23, 26... When any value in the resulting list is divided by 3, the remainder in every case is 2. SUFFICIENT. Statement ...”
July 23, 2018
GMATGuruNY posted a reply to A credit card company has a cash back option for their in the Problem Solving forum
“(1.5% of 5000) + (2.5% of 5000) = 75 + 125 = 200. We can PLUG IN THE ANSWERS, which represent the total annual charge. When the correct answer is plugged in, the cash back will be 2.6% of the total annual charge. D: 26,000 Since 3% is earned on the amount over $10,000 -- in other words, since ...”
July 23, 2018
GMATGuruNY posted a reply to The ratio of spinsters to cats is 2 to 7. If there are 25 in the Problem Solving forum
“Given ratio = S:C = 2:7. The difference between the parts of the ratio = 7-2 = 5. Since the actual difference between the number of cats and the number of spinsters is five times as great -- 25 -- each part of the ratio must be multiplied by a FACTOR OF 5: S:C = (2*5) : (7*5) = 10:35, with the ...”
July 22, 2018
GMATGuruNY posted a reply to At the start of the day the amount of water in two identical in the Problem Solving forum
“Since the resulting ratio = A:B = 3:10, and all of the values in the problem are integers, the correct answer must yield a multiple of 10 when added to the 2 original liters in B. Only D is viable: 48+2 = 50 liters. The correct answer is D.”
July 22, 2018
GMATGuruNY posted a reply to An airplane was due north of a tropical island when in the Data Sufficiency forum
“Statements combined: https://preview.ibb.co/i0YOtd/plane.png The dotted green line indicates the plane''s position at 12pm. The blue right triangle indicates the plane''s position at 3pm. The two dotted red lines show positions for the island that are 450 miles from the plane''s position at ...”
July 22, 2018
GMATGuruNY posted a reply to Is the average age of a class of 60 students more than 30 in the Data Sufficiency forum
“If the average age of the students is exactly 30, then the sum of the 60 ages = 60*30 = 1800. Implication: For the average age to be GREATER THAN 30, the SUM of the 60 ages must be GREATER THAN 1800. Question stem, rephrased: Is the sum of the 60 ages greater than 1800? Statement 1: Since ...”
July 22, 2018
GMATGuruNY posted a reply to Each day a man meets his wife at the train station after in the Problem Solving forum
“Normal day: 4pm --> The wife leaves home and drives to the station. 5pm --> The husband''s train and the wife both arrive at the station. 6pm --> The husband and wife arrive home. Implication: The normal driving time in each direction = 60 minutes. Today: Since the wife and the ...”
July 21, 2018
GMATGuruNY posted a reply to In how many different ways can a group of twelve people be in the Problem Solving forum
“Since there are 12 people, the first person selected can be paired with any of the 11 other people, yielding 11 POSSIBLE PAIRS. Since 2 of the 12 people have been selected thus far, the number of people remaining = 12-2 = 10. Since 10 people remain, the next person selected can be paired with ...”
July 20, 2018
GMATGuruNY posted a reply to A total of $60,000 was invested for one year. But of this in the Data Sufficiency forum
“Since 4080 is between 5% and 10% of 60,000, it is likely that x and y are between 5 and 10. Statement 1: x = (3/4)y It''s possible that x=6 and y=8 or that x=6.6 and that y=8.8. To accommodate the desired combination of percentages, we could simply adjust the amount invested at each percentage ...”
July 19, 2018
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 ...”
July 19, 2018
GMATGuruNY posted a reply to If Bob produces 36 or fewer items in a week, he is paid X in the Data Sufficiency forum
“When the two statements are combined, the 2 additional items produced this week result in an earnings increase of $30 (from $480 to $510). Thus, the amount earned by each of the 2 additional items produced this week = 30/2 = 15. It is possible that these 2 additional items were paid at the ...”
July 19, 2018
GMATGuruNY posted a reply to If An=An-1/An-2 (n3), A1=1, and A2=-2, then A100=? in the Problem Solving forum
“A₁ = 1 A₂ = -2 A₃ = -2/1 = -2 A₄ = -2/-2 = 1 A₅ = 1/-2 = -0.5 A₆ = -0.5/1 = -0.5 A₇ = -0.5/-0.5 = 1 A₈ = 1/-0.5 = -2 As illustrated by the results in blue, A₁ through A₆ represent one complete 6-term CYCLE: 1, -2, -2, 1, -0.5, -0.5 Starting with A₇ and A₈, the ...”
July 19, 2018
GMATGuruNY posted a reply to If m and n are positive integers, what is the value of m + n in the Data Sufficiency forum
“Statement 1: Since m must be a positive integer, only two cases are possible: Case 1: m=1, with the result that m² = 1 Case 2: m=2, with the result that m² = 4 Since the value of n is unknown, INSUFFICIENT. Statement 2: m = n+1 Case 1: n=1, with the result that m=2 and m+n = 3 Case 2: ...”
July 19, 2018
GMATGuruNY posted a reply to If 75 percent of the guests at a certain banquet ordered in the Data Sufficiency forum
“Let the total number of guests = 100. Since 75% of the guests ordered dessert, we get: Total desert = 0.75(100) = 75. Let C = total who ordered coffee. Let B = total who ordered both dessert and coffee. Statement 1: 60% of the guests who ordered dessert also ordered coffee. Thus: B = ...”
July 19, 2018
GMATGuruNY posted a reply to Please explain in the Sentence Correction forum
“It must be crystal clear what a modifier is modifying. C: The computer company has announced that it will purchase the color-printing division of a rival company for $950 million, a part of a deal making it the largest manufacturer in the office color-printing market. Here, the intended ...”
July 18, 2018
GMATGuruNY posted a reply to <x> is the largest integer less than or equal to x and in the Problem Solving forum
“Let x = 0.5. < x > = <0.5> = the largest integer less than 0.5 = 0. A.”
July 17, 2018
GMATGuruNY posted a reply to Patrick purchased 80 pencils and sold them at a loss equa in the Problem Solving forum
“Since the two blue values above are equal, the given question stem is the same as the following: The cost of EACH PENCIL is how many times the selling price of EACH PENCIL? Let the selling price of each pencil = $1. Thus, the selling price of 80 pencils = $80. Since Patrick''s loss is equal ...”
July 17, 2018
GMATGuruNY posted a reply to If x < 12, then it must be true that in the Problem Solving forum
“If x=-100, then A, B and C are not true. If x=11, then D is not true. The correct answer is E. E: x-2 < 11 x < 13. Since the prompt indicates that x<12, x must be less than 13. Thus, E must be true.”
July 17, 2018
GMATGuruNY posted a reply to What is the probability that a 3-digit positive integer in the Problem Solving forum
“P(at least one 7) = 1 - P(no 7''s). P(no 7''s): P(hundreds digit is not 7) = 8/9. (Of the 9 possible digits that could serve as the hundreds digit, eight are not 7.) P(tens digit is not 7) = 9/10. (Of the 10 possible digits that could serve as the tens digit, nine are not 7.) P(units digit is ...”
July 17, 2018
GMATGuruNY posted a reply to There are 4 bottles with the same number balls in the Problem Solving forum
“Let the total number of balls = the sum of the parts of the final ratio = 1+6+5+4 = 16. Since there are 16 balls in total, and each of the 4 bottles begins with m balls, m=4. Since the number of balls in the first bottle decreases from 4 to 1, the number of balls moved from the first bottle = ...”
July 17, 2018
GMATGuruNY posted a reply to What is the mean number of defective pens in a box of pens? in the Data Sufficiency forum
“Statements combined: Since all the values are PERCENTS, there is no way to determine the average number of defective pens per box. Consider the following cases: Case 1: Each box contains 100 pens. Case 2: Each box contains 1,000,000 pens. Clearly, the average number of defective pens in Case 1 ...”
July 16, 2018
GMATGuruNY posted a reply to If t is the sum of three consecutive positive integers, is t in the Data Sufficiency forum
“Let the three consecutive integers be x, x+1 and x+2. Thus: t = x + (x+1) + (x+2) = 3x + 3 = 3(x+1). Statement 1: Since x = even, get get: t = 3(EVEN + 1) = ODD*ODD = ODD. An odd integer has no even factors. Since t is odd and thus has no even factors, it cannot be divisible by 24, which is ...”
July 16, 2018
GMATGuruNY posted a reply to Time and work problem in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent how many times a man''s output exceeds that of a woman. When the correct answer is plugged in, 3 men will take 5 fewer days to complete the job than 9 women. B: 4 Let the rate for each woman = 1 unit per day and the rate for each man = 4 units per ...”
July 16, 2018
GMATGuruNY posted a reply to In the rectangular coordinate system in the Data Sufficiency forum
“Statement 1: Thus, OP=12. Case 1: OQ=1, QS=1, and RS=12, with the result that the area of reach triangle = (1/2)(1)(12) = 6 In this case, R = (2, 12). Case 2: OQ=1, QS=12, and RS=1, with the result that the area of reach triangle = (1/2)(1)(12) = 6 In this case, R = (13, 1). Since R can have ...”
July 15, 2018
GMATGuruNY posted a reply to As envisioned by researchers, commercial farming of lobsters in the Sentence Correction forum
“A: to sell...standardize...and to predict D: to sell...take...and to predict E: to sell...take...to standardize...and to predict In each of these options, the verb form in red is not parallel with the surrounding infinitives in blue. Eliminate A, D and E. C: taking advantage of off-season ...”
July 14, 2018
GMATGuruNY posted a reply to Students in a class are arranged to form groups of 4 in the Data Sufficiency forum
“Let T = the total number of students. Since Statement 1 constrains T to a value less than 65, determine whether it''s possible that T<65 or that T≥65. Students in a class are arranged to form groups of 4 members each. After forming the groups, 3 students are left. Thus, T is equal to 3 ...”
July 14, 2018
GMATGuruNY posted a reply to doubt 2 in the Sentence Correction forum
“A: The protein in rice is higher quality. This wording implies that protein is a type of quality -- a nonsensical meaning. Eliminate A. Since the meaning is nonsensical, the comparison issue is moot.”
July 13, 2018
GMATGuruNY posted a reply to doubt 2 in the Sentence Correction forum
“Yes -- SC19 in the OG10.”
July 13, 2018
GMATGuruNY posted a reply to If a certain positive integer is divided by 9, the remainder in the Data Sufficiency forum
“Let x = the integer. If a certain positive integer is divided by 9, the remainder is 3. In other words, x is 3 more than a multiple of 9: x = 9a + 3 = 3, 12, 21, 30.... Statement 1: If the integer is divided by 45, the remainder is 30. In other words, x is 30 more than a multiple of 45: x = ...”
July 13, 2018
GMATGuruNY posted a reply to tricky odd/even integer question in the Data Sufficiency forum
“Statement 1: Test whether it''s possible that x is odd. Let x=1. Substituting x=1 into xy+z = ODD, we get: y+z = ODD Substituting x=1 into xy+xz = EVEN, we get: y+z = EVEN The equations in red contradict each other, implying that it is not possible that x is odd. Thus, x must be even. ...”
July 13, 2018
GMATGuruNY posted a reply to In a certain office, 50 percent of the employees are 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 red, we ...”
July 13, 2018
GMATGuruNY posted a reply to If a, b, and c are consecutive integers and a<b<c, is in the Data Sufficiency forum
“Case 1: a, b and c are EVEN-ODD-EVEN Case 2: a, b and c are ODD-EVEN-ODD Statement 1: Here, Case 2 is not possible: if a and c are both odd, then ac will be odd and thus not a multiple of 8. Since only Case 1 is possible, a must be even. SUFFICIENT. Statement 2: Case 1 is possible if a, b ...”
July 13, 2018
GMATGuruNY posted a reply to If the sequence {An } satisfies An = An-1 - An-2, A1 = 0, an in the Problem Solving forum
“A₁ = 0. A₂ = 1. A₃ = A₂ - A₁ = 1 - 0 = 1. A₄ = A₃ - A₂ = 1 - 1 = 0. A₅ = A₄ - A₃ = 0 - 1 = -1. A₆ = A₅ - A₄ = -1 - 0 = -1. A₇ = A₆ - A₅ = -1 - (-1) = 0. A₈ = A₇ - A₆ = 0 - (-1) = 1. The alternating blue and red implies the following pattern: 0, 1, ...”
July 12, 2018
July 11, 2018
GMATGuruNY posted a reply to Each of three charities in Novel Grove Estates has 8 persons in the Problem Solving forum
“This problem involves 3 overlapping sets: Charity A, Charity B, and Charity C. To organize the data, use a Venn Diagram: https://preview.ibb.co/fuXOMo/ABC_0.png Start in the CENTER and work outwards. Exactly 4 persons serve on 3 boards each. Inserting 4 people into the center of the ...”
July 11, 2018
GMATGuruNY posted a reply to Challenge: If line k passes through the points (48, 33) and in the Problem Solving forum
“Slope = ∆y/∆x = (33-22)/(48-31) = 11/17. Since (x, 0) and (31, 22) must yield the same slope, we get: (0-22)/(x-31) = 11/17 (x-31)(11) = (17)(-22) x - 31 = (17)(-2) x - 31 = -34 x = -3. The correct answer is B.”
July 11, 2018
GMATGuruNY posted a reply to If gcd(m,n) is the greatest common divisor of m and n, then in the Data Sufficiency forum
“Statement 1: Case 1: m=1 and n=1, with the result that gcd(m,n)=gcd(1,1)=1 Case 2: m=2 and n=2, with the result that gcd(m,n)=gcd(2,2)=2 Since n can be different values, INSUFFICIENT. Statement 2: Case 1: m=30 and n=30, with the result that gcd(m,n)=gcd(30,30)=30 and ...”
July 11, 2018
GMATGuruNY posted a reply to The terms of the sequence {An} satisfy A2 - A1 = 2, A3 - A2 in the Problem Solving forum
“Let n=3. According to the blue portion above, An+1 - An = A4 - A3 = 10. The correct answer must yield a result of 10 when n=3. Only B works: n² + 1 = 3² + 1 = 10. The correct answer is B.”
July 11, 2018
GMATGuruNY posted a reply to When the positive integer n is divided by 8, the remainder i in the Problem Solving forum
“When the positive integer n is divided by 8, the remainder is 3. In other words, n is 3 more than a multiple of 8: n = 8a + 3, where a is nonnegative integer. Options for n: 3, 11, 19, 27... When n is divided by 5, the remainder is 2. In other words, n is 2 more than a multiple of 5: n = 5b ...”
July 10, 2018
GMATGuruNY posted a reply to |m-n|=? in the Data Sufficiency forum
“{m-n| = the distance between m and n. Question stem, rephrased: What is the distance between m and n? Statement 1: Clearly INSUFFICIENT. Statement 2: Case 1: m=13 and n=1, with the result that the distance between m and n is 12 Case 2: m=100 and n=13/100, with the result that the distance ...”
July 10, 2018
GMATGuruNY posted a reply to The average age of a class of 10 students is 15. in the Problem Solving forum
“Alternate approach: Since the average age of the 10 original students = 15, the sum of the original 10 ages = (count)(average) = 10*15 = 150. One year later, each of the 10 students is 1 year older, increasing the sum of the ages by a total of 10 years: 150+10 = 160. After the addition of a ...”
July 9, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 Biologists with a predilection in the Critical Reasoning forum
“Passage: We must be open to the possibility that there are living things on other planets. Therefore, we will not be successful in defining what it is that makes something a living thing merely by examining living things on Earth. The statement in blue suggests the following: We cannot define an ...”
July 8, 2018
GMATGuruNY posted a reply to If x is an integer and y=3x+2, which of the following CANNOT in the Problem Solving forum
“Rule: MULTIPLE OF K + MULTIPLE OF K = MULTIPLE OF K MUTIPLE OF K + NON-MULTIPLE OF K = NON-MULTIPLE OF K y = 3x + 2 = MULTIPLE OF 3 + NON-MULTIPLE OF 3 = NON-MULTIPLE OF 3. Since y is not a multiple of 3, it cannot be a multiple of 6. The correct answer is C.”
July 8, 2018
GMATGuruNY posted a reply to Is the United States Singular or plural? in the Sentence Correction forum
“United States is singular. The OA employs the COMMAND SUBJUNCTIVE. The structure of the command subjunctive is BOSSY WORD + THAT + NOUN + BARE INFINITIVE. A bossy word serves to express a command or recommendation: requires, suggests, recommends, insists, etc. The bare infinitive is the ...”
July 8, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 (1/2 - 1/3) + (1/3-1/4) in the Problem Solving forum
“All the values between the first term and the last term CANCEL OUT. If we subtract the last term from the first term, we get: $$\ \frac{1}{2}-\frac{1}{6}=\ \frac{3}{6}-\frac{1}{6}=\frac{2}{6} = \frac{1}{3}$$ The correct answer is C.”
July 8, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 If S = 1 + in the Problem Solving forum
“BALLPARK. After the first four terms, the values are so small that they can be ignored. Approximate the sum of the first four terms: $$If\ S\ ≈\ 1\ +\ \frac{1}{4}+\frac{1}{10}+\frac{1}{15} = \ 1\ +\ \frac{15}{60}+\frac{6}{60}+\frac{4}{60} = \ 1\ +\ \frac{25}{60}$$ The resulting sum ...”
July 8, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 Over the past ten years in the Sentence Correction forum
“In B and C, second in importance is redundant. X is second to Y means -- all on its own -- that X is less important than Y. Eliminate B and C. Modifiers such as only and almost are known as LIMITERS. A limiter serves to LIMIT the scope of another word in the sentence. Generally, a limiter ...”
July 7, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 Many utilities obtain most of in the Sentence Correction forum
“In A, B, and D, higher as is unidiomatic. Correct: X is higher THAN Y Eliminate A, B and D. E: between two to three Here, between...to is unidiomatic. Correct: between X AND Y Eliminate E. The correct answer is C.”
July 7, 2018
GMATGuruNY posted a reply to In the x-y plane, y = f(x) = ax^2+bx+c passes through (1,0) in the Data Sufficiency forum
“f(x) = ax²+bx+c will be a U-shaped parabola if a>0. f(x) = ax²+bx+c will be a ∩-shaped parabola if a<0. Since f(x) = ax²+bx+c has x-intercepts at (1, 0) and (2, 0), f(3)>0 if the parabola is U-shaped. Question stem, rephrased: Is the parabola U-shaped? Statement 1: Since ...”
July 6, 2018
GMATGuruNY posted a reply to John invested 1/4 of A dollars in an investment fund, and pl in the Problem Solving forum
“Let A=40. Since John invests 1/4 of his money in the fund, the amount invested in the fund = (1/4)(40) = 10. Since the remainder is placed in the savings account, the amount placed in the savings account = 40−10 = 30. Since 4p = 4∗10 = 40%, John loses 40% of his $10 investment in the ...”
July 6, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 In a set of 24 cards, each in the Problem Solving forum
“P = (good outcomes)/(all possible outcomes) All possible outcomes: Since there are 24 cards, there are 24 possible outcomes. Good outcomes: For a number to be divisible by 2 and 3, it must be a multiple of 6. Multiples of 6 between 1 and 24, inclusive: 6, 12, 18, 24 For a number to be ...”
July 6, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 Which of the following is closest in the Problem Solving forum
“$$\sqrt{\frac{4.2\left(1,590\right)}{15.7}}$$ $$\sqrt{\frac{4\left(1600\right)}{16}}$$ $$\sqrt{\frac{1600}{4}}$$ $$\sqrt{400}$$ $$20$$ The correct answer is A.”
July 6, 2018
GMATGuruNY posted a reply to If positive integer p divided by 9 leaves a remainder of 1 in the Problem Solving forum
“Since dividing p by 9 yields a remainder of 1, p is ONE MORE THAN MULTIPLE OF 9: p = 9a + 1, where a is a nonnegative integer. Options for p 1, 10, 19, 28... If p=1, then Statement I is not true. Eliminate A, D and E. If p=10, then Statement II is not true. Eliminate B. The correct ...”
July 5, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 If n is an integer, what in the Data Sufficiency forum
“Statement 1: 12n = 432. Since we can solve for n, the GCF of 12 and n can be determined. SUFFICIENT. Statement 2: 24 = 2*2*2*3. Since the GCF of n and 24 is the blue product (12) without the red factor (2), n must be a multiple of 12 that does NOT include an additional factor of 2. In ...”
July 5, 2018
GMATGuruNY posted a reply to |x-y|=? in the Data Sufficiency forum
“Statement 1: Clearly INSUFFICIENT. Statement 2: If x=5 and y=1, then |x-y| = |5-1| = 4. If x=10 and y=0.5, then |x-y| = |10-0.5) = 9.5. Since |x-y| can be different values, INSUFFICIENT. Statements combined: If x=5 and y=1, then |x-y| = |5-1| = 4. If x=1 and y=5, then |x-y| = |1-5| = 4. ...”
July 4, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 The table shows partial results in the Problem Solving forum
“Percent who indicated coupons or store displays = 22+18 = 40. Total percent surveyed = 35+22+18+15 = 90. Resulting fraction: 40/90 = 4/9. The correct answer is D.”
July 4, 2018
GMATGuruNY posted a reply to If f(x) = 4x^2 + px, what is the minimum value of f(x)? in the Data Sufficiency forum
“To determine the minimum value of the graph, we need to know the value of p. Question stem, rephrased: What is the value of p? Statement 1: Substituting x=1 and f(x)=−4 into f(x) = 4x² + px, we get: -4 = 4(1)² + p(1) Since we can solve for p, SUFFICIENT. Statement 2: Substituting ...”
July 4, 2018
GMATGuruNY posted a reply to Which of the following equations has a graph that can pass t in the Problem Solving forum
“Eliminate the four answer choices with MORE THAN ONE coordinate pair (x, y ) such that x and y are integers. If x=1, integer values for y are yielded by A, C, D and E. If x=-1, integer values for y are yielded by A, C, D and E. Since each of these options has more than one coordinate pair (x, y ) ...”
July 3, 2018
GMATGuruNY posted a reply to If n is positive integer, is 21 a factor of n? in the Data Sufficiency forum
“Statement 1: In other words, 3n is a multiple of 21: 3n = 21, 42, 63... To get a list of options for n, divide every value above by 3: n = 7, 14, 21... If n=7, then the answer to the question stem is NO. If n=21, then the answer to the question stem is YES. INSUFFICIENT. Statement 2: ...”
July 3, 2018
GMATGuruNY posted a reply to OG SC question #171 "so as to vs so that" in the Sentence Correction forum
“Please see my explanation: https://www.beatthegmat.com/gmat-og-2019-technically-a-quicksanda-is-the-term-t302953.html”
July 2, 2018
GMATGuruNY posted a reply to GMAT OG 2019 Technically, “quicksand” is the term in the Sentence Correction forum
“I received a PM requesting that I explain why A is wrong. There are several reasons to eliminate A and choose B. so X as to Y implies that Y SEEMS TO BE TRUE. Official examples: Climatic shifts are so gradual as to be indistinguishable from ordinary fluctuations in the weather. The features ...”
July 2, 2018
GMATGuruNY posted a reply to If a rectangular box has two faces with an area of 30 in the Problem Solving forum
“Nice approach. Just one suggestion: Rather than calculate the product of 60, 30 and 72, break the factors into perfect squares, as follows: V² = 30 * 60 * 72 V² = 30 * 30 * 2 * 2 * 36 V = √(30*30) * √(2*2) * √(6*6) V = 30*2*6 = 360.”
July 2, 2018
GMATGuruNY posted a reply to n=? in the Data Sufficiency forum
“Statement 1: Case 1: n=1, with the result that n² = 1² = 1 Case 2: n=-1, with the result that n² = (-1)² = 1 Since n can be different values, INSUFFICIENT. Statement 2: Here, the only one option for n is possible: n=1. SUFFICIENT. The correct answer is B.”
July 2, 2018
GMATGuruNY posted a reply to A certain company employs 6 senior officers and 4 junior in the Problem Solving forum
“From 6 senior officers, the number of ways to choose 3 for the committee = 6C3 = (6*5*4)/(3*2*1) = 20. Since there are 4 junior officers, the number of options for the junior officer on the committee = 4. To combine the options above, we multiply: 20*4 = 80. The correct answer is D.”
July 2, 2018
GMATGuruNY posted a reply to Jamshid can paint a fence in 50 percent less time than in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent Taimour''s time alone. Since Jamshid and Taimour working together takes 8 hours to paint the fence, Taimour''s time alone must be more than 8 hours. Eliminate A and B. When the correct answer is plugged in, Jamshid''s time alone will be 50% less than ...”
July 2, 2018
GMATGuruNY posted a reply to If z^n = 1, what is the value of z? in the Data Sufficiency forum
“Statement 1: Case 1: z=1 and n=1, with the result that z^n = 1¹ = 1 Case 2: z=-1 and n=2, with the result that z^n = (-1)² = 1 Since z can be different values, INSUFFICIENT. Statement 2: Case 1: z=1 and n=1, with the result that z^n = 1¹ = 1 Case 2: z=2 and n=0, with the result that z^n = ...”
July 2, 2018
GMATGuruNY posted a reply to If a rectangular box has two faces with an area of 30 in the Problem Solving forum
“Let LW = 72 such that L=6 and W=12. Since the other two given areas are 30 and 60, H=5: LH = 6*5 = 30. WH = 12*5 = 60. Thus: V = LWH = 6*12*5 = 360. The correct answer is E.”
July 2, 2018
GMATGuruNY posted a reply to What is the remainder when 1044*1047*1050*1053 is in the Problem Solving forum
“This problem is beyond the scope of the GMAT. Feel free to ignore it.”
July 2, 2018
GMATGuruNY posted a reply to A shelf contains only books of poetry, short stories, in the Data Sufficiency forum
“Neither statement alone offers any information about the number of nonfiction books. Statements combined: Number of nonfiction books = (total number of books) - (poetry books) - (short story books) = 15 -4-5 = 6. Since 6 of the 15 books are nonfiction, we get: P(selecting a nonfiction book) = ...”
July 2, 2018
GMATGuruNY posted a reply to Challenge question: If j and k are positive integers, and (k in the Problem Solving forum
“Options for j such that j⁶ will divide into 29²⁹11¹¹: j=1 j=11 j=29 j=29² j=29³ j=29⁴ j=11*29 j=11*29² j=11* 29³ j=11*29⁴ Since there are 10 options for j, there are 10 options for k. The correct answer is B.”
July 1, 2018
GMATGuruNY posted a reply to Thomas Eakins' powerful style-The present perfect tense coul in the Sentence Correction forum
“The rule to which you are referring is discussed at length in my posts here: https://www.beatthegmat.com/comparison-t289039-15.html This rule is applicable only when the adjective in each clause is THE SAME: Its numbers are now five times greater than great] when the use of DDT was sharply ...”
July 1, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 From 2000 to 2003, the number in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of employees in 2000. Since the number of employees increases by 1/4 and then decreases by 1/3, the correct answer must be divisible by 4 and 3. In other words, the correct answer must be a MULTIPLE OF 12. Eliminate A, C and D. Since the ...”
July 1, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 Last year $48,000 of a in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the share for each owner. Since the share for each owner is 3 times the share for each employee, the correct answer is almost certainly a multiple of 3 (A, B, C or E). When the correct answer is plugged in, the total profit = 48,000. B: $9000 for each ...”
July 1, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 Robin invested a total of $12,000 in the Data Sufficiency forum
“Since X and Y constitute a total investment of $12,000, we get; X + Y = 12,000 Statement 1: Since 3% of X must yield the same amount of interest as 6% of Y, we get: 0.03X = 0.06Y Since we have two variables (X and Y) and two distinct linear equations (X+Y=12000 and 0.03X=0.06Y), we can solve ...”
June 30, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 If x is a positive integer in the Problem Solving forum
“Subtract 3 from increasing powers of 4: 4¹ - 3 = 1 4² - 3 = 13 The results above indicate that the following case is not possible: $$4^x - 3 = 7$$ The correct answer is B.”
June 30, 2018
GMATGuruNY posted a reply to If Alice traveled on a 10 km trip at a constant speed of 25 in the Problem Solving forum
“Since Alice travels only a small portion of the total distance at 25 kph but the vast majority of the entire distance at 30 kph, her average speed for the entire trip must be just a bit less than 30 kph. Of the five answer choices, only C is sufficiently close to 30 kph. The correct answer is C.”
June 29, 2018
GMATGuruNY posted a reply to A cashier mentally reversed the digits of one customer's in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the correct amount of change. When the digits in the correct answer are reversed, the resulting integer must yield a decrease of 45 cents -- the 45 cents left in the register by mistake. Since reversing the digits must yield a decrease of 45 cents, the ...”
June 28, 2018
GMATGuruNY posted a reply to Tom, who has 50 math questions, will get 5 points in the Problem Solving forum
“Since each question is worth 5 points, a perfect score on the 50-question test = 50*5 = 250. For every question missed, Tom will forgo the 5 points attributed to the question and will lose another 2 points for missing the question, for a net loss of 7 points per missed question. Thus, Tom''s score ...”
June 28, 2018
GMATGuruNY posted a reply to Of the integers between 100 and 799, inclusive in the Problem Solving forum
“Number of options for the hundreds digit = 5. (Of the seven digits 1-7, any but 2 or 5.) Number of options for the tens digit = 8. (Of the ten digits 0-9, any but 2 or 5.) Number of options for the units digit = 8. (Of the ten digits 0-9, any but 2 or 5.) To combine these options, we multiply: ...”
June 28, 2018
GMATGuruNY posted a reply to What is the greatest possible (straight line) distance in the Problem Solving forum
“The longest line that can be drawn inside a rectangular solid is called the MAIN DIAGONAL. Use the SUPER-PYTHAGOREAN THEOREM. If d = the length of the main diagonal, then: d² = l² + w² + h². In the problem above: d² = 10² + 10² + (0.1)² d² = 100 + 100 + 0.01 d² = 200.01 ...”
June 28, 2018
GMATGuruNY posted a reply to 3^n+3^{n+1}+3^{n+2}/3^{n-2}+3^{n-1}+3^n=? in the Problem Solving forum
“Both C and D yield a value of 3² when n=2. As a result, a test-taker would have to test another case to determine whether the correct answer is C or D. When plugging in values, we should avoid numbers that appear in the answer choices. Here -- since 2 appears in the answer choices -- we should ...”
June 28, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 [What was the median annual] in the Data Sufficiency forum
“The median salary is equal to the 15th highest salary. When the statements are combined, the 15th highest salary can be any positive value. Thus, the two statements combined are INSUFFICIENT. The correct answer is E.”
June 28, 2018
GMATGuruNY posted a reply to GMAT Official Guide 2019 [What is the number of] in the Data Sufficiency forum
“Statements combined: It''s possible that the article is composed of two 5.5 by 8 pages, each with 250 words. It''s possible that the article is composed of three 5.5 by 8 pages, each with 250 words. Since the number of pages can be different values, the two statements combined are INSUFFICIENT. ...”
June 28, 2018
GMATGuruNY posted a reply to A set of pictures of butterflies contains 10 pictures. in the Problem Solving forum
“P(1st picture selected has not already been purchased) = 7/10. (Of the 10 pictures, 3 have already been purchased, so 7 have not.) P(2nd picture selected has not already been purchased) = 6/9. (Of the 9 remaining pictures, 3 have already been purchased, so 6 have not.) To combine these ...”
June 28, 2018
GMATGuruNY posted a reply to Allison and Barbara are part of an 8-member dance troupe. in the Problem Solving forum
“There are 7 people besides Allison. From this pool of 7 people, 3 must be selected to join Allison''s 4-person ensemble. Thus -- from the pool of 7 people -- the probability that Barbara is among the 3 people selected = 3/7. The correct answer is B.”
June 27, 2018
GMATGuruNY posted a reply to The relationship between the cost (c) and time (t) is given in the Data Sufficiency forum
“Original cost = mt+ b. When the time increases by 10, we get: New cost = m(t+10) + b = mt + 10m + b. Thus: Increase in the cost = new cost - original cost = (mt + 10m + b) - (mt + b) = 10m. To determine the increase in the cost, we need to know the value of m. Question stem, rephrased: What ...”
June 27, 2018
GMATGuruNY posted a reply to If An+1=120 + (1/4)An for each positive integer n, and A1=15 in the Problem Solving forum
“A₂ = 120 + (1/4)(A₁) = 120 + (1/4)(150) = 120 + 37.5 = 157.5. A₃ = 120 + (1/4)(A₂) = 120 + (1/4)(157.5) ≈ 120 + 39 = 159. A₄ = 120 + (1/4)(A₃) = 120 + (1/4)(159)... The results above indicate that the terms are increasing in value. Thus, A₁₂ > 159. The correct answer is ...”
June 27, 2018
GMATGuruNY posted a reply to At a fruit store, apples are sold for $4 per pound and orang in the Data Sufficiency forum
“Statement 1: The average price-per-pound for the MIXTURE of apples and oranges (less than $5) is closer to the price-per-pound for apples ($4) than to the price-per-pound for oranges ($6). Implication: Weight-wise, the mixture must be composed mostly of apples. Thus, the answer to the question ...”
June 26, 2018
GMATGuruNY posted a reply to 3^n+3^{n+1}+3^{n+2}/3^{n-2}+3^{n-1}+3^n=? in the Problem Solving forum
“Let n = 3. Plugging n = 3 into the given expression, we get: $$\frac{3^3+3^{3+1}+3^{3+2}}{3^{3-2}+3^{3-1}+3^3}\\$$ $$\frac{3^3+3^4+3^5}{3^1+3^2+3^3}\\$$ $$\frac{3^3(1 + 3 + 3^2)}{3(1+3+3^2)} = 3^2\\$$ When n=3 is plugged into the answers, the result must be 3². Only D is viable. ...”
June 26, 2018
GMATGuruNY posted a reply to Bob and Alice can finish a job together in 3 hours. in the Problem Solving forum
“Let the job = the LCM of the two times = 15 units. Since Bob and Alice together take 3 hours to produce the job, their combined rate = w/t = 15/3 = 5 units per hour. Since Bob on his own takes 5 hours to produce the job, Bob''s rate = w/t = 15/5 = 3 units per hour. Since Bob and Alice together ...”
June 26, 2018
GMATGuruNY posted a reply to Alice and Bob drive the same car. Alice drives the car for 1 in the Problem Solving forum
“The prompt should specify that 1/4 of the trip = 1/4 of the total distance. We can PLUG IN THE ANSWERS, which represent the total distance. When the correct answer is plugged in, the difference between Bob''s distance and Alice''s distance = 40 km. B: 80 km Alice''s distance = (1/4)(80) ...”
June 25, 2018
GMATGuruNY posted a reply to How long did Justin spend driving from Town A to Town B in the Data Sufficiency forum
“Each statement is clearly insufficient on its own. Statements combined: Distance from A to B = (total distance) - (distance from B to C) = 200-100 = 100 miles. The time to travel from A to B can be ANY POSITIVE VALUE. Thus, the total time for the entire trip cannot be determined. INSUFFICIENT. ...”
June 25, 2018
GMATGuruNY posted a reply to Is wp + st > 0? in the Data Sufficiency forum
“Statements combined: Try to satisfy both statements while making wp POSITIVE. Case 1: w=p=s=t=1, with the result that ws + pt = ws + pt = (1*1) + (1*1) = 2 and that wt + ps = (1*1) + (1*1) = 2 In this case, wp + st = (1*1) + (1*1) = 2, so the answer to the question stem is YES. Try to ...”
June 25, 2018
GMATGuruNY posted a reply to If P is an odd integer and (P^2 + Q * R) is an even integer, in the Problem Solving forum
“Let P=1. Case 1: (P² + QR) = 2 Plugging P=1 into the equation above, we get: 1² + QR = 2 QR = 1. If Q=1 and R=1, then B and D are not true. Eliminate B and D. If Q=2 and R=1/2, then A and C is not true. Eliminate A and C. The correct answer is E.”
June 25, 2018
GMATGuruNY posted a reply to What is the value of prime number z? in the Data Sufficiency forum
“Statement 1: z³ < 25 Only one value for z is possible: z = 2, with the result that z³ = 2³ = 8. If z is any other prime number, the value of z³ will exceed 25. Thus, z=2. SUFFICIENT. Statement 2: z² > 1 Here, z can be ANY PRIME NUMBER, since the square of any prime number will be ...”
June 25, 2018
GMATGuruNY posted a reply to A car averages 55 mph for the first 4 hours of a trip in the Problem Solving forum
“Since the car travels at 55 mph for 4 hours, the distance traveled in the first 4 hours = rt = 55*4 = 220 miles. We can PLUG IN THE ANSWERS, which represent the total time. When the correct answer is plugged in, the average speed for the whole trip = 60 mph. B: 8 hours, implying that the last 4 ...”
June 25, 2018
GMATGuruNY posted a reply to If x and y are integers, is 5x + y divisible by 5? in the Data Sufficiency forum
“Statement 1: Case 1: x=5 and y=0 In this case, 5x + y = (5*5) + 0 = 25, so the answer to the question stem is YES. Case 2: x=5 and y=1 In this case, 5x + y = (5*5) + 1 = 26, so the answer to the question stem is NO. Since the answer is YES in Case 1 but NO in Case 2, INSUFFICIENT. Statement ...”
June 25, 2018
GMATGuruNY posted a reply to In a sequence of 40 numbers, each term, except for in the Problem Solving forum
“Since each term is 7 less than the preceding term, the numbers are EVENLY SPACED. For any evenly spaced set, where d is the distance between successive terms: $$a_{n} = a_{1} - (n-1)d$$ In the problem above: a₄₀ = ? a₁ = 281 n = 40 Since each term is 7 less than the preceding term, d ...”
June 25, 2018
GMATGuruNY posted a reply to In a certain class, boys' heights range is 10 inches, and in the Data Sufficiency forum
“Since the range for the boys = 10, we get: tallest boy - shortest boy = 10 tallest boy = 10 + shortest boy. Since the range for the girls = 8, we get: tallest girl - shortest girl = 8 shortest girl = tallest girl - 8. Statement 1: Case 1: tallest girl = 10, shortest boy = 12 Substituting ...”
June 24, 2018
GMATGuruNY posted a reply to With California expected to see severe electricity shortfall in the Sentence Correction forum
“to facilitate X = to make it easier for X to happen. An introductory with-modifier serves to express something that facilitates the action the in the following clause. OA: With California expected to see severe electricity shortfalls and perhaps blackouts on as many as 30 days this summer, the ...”
June 22, 2018
GMATGuruNY posted a reply to A shelf contains hardcover and paperback books, of either in the Data Sufficiency forum
“This is an EITHER/OR group question. Every book is EITHER hardcover OR paperback. Every book is EITHER fiction OR nonfiction. For an EITHER/OR group problem, use a DOUBLE-MATRIX to organize the data. There are two fractions in statement 1: 2/3 and 1/4. Since the product of the denominators = ...”
June 22, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“Let N = 4 kg and D''s time for N kg = 1 hour. Thus, D''s rate = (4 kg)/(1 hour) = 4 kg per hour. Since W produces N/2 kg (2 kg) in twice D''s time for N kg (2 hours), W''s rate = (2 kg)/(2 hours) = 1 kg per hour. Combined rate for D+W = 4+1 = 5 kg per hour. Of every 5 kg produced each hour ...”
June 22, 2018
GMATGuruNY posted a reply to A jar contains exactly 100 marbles; each marble contains in the Data Sufficiency forum
“To calculate the probability of picking at least 2 marbles that contain no blue, we need to know how many of the 100 marbles are part-blue. Question stem, rephrased: How many of the 100 marbles are part-blue? Total marbles = (total part-green) + (total part-red) + (total part-orange) + (total ...”
June 21, 2018
GMATGuruNY posted a reply to When a, b and c are consecutive positive even integers such in the Problem Solving forum
“Test a=6, b=4 and c=2 in the five answer choices. Eliminate any answer choice that does not yield an odd integer. A: (a-c)/2 = (6-2)/2 = 2 --> Eliminate A. B: (a-c)/2 = (2-6)/2 =- 2 --> Eliminate B. C: (a+c)/2 = (6+2)/2 = 4 --> Eliminate C. D: (a+c)/4 = (6+2)/4 = 2 --> Eliminate ...”
June 21, 2018
GMATGuruNY posted a reply to Between 1980 and 1985, Pierre’s investment portfolio in the Data Sufficiency forum
“Let the original investment = $100. Question stem, rephrased: Is the current value greater than $100? Case 1: z=100% Implication: After 1990, Pierre loses 100% of his investment, reducing its value to $0. In this case, x and y are irrelevant. The answer to the rephrased question stem is ...”
June 20, 2018
GMATGuruNY posted a reply to A house cost Ms. Jones C dollars in 1965. Three years in the Problem Solving forum
“Since 25% = 1/4 and 50% = 1/2, let C = the LCM of the two denominators = 4*2 = 8. Since Ms. Jones sells the house for 25% above cost, her profit is equal to 1/4 of the cost: (1/4)(8) = 2. Since she must pay a tax equal to 50% of her profit, the tax = (1/2)(2) = 1. Now plug C=8 into the answers ...”
June 20, 2018
GMATGuruNY posted a reply to If x and y are positive integers such that x^2+y^2 in the Data Sufficiency forum
“Perfect squares less than 18: 1, 4, 9, 16. Perfect cubes less than 18: 1, 8. Options for x²+y³ such that the sum is prime: 1+1 = 2, implying that x=1 and y=1. 4+1 = 5, implying that x=2 and y=1. 9+8 = 17, implying that x=3 and y=2. 16+1 = 17, implying that x=4 and y=1. Both statements ...”
June 20, 2018
GMATGuruNY posted a reply to If the product of 5 different positive integers is less than in the Problem Solving forum
“To MAXIMIZE the largest integer, MINIMIZE the other four integers. Since the integers must be positive and distinct, the smallest possible option for the other four integers is as follows: 1*2*3*4 = 24. We can PLUG IN THE ANSWERS, which represent the value of the largest integer. Of the five ...”
June 20, 2018
GMATGuruNY posted a reply to Aqaba Jordan OG16 in the Sentence Correction forum
“The new bridge will cost $100 million, as the city planner indicates in next year''s budget proposal. Here, indicates is logically preceded by its subject (the city planner). A ruined structure was probably a church, as indicates its eastward orientation and overall plan. Here, the intended ...”
June 19, 2018
GMATGuruNY posted a reply to three-digit code in the Problem Solving forum
“Case 1: 2nd digit is 0 Number of options for the 3rd digit = 9. (Any digit but 0, since the 2nd and 3rd digits cannot both be 0.) Number of options for the 1st digit = 8. (Any digit but 0 or 1.) To combine these options, we multiply: 9*8 = 72. Case 2: 2nd digit is 1 Number of options for the ...”
June 19, 2018
GMATGuruNY posted a reply to If n >2 and n^4-5n^2+4 = 20h, Is h an integer? in the Data Sufficiency forum
“n⁴ - 5n² + 4 = 20h (n²-4)(n²-1) = 20h (n+2)(n-2)(n+1)(n-1) = 20h h will be an integer if the left side is equal to a MULTIPLE OF 20. Question stem, rephrased: Is (n+2)(n-2)(n+1)(n-1) a multiple of 20? Statement 1: Test one case that also satisfies Statement 2. Case 1: n=20, with ...”
June 18, 2018
June 18, 2018
GMATGuruNY posted a reply to gmat prep q in the Problem Solving forum
“Let x=y=1. Then: 2^(x+y)² / 2^(x-y)² = 2^(1+1)² / 2^(1-1)² = 2⁴/2⁰ = 16/1 = 16. The correct answer is D.”
June 18, 2018
GMATGuruNY posted a reply to What is the units digit of 248^20? in the Problem Solving forum
“When 8 is raised to consecutive powers, the unit digit repeat in a CYCLE OF 4: 8¹ --> units digit of 8. 8² --> units digit of 4. (Since the product of the preceding units digit and 8 = 8*8 = 64.) 8³ --> units digit of 2. (Since the product of the preceding units digit and 8 = 4*8 = ...”
June 18, 2018
GMATGuruNY posted a reply to The size of a television screen is given as the length in the Problem Solving forum
“We can save a little time if we know the following: The area of a rhombus with diagonals d₁ and d₂ = (d₁d₂)/2. A square is a rhombus with 4 equal angles. In a square, the two diagonals are equal. Thus, the area of a square with diagonal d = d²/2. a² - b² = (a+b)(a-b). ...”
June 18, 2018
GMATGuruNY posted a reply to A sales associate earns a commission of 8% on in the Data Sufficiency forum
“Initial commission = 8% of 10,000 = $800. Let x = the sales amount after the first $10,000. Additional commission = 10% of sales amount after the first $10,000 = (1/10)x. To calculate the total sales, we need to know the value of x. Question stem, rephrased: What is the value of x? Statement ...”
June 18, 2018
GMATGuruNY posted a reply to If x and y are positive integers and n = 5^x + 7^(y + 3) in the Data Sufficiency forum
“5^x will have a units digit of 5, regardless of the value of x: 5¹ = 5 5² = 25 5³ = 125 In every case, the units digit is 5. To determine the units digit of n, we need to know the units digit of 7^(y+3). Question stem, rephrased: What is the units digit of 7^(y+3)? When 7 is raised to ...”
June 18, 2018
GMATGuruNY posted a reply to If |x - 2| = |x + 3|, x could equal in the Problem Solving forum
“The warning above must be heeded when only one side of an equation is an absolute value. But when BOTH sides of an equation are absolute values, any solution that we derive will be guaranteed to work, so the step above is unnecessary. Since both sides of |x - 2| = |x + 3| are absolute values, we ...”
June 15, 2018
GMATGuruNY posted a reply to A, B, C are three consecutive positive integers (A>B>C in the Problem Solving forum
“Let A=3, B=2 and C=1. 2A + B + 3C = (2*3) + 2 + (3*1) = 11. Now plug A=3 into the answers to see which yields the value in blue. Only E works: 6A-7 = (6*3) - 7 = 18 -7 = 11. The correct answer is E.”
June 15, 2018
GMATGuruNY posted a reply to Is x greater than 3.25? in the Data Sufficiency forum
“Statement 1: 3.2535 ≤ x < 3.2545. When any value in the range above is rounded to the nearest thousandth, the result is 3.254. Since every value in the range above is greater than 3.25, the answer to the question stem is YES. SUFFICIENT. Statement 2: 3.245 ≤ x < 3.255. When any ...”
June 15, 2018
GMATGuruNY posted a reply to If |x - 2| = |x + 3|, x could equal in the Problem Solving forum
“Alternate approach: |a-b| = the distance between a and b. |a+b| = |a-(-b)| = the distance between a and -b. |x - 2| = |x + 3| implies the following: The distance between x and 2 is equal to the distance between x and -3. In other words, x must be HALFWAY BETWEEN -3 AND 2. Halfway between two ...”
June 15, 2018
GMATGuruNY posted a reply to If |x - 2| = |x + 3|, x could equal in the Problem Solving forum
“Case 1: signs unchanged x-2 = x+3 -2 = 3 Since the resulting equation is invalid, Case 1 is not possible. Case 2: signs changed in ONE of the absolute values x-2 = -x-3 2x = -1 x = -1/2. The correct answer is B.”
June 15, 2018
GMATGuruNY posted a reply to Bob is training for a fitness competition. In order to in the Problem Solving forum
“For any set of consecutive integers: count = biggest - smallest + 1. average = (biggest + smallest)/2. sum = (count)(median). Since Bob starts with 25 pull-ups and drops 1 pull-up each round until his final set of 11 pull-ups, the pull-ups are composed of the consecutive integers between ...”
June 15, 2018
GMATGuruNY posted a reply to The price of car A increased by 20 percent over the same in the Data Sufficiency forum
“= Car A increased by 20% = 1.2A. Car B decreased by 20% = 0.8B. The reduced price of car B was what percent of the original price of car A? (reduced B)/(original A) = (0.8B)/A = 0.8(B/A). To answer the question stem, we need to know the value of B/A. Question stem, rephrased: What is the ...”
June 14, 2018
GMATGuruNY posted a reply to Is x = 1? in the Data Sufficiency forum
“Statement 1: Substituting 3⁰ = 1 into the given equation, we get: x = x¹. Case 1: x=0 In this case, the answer to the question stem is NO. Case 2: x=1 In this case, the answer to the question stem is YES. Since the answer is NO in Case 1 but YES in Case 2, INSUFFICIENT. Statement 2: ...”
June 14, 2018
GMATGuruNY posted a reply to x and y are integers such that 4x^2 – y^2 +4x + 4y – 3 = in the Problem Solving forum
“Let x=1. Substituting x=1 into 4x² – y² + 4x + 4y – 3 = 0, we get: 4(1²) – y² + (4*1) + 4y – 3 = 0 4 – y² + 4 + 4y – 3 = 0 – y² + 4y + 5 = 0 y² - 4y - 5 = 0 (y-5)(y+1) = 0 y=5 or y=-1. If y=-1, then A, C and E are not true. If y=5, then D is not true. The correct ...”
June 14, 2018
GMATGuruNY posted a reply to There are 68 children in the cafeteria of a school and in the Problem Solving forum
“One formula for 3 overlapping groups: T = Group 1 + Group 2 + Group 3 - (exactly 2 groups) - 2(all 3 groups) The big idea with overlapping group problems is to SUBTRACT THE OVERLAPS. When we add together everyone in the three groups: Those in exactly 2 of groups are counted twice, so ...”
June 14, 2018
GMATGuruNY posted a reply to GMATPREP:Whales in the Critical Reasoning forum
“The remaining answer choices, negated: B: Among whale fossils that date from later than about fifty million years ago, some are fossils of whale species that drank only fresh water. C: Fossils of whale species that drank fresh water will be found in close proximity to fossils of whale ...”
June 13, 2018
GMATGuruNY posted a reply to During a sale, a clothing store sold each shirt at a price in the Data Sufficiency forum
“Statement 1: Since the average price for the MIXTURE of shirts and sweaters (21) is closer to the sweater price (25) than to the shirt price (15), the store sold more sweaters than shirts. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: Let x = shirts and y = sweaters. ...”
June 13, 2018
GMATGuruNY posted a reply to If n is a positive integer, is 3^4+3^{n+4} divisible by 5? in the Data Sufficiency forum
“3⁴ + 3^(n+4) = 3⁴ + (3^n)(3⁴) = 3⁴(1 + 3^n) = 3⁴(3^n + 1). The expression in blue will be divisible by 5 only if (3^n + 1) is a multiple of 5. Question stem, rephrased: Is (3^n + 1) a multiple of 5? Statement 1: Case 1: n=2, with the result that 3^n + 1 = 3² + 1 = 10. In this ...”
June 13, 2018
GMATGuruNY posted a reply to N is the 36th prime number. N has remainder 1 when it is div in the Problem Solving forum
“The 36th prime number must be ODD. When an odd number is divided by 2, the remainder is 1. The correct answer is C. A remainder must be a nonnegative integer. If this problem were to appear on the GMAT, option A -- a negative integer -- would not be offered as an answer choice.”
June 13, 2018
GMATGuruNY posted a reply to GMAT Prep in the Sentence Correction forum
“The OAs above and E are not analogous. In the OAs above, the omitted verb is a form of to be: Heated oil prices are expected to be higher this year than were = simple past tense form of to be. In E, the omitted verb is NOT a form of to be: Demographers would have to know a great deal more ...”
June 13, 2018
GMATGuruNY posted a reply to When n is divided by 2, 3, 5, 7 and 9, the remainder is 1. W in the Problem Solving forum
“Since n must yield a remainder when divided by 2, n cannot be even. Eliminate A. To yield a remainder of 1 when divided by 9, n must be equal to ONE MORE THAN A MULTIPLE OF 9. Thus, the correct answer choice must be equal to (MULTIPLE OF 9) + 1: B) 211 = 210 + 1 --> Nope. C) 421 = 420 + 1 ...”
June 12, 2018
GMATGuruNY posted a reply to A new cell phone plan is offering pricing based on average in the Data Sufficiency forum
“The prompt should require that q>0, and the question stem should provide a crystal clear referent for this. Also -- if we assume that this refers to Brandon''s 2001 average monthly usage -- the question stem can be answered even without the two statements: Was Brandon''s 2001 average monthly ...”
June 12, 2018
GMATGuruNY posted a reply to tricky challenge question - Is CB || ED? in the Data Sufficiency forum
“Statements combined: Case 1: https://i1262.photobucket.com/albums/ii605/gmatguruny/triangles%20and%20parallelism_case%201_zps4waibbnr.png In this case, ∠B = ∠E and ∠C = ∠D, so CB || ED. Case 2: ...”
June 12, 2018
GMATGuruNY posted a reply to Overlapping sets in the Data Sufficiency forum
“An explanation for the formula below can be found in my post here: https://www.beatthegmat.com/og-13-178-virtual-reality-t111188.html Here is the formula with regard to the prompt above: Total = A + E + N - (AE + AN + EN) - 2(AEN) + None. The prompt gives values for A, E, N, AE, AN, and EN. ...”
June 12, 2018
GMATGuruNY posted a reply to Tricky question- Are x and y integers? in the Data Sufficiency forum
“The derived equation is valid in the following sense: If x and y are values such that their product is an integer and their sum is an integer -- as required by the two statements -- then we can conclude that x²+y² = integer. x=y=√2 is irrelevant because it violates the condition in red. The ...”
June 11, 2018
GMATGuruNY posted a reply to Crowan throws 3 dice and records the product of the numbers in the Problem Solving forum
“Case 1: all fives P(1st roll is 5) = 1/6. P(2nd roll is 5) = 1/6. P(3rd roll is 5) = 1/6. Since we want all of these events to happen together, we multiply the fractions: 1/6 * 1/6 * 1/6 = 1/216. Case 2: two 5''s and one roll that is 1 or 3 P(1st roll is 5) = 1/6. P(2nd roll is 5) = 1/6. ...”
June 11, 2018
GMATGuruNY posted a reply to A lawn care company has five employees, and there are ten in the Problem Solving forum
“The posted problem has been transcribed from the original source -- the book GMAT for Dummies -- incorrectly. In the book, the prompt reads as follows: Number of houses that could be assigned to the first employee = 10. (Any of the 10 houses.) Number of houses that could be assigned to the ...”
June 11, 2018
GMATGuruNY posted a reply to Beth has a collection of 8 boxes of clothing for a charity in the Problem Solving forum
“Let c=2, implying that the average number of pieces per box = 2. Total number of pieces = (number of boxes)(average per box) = 8*2 = 16. When a 12-piece box is removed, the resulting total = 16-12 = 4. When a 22-piece box is added, the resulting total = 4+22 = 26. Resulting average = (total ...”
June 11, 2018
GMATGuruNY posted a reply to Is z an integer? in the Data Sufficiency forum
“Statement 1: Options for 2z: 2z = 2, 4, 6, 8, 10, 12... Dividing every value above by 2, we get the following options for z: z = 1, 2, 3, 4, 5, 6... In every case, z is an integer. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: Options for 4z: 4z = 2, 4, 6, 8, 10, ...”
June 11, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“Let the rate for each child = 1 unit per day. Since each child does half the work of a man, the rate for each man = 2 units per day. Since each woman does double the work of a man, the rate for each woman = 4 units per day. Combined rate for 3 men, 4 women and 6 children = (3*2) + (4*4) + (6*1) ...”
June 11, 2018
GMATGuruNY posted a reply to What is the value of y? in the Data Sufficiency forum
“Statement 1: 3|x² – 4| = y – 2. If x=0, then y=14. If x=2, then y=2. Since y can be different values, INSUFFICIENT. Statement 2: |3 – y| = 11. Solving 3-y = 11 and 3-y = -11, we get: y = -8 or y=14. Since both y = -8 and y=14 are possible, INSUFFICIENT. Statements 1 and 2 ...”
June 11, 2018
GMATGuruNY posted a reply to The sum of 3 consecutive numbers is definitely: in the Problem Solving forum
“Try to show that four of the five answer choices are WRONG. Case 1: -2, -1, 0 Sum = -2 + (-1) + 0 = -3. The resulting sum is not positive, nor is it divisible by 2, 4 or 5. Eliminate A, B, D and E. The correct answer is C. The sum of 3 consecutive integers can be represented and then ...”
June 11, 2018
GMATGuruNY posted a reply to Tricky question- Are x and y integers? in the Data Sufficiency forum
“In DS, each statement is a PREMISE: a fact that cannot be disputed. The premise in Statement 2 is that x+y = integer. Your conclusion -- that x²+y² = integer -- is based upon this premise.. √2 violates this premise and thus is not a valid case when the statements are combined.”
June 10, 2018
GMATGuruNY posted a reply to Tricky question- Are x and y integers? in the Data Sufficiency forum
“Both statements are satisfied by the following cases: Case 1: x=0 and y=0, with the result that xy=0 and x+y=0 In this case, x and y are both integers, so the answer to the question stem is YES. Case 2: x=√2 and y=-√2, with the result that xy=-2 and x+y=0 In this case, x and y and NOT ...”
June 10, 2018
GMATGuruNY posted a reply to In February 1995, Doris Schopper became president in the Sentence Correction forum
“the B: Doris Schopper became president of the international council of Medecins sans Frontieres, the English for “Doctors Without Borders" Here, the English seems to refer to the phrase in red, conveying that the phrase in red = ENGLISH. Not so. The phrase in red is composed of FRENCH ...”
June 9, 2018
GMATGuruNY posted a reply to Abby, Brandon, Cedric, and Deirdre are planning to attend a in the Problem Solving forum
“The total price for 4 people (A, B, C and D) is the same as the total price for 5 people (A, B, C, D and K). Let the total price = the LCM of 4 and 5 = $20. If A, B, C and D pay a total price of $20, the price per ticket = 20/4 = $5. If A, B, C, D and K pay a total price of $20, the price per ...”
June 8, 2018
GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum
“Alternate approach: 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. ...”
June 8, 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 ...”
June 8, 2018
GMATGuruNY posted a reply to Sun and Moon: Difficult one in the Sentence Correction forum
“X and also Y is a valid construction. In this construction, also is used for emphasis: it serves to indicate that Y is somehow notable. An OA in GMATPrep: The organic food industry has organized a successful grassroots campaign -- using websites, public meetings, and also mass mailings. Here, ...”
June 8, 2018
GMATGuruNY posted a reply to Crowan throws 3 dice and records the product of the numbers in the Problem Solving forum
“A odd multiple of 25 will be yielded if the product is composed of two 5''s and an odd integer. Case 1: Crowan rolls three 5''s P(5 on the 1st roll) = 1/6. (Of the 6 possible rolls, one is 5.) P(5 on the 2nd roll) = 1/6. P(5 on the 3rd roll) = 1/6. Since we want all of these events to ...”
June 8, 2018
GMATGuruNY posted a reply to If xyz=x, is x=0? in the Data Sufficiency forum
“Statement 1: Substituting yz=0 into xyz = x, we get: x*0 = x 0 = x. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: Substituting xy=0 into xyz = x, we get: 0*z = x 0 = x. Thus, the answer to the question stem is YES. SUFFICIENT. The correct answer is D.”
June 8, 2018
GMATGuruNY posted a reply to An ant is clinging to one corner of a box in the shape of a in the Problem Solving forum
“https://s22.postimg.cc/60lk6c44d/Cubo.png Let the initial vertex = A, implying that the ant must travel to G. Let''s divide the journey into 3 stages and count the number of options for each stage. First stage; Since the ant can travel from A to B, D, or E, the number of options for the ...”
June 8, 2018
GMATGuruNY posted a reply to Speed/Distance in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the initial speed. When the correct answer is plugged in, increasing the speed by 10 kph will enable the cyclist to travel 25 km in 5 fewer minutes. Since the increase in the speed and the total distance are both multiples of 10, the correct answer is ...”
June 8, 2018
GMATGuruNY posted a reply to The ACME company manufactured x brooms per month from in the Problem Solving forum
“Let x=2, implying that 2 brooms are manufactured each month January through April.. Since January through April = 4 months, the number of brooms manufactured = 4*2 = 8. For the rest of the year, the number brooms sold each month = x/2 = 2/2 = 1. Implication: Starting in May, ACME''s stock of ...”
June 7, 2018
GMATGuruNY posted a reply to One gallon of soft drink is made of 40% orange juice and 60% in the Problem Solving forum
“If 40% juice and 100% juice are combined in EQUAL AMOUNTS, the resulting juice concentration will be the AVERAGE of the two percents: (40+100)/2 = 70. Thus, if 1 gallon of soft drink (which is 40% juice) is combined with 1 gallon of pure juice (which is 100% juice), the resulting mixture will be ...”
June 7, 2018
GMATGuruNY posted a reply to If 5 percent of the personnel stationed at army base M are o in the Data Sufficiency forum
“While you seem to have arrived at the correct answer, your approach might prove problematic for other problems. For example: Your first equation: (5/100)(M + F) = officers Here, F = the total number of females. For this reason, a stand-alone F should represent the total number of females in ...”
June 7, 2018
GMATGuruNY posted a reply to In the x-y plane, does the parabola y=ax^2+bx+c have x-inter in the Data Sufficiency forum
“For any parabola of the form y = ax² + bx + c, the DISCRIMINANT is equal to b² - 4ac. If the discriminant is positive, then the parabola has two x-intercepts. If the discriminant is equal to 0, then the parabola has one x-intercept. If the discriminant is negative, then the parabola has no ...”
June 7, 2018
GMATGuruNY posted a reply to How many integers between 50 and 100, inclusive, are divisi in the Problem Solving forum
“Total integers = (multiples of 2) + (multiples of 3) - (multiples of both 2 and 3). For any evenly spaced set: Count = (biggest - smallest)/increment + 1. The INCREMENT is the difference between one value and the next. Multiples of 2 between 50 and 100, inclusive: Smallest = 50. Biggest = ...”
June 7, 2018
GMATGuruNY posted a reply to Which of the following best completes the passage below in the Critical Reasoning forum
“Premise: 2/5 of the surveyed job applicants admitted to being dishonest (implying that 3/5 of the surveyed applicants claimed to be totally honest). Conclusion: The survey may underestimate the proportion of job applicants who are dishonest. A: Some dishonest people taking the survey might have ...”
June 6, 2018
GMATGuruNY posted a reply to Speed/Distance in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the distance traveled at 4 kph. Since all of the values in the problem are INTEGERS, the correct answer is almost certain to be a multiple of 4. Of the 5 options, only C is a multiple of 4. When the correct answer is plugged in, the total time = 9 ...”
June 6, 2018
GMATGuruNY posted a reply to At a certain organisation, the number of in the Problem Solving forum
“This is a MIXTURE problem. Percent change for men = +12%. Percent change for women = -6%. Percent change for the MIXTURE of men and women = +1.2%. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Let M = men and W = women. Step 1: Plot the 3 ...”
June 6, 2018
GMATGuruNY posted a reply to Is a < 2? in the Data Sufficiency forum
“The answer to the question stem can be NO -- implying that a≥2 -- only if a is positive. Thus, when we evaluate the statements, we need consider only POSITIVE values for a. Statement 1: In the xy-plane, the point (a, 1) lies inside the circle whose equation is x^2 + y^2 = 3. Every point (x, ...”
June 6, 2018
GMATGuruNY posted a reply to How many of the positive divisors of 120 are also multiples in the Problem Solving forum
“120 = 4*30 = 4 * (2*3*5). To form a multiple of 4 that divides evenly into 120 but is not equal to 120, we must combine 4 with up to two of the factors in blue: 4 4*2 4*3 4*5 4*2*3 4*2*5 4*3*5 Total options = 7. The correct answer is D.”
June 6, 2018
GMATGuruNY posted a reply to A bakery sells white bread for certain price and rye in the Data Sufficiency forum
“What is the value of 2W + 3R? Statement 1: 2W + 2R = 880. No ways to determine the value of 2W + 3R. INSUFFICIENT. Statement 2: 4W + 6R = 2220 2R + 3W = 1110. SUFFICIENT. The correct answer is B.”
June 6, 2018
GMATGuruNY posted a reply to A rectangular tiled patio is composed of 70 square tiles. in the Problem Solving forum
“Let R = the number of rows and C = the number of columns. Total number of tiles = RC. Since there are 70 tiles, we get: 70 = RC. We can PLUG IN THE ANSWERS, which represent the value of R. The equation in blue indicates that the value of R must be a FACTOR OF 70. Of the five answer ...”
June 6, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“Since 16 men working for 12 days are the equivalent of 24 children working for 18 days, we get: (16m)(12) = (24c)(18) 4m = 9c m = (9/4)c. Let the rate for each child = 4 units per day, implying that the rate for each man = (9/4)(4) = 9 units per day. Since 24 children complete the job in 18 ...”
June 5, 2018
GMATGuruNY posted a reply to Analysts blamed May’s sluggish retail in the Sentence Correction forum
“Generally, COMMA + VERBing serves to modify the nearest preceding action and the agent of that action. Analysts blamed May’s sluggish retail sales on unexciting merchandise as well as the weather, which was colder and wetter than usual in some regions, slowing sales of barbecue grills. Here, the ...”
June 5, 2018
GMATGuruNY posted a reply to Is xy<6? in the Data Sufficiency forum
“Statements combined: Case 1: x=0 and y=0 In this case, xy < 6. Case 2: x=-10 and y=-10 in this case, xy > 6. Since the answer is YES in Case 1 but NO in Case 2, the two statements combined are INSUFFICIENT. The correct answer is E.”
June 5, 2018
GMATGuruNY posted a reply to If a triangle has one side of 3 cm and another side in the Data Sufficiency forum
“Statement 1: Case 1: The triangle is 3-4-5 In this case, the third side -- the hypotenuse -- has a length of 5. Case 2: hypotenuse = 4 In this case, a² + 3² = 4⁴. Thus, the length of the third side -- the value of a --- will NOT be 5. Since the third side can have different lengths, ...”
June 5, 2018
GMATGuruNY posted a reply to If 2x = 3y = 10, then 12xy = ? in the Problem Solving forum
“Since 2x=10 and 3y=10, we get: (2x)(3y) = 10*10 6xy = 100 12xy = 200. The correct answer is B.”
June 5, 2018
GMATGuruNY posted a reply to Is xy<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, allowing us to SQUARE the inequality: (|x+y|)² < (|x| + |y|)² x² + y² + 2xy < x² + y² + 2|x||y| 2xy < ...”
June 5, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“Let the job = 40 units. Since A takes 10 days to complete the job, A''s rate = w/t = 40/10 = 4 units per day. Since B takes 20 days to complete the job, B''s rate = w/t = 40/20 = 2 units per day. Since C takes 40 days to complete the job, C''s rate = w/t = 40/40 = 1 unit per day. Work completed ...”
June 5, 2018
GMATGuruNY posted a reply to progressions 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 numbers between 10 and 300, inclusive: Here, the integers are EVEN, so the increment = 2. Count ...”
June 5, 2018
GMATGuruNY posted a reply to There are x teams and each team plays each other once in the Problem Solving forum
“Each game is played by a PAIR OF TEAMS. Since every team must play every other team exactly once, the total number of games is to equal to the number of possible pairs that can be formed from the x teams. We can PLUG IN THE ANSWERS, which represent the value of x. When the correct answer is ...”
June 4, 2018
GMATGuruNY posted a reply to When x and n are positive integers, if x^{2n}>(3x)^n, whi in the Problem Solving forum
“x^(2n) > (3x)^n (x^n)² > (3^n)(x^n) (x^n)(x^n) > (3^x)(x^n) x^n > 3^n. Since each side of the resulting inequality has the same exponent, the left side will be greater than the right side only if x > 3. The correct answer is A.”
June 4, 2018
GMATGuruNY posted a reply to 30^20 – 20^20 is divisible by all 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. 3²⁰ - 2²⁰ = (multiple of 3) - (non-multiple of 3) = non-multiple of 3. Since 3²⁰ - 2²⁰ is not divisible by 3, it cannot be divisible by a multiple of 3 such as 60. ...”
June 4, 2018
GMATGuruNY posted a reply to Abby and Bobby type at constant rates of 80 words per minute in the Problem Solving forum
“For Abby to CATCH-UP by 600 words and type AHEAD 200 words, she must type a total of 800 more words than Charlie. When people compete, SUBTRACT THEIR RATES. Since Bobby types 60 words per minute, and Abby types 80 words per minute, every minute Abby types 20 more words than Bobby -- the DIFFERENCE ...”
June 4, 2018
GMATGuruNY posted a reply to The nephew of Pliny the Elder wrote the only eyewitness in the Sentence Correction forum
“Correct! Correct!”
June 4, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“Let the job = 15 units. Since A and B take 5 days to produce the 15-unit job, A+B = w/t = 15/5 = 3 units per day. Thus: A+B = 3. Since 2A and (1/3)B take 3 days to produce the 15-unit job, 2A + (1/3)B = w/t = 15/3 = 5 units per day. Thus: 2A + (1/3)B = 5 6A + B = 15. Subtracting the ...”
June 3, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent B''s time to produce the entire job alone. Since B takes 44 days to produce part of the job, B''s time to produce the entire job must be more than 44 days. Eliminate A and B. When the correct answer is plugged in, the time for B to complete the job ...”
June 3, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“Let Q = 1 liter per turn. Since P has 3 times the capacity of Q, P = 3 liters per turn. Since P takes 60 3-liter turns to fill the drum, the drum = 60*3 = 180 liters. Since P = 3 liters per turn and Q = 1 liter per turn, the number of turns for P and Q together to fill the 180-liter drum = ...”
June 3, 2018
GMATGuruNY posted a reply to work in the Problem Solving forum
“Let the tank = 6 liters. Since one tap takes 6 hours to fill the 6-liter tank, the rate for each tap = w/t = 6/6 = 1 liter per hour. Time for one tap to fill half the 6-liter tank = w/r = 3/1 = 3 hours. After 3 additional taps are opened, the combined rate for 4 taps = 4 liters per hour. Time ...”
June 3, 2018
GMATGuruNY posted a reply to In numerous factories, automated equipment is in the Critical Reasoning forum
“Premise: In numerous factories, automated equipment is replacing employees. Conclusion: Factories that fire employees will eventually pay...through a heavier tax burden and unemployment insurance fees. C: Most employees that have been replaced by automated equipment are unskilled workers and ...”
June 3, 2018
GMATGuruNY posted a reply to Released the first Friday of every month and covering the in the Sentence Correction forum
“A and B: amount of new jobs Here, amount cannot serve to refer to a countable noun such as jobs. Eliminate A and B. D: the...report disclosed the number of new jobs that are created E: the...report disclosed the number of new jobs that have been created Here, it is not possible that the ...”
June 3, 2018
GMATGuruNY posted a reply to Last year the price per share of Stock X increased by k % in the Problem Solving forum
“Original ratio: Let the original price = 1 and the original earnings = 1. Resulting ratio: price/earnings = 1/1 = 1. New ratio: Let k=200 and m=100. Since the price increases by k=200%, the new price = 1 + (200/100)(100) = 3. Since the earnings increase by m=100%, the new earnings = ...”
June 3, 2018
GMATGuruNY posted a reply to In the sequence a_1, a_2, . . . , a_n each term in the Problem Solving forum
“For any evenly spaced set: average = median. sum = (count)(average). a₁ + a₁₁ + a₂₁ = 99. In the given sequence, the difference between one term and the next = c. Implication: {a₁, a₁₁, a₂₁} constitutes an evenly spaced set because the difference between one term and the ...”
June 3, 2018
GMATGuruNY posted a reply to Set X contains 10 consecutive integers. If the sum of the in the Problem Solving forum
“For any set of consecutive integers: average = median. sum = (count)(median). Since the sum of the 5 smallest integers = 265, we get: 265 = (5)(median) median = 265/5 = 53. Thus, the 5 smallest integers are 51, 52, 53, 54, and 55, implying that the 5 largest integers are 56, 57, 58, 59, ...”
June 2, 2018
GMATGuruNY posted a reply to The distance between West-Town to East-Town is 15 kilometers in the Problem Solving forum
“Since the two birds travel toward each other, they WORK TOGETHER to cover the 15 kilometers between them. When elements work together, ADD THEIR RATES. The combined rate for the two birds = 4+1 = 5 kpm. Of every 5 kilometers traveled by the two birds working together, 4 kilometers are traveled ...”
June 2, 2018
GMATGuruNY posted a reply to The flow of water through a drainage pipe was monitored for in the Problem Solving forum
“Let F = the first hour and T = the third hour. Since the second-hour rate is 50% faster than the first-hour rate, the second-hour rate (15 gallons) is 150% of the first-hour rate: 15 = (150/100)F 15 = (3/2)F 30 = 3F F = 10 gallons. Since 25% more water flows during the third hour than ...”
June 2, 2018
GMATGuruNY posted a reply to Today Jim is twice as old as Fred, and Sam is 2 years in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent Jim''s current age. When the correct answer is plugged in, Jim''s age four years ago will be 4 times Sam''s age four years ago. B: J=12 Since Jim is twice as old as Fred, F=6. Since Sam is 2 years younger than Fred, S=4. Four years ago, J = 12-4 = 8 ...”
June 1, 2018
GMATGuruNY posted a reply to A set X; {a1, a2, a3, a4, a5} with non-zero elements have in the Problem Solving forum
“Let Set X = {1, 2, 3, 4, 5} Since the set is evenly spaced, the average is equal to the median: M = 3. Since Set Y = {A₁-1, A₂-2, aA₃-3, A₄+5, A₅+1}, we get: Set Y = (0, 0, 0, 9, 6}. Mean of Set Y = (0+0+0+9+6)/5 = 3. As illustrated by the values in blue, the mean of Set Y = M. ...”
June 1, 2018
GMATGuruNY posted a reply to Is x an even integer? in the Data Sufficiency forum
“Statement 1 indicates that x is a perfect square: 1, 4, 9, 16, 25, 36, 49, 64... Statement 2 indicates that x is a perfect cube: 1, 8, 27, 64... When the statements are combined, x must be equal to a value contained in both lists. Thus: It''s possible that x=1. It''s possible that x=64. ...”
June 1, 2018
GMATGuruNY posted a reply to In the sequence {A_n}, A1=1 and An = 3An-1 + 1 for all posit in the Problem Solving forum
“A₁ = 1. A₂ = 3A₁ + 1 = (3*1) + 1 = 4. A₃ = 3A₂ + 1 = (3*4) + 1 = 13. A₄ = 3A₃ + 1 = (3*13) + 1 = 40. A₅ = 3A₄ + 1 = (3*40) + 1 = 121. A₆ = 3A₅ + 1 = (3*121) + 1 = 364. The results above indicate that the units digits repeat in a CYCLE OF 4: 1, 4, 3, 0...1, 4, 3, 0... ...”
June 1, 2018
GMATGuruNY posted a reply to The nephew of Pliny the Elder wrote the only eyewitness in the Sentence Correction forum
“The nearest eligible verb should be the main verb of the following clause. The blue statement above refers to answer choices that are incorrect because the nearest eligible verb is NOT the main verb of the following clause.”
June 1, 2018
GMATGuruNY posted a reply to ratios in the Problem Solving forum
“Container 1 : Container 2 : Container 3 = 3:4:5. In Container 1, M:W = 4:1, implying that water constitutes 1/5 of Container 1. In Container 2, M:W = 3:1, implying that water constitutes 1/4 of Container 2. In Container 3, M:W = 5:2, implying that water constitutes 2/7 of Container 3. The ...”
June 1, 2018
GMATGuruNY posted a reply to In a high school debating team consisting of 2 freshmen, in the Problem Solving forum
“Two of the four grades must be selected to represent the team at the championship. Because each grade on the debate team offers the same number of students -- 2 students per grade -- the probability of picking each grade is the same. Thus, the problem can be rephrased as follows: What is the ...”
May 31, 2018
GMATGuruNY posted a reply to J = x rounded to the nearest TENTH, and K = x rounded to the in the Problem Solving forum
“Since J = x rounded to the nearest tenth, J = 0.a (where a is a digit 0-9). Since K = x rounded to the nearest thousandth, K = 0.bcd (where b, c and d are any digits 0-9). The value of K implies that J-K can have at most three digits to the right of the decimal. Eliminate B, D and E. To ...”
May 31, 2018
GMATGuruNY posted a reply to profit and loss in the Problem Solving forum
“At a price of $10 each, 100 seats are sold. For every $2 increase in the price per seat, 5 fewer seats will be sold. The following options are implied: 12*95 = 12(100-5) = 1200-60 = 1140. 14*90 = 1260. 16*85 = 16(80+5) = 1280+80 = 1360. In the blue option, $1360 in revenue is yielded by a seat ...”
May 31, 2018
GMATGuruNY posted a reply to ratios in the Problem Solving forum
“Day crew: Let the number of workers = 5. Let the number of boxes loaded by each worker = 4. Total number of boxes loaded = 5*4 = 20. Night crew: Since the night crew has 4/5 as many workers as the day crew, the number of workers on the night crew = (4/5)5 = 4. Since each worker on the ...”
May 31, 2018
GMATGuruNY posted a reply to ratios in the Data Sufficiency forum
“Statement 1: Among the blue-eyed wolves, the ratio of grey coats to white coats is 4:3. Since (blue-eyed grey):(blue-eyed white) = 4:3 -- and 4+3 = 7 -- the total number of blue-eyed wolves must be a MULTIPLE OF 7. Since there are MORE THAN 3 blue-eyed white wolves, the least possible case is as ...”
May 31, 2018
GMATGuruNY posted a reply to In the sequence {An}, A1=1 and An=An-1+ …. +A1. What is th in the Problem Solving forum
“To avoid confusion, the GMAT would probably rephrase the prompt along the following lines: Each term after the first two terms is equal to the sum of the preceding terms: A₃ = 2 + 1 = 3. A₄ = 3 + 2 + 1 = 6. A₅ = 6 + 3 + 2 + 1 = 12. A₆ = 12 + 6 + 3 + 2 + 1 = 24. The results ...”
May 31, 2018
GMATGuruNY posted a reply to At a certain library, 12 students borrowed a total of in the Problem Solving forum
“Statement I: 9 students borrow 6 books each Let the other 3 students be A, B and C. Since 9 students borrow 6 books each, the list of borrowed books is as follows: A, B, C, 6, 6, 6, 6, 6, 6, 6, 6, 6, 6. Books borrowed by A+B+C = (total books borrowed) - (books borrowed by the 9 students in blue) ...”
May 31, 2018
GMATGuruNY posted a reply to Jack gave 20% discount on sale of 15 toys & generated in the Problem Solving forum
“First day: $600 in revenue yields a profit of 25% = 1/4. Implication: The $600 in revenue is equal to 5/4 of the cost of 15 toys: 600 = (5/4)C C = 480. Thus: Profit for the 15 toys on the first day = (revenue) - (cost) = 600-480 = 120. Second day: The $600 first-day revenue includes a ...”
May 31, 2018
GMATGuruNY posted a reply to John spent 72% of his budget on fruits (including apples) in the Problem Solving forum
“Let John''s budget = $100. Since 72% of the budget is spent on fruit, the amount spent on fruit = $72. Since 54% of the budget is spent on apples, the amount spent on apples = $54. What percent of the money spent on fruit was not spent on apples? Of the $72 spent on fruit, the amount not spent ...”
May 31, 2018
GMATGuruNY posted a reply to The price of onions increases by 25%, by what percent should in the Problem Solving forum
“Let the original price per onion = $4, implying that the price per onion after a 25% increase = $4 + (25% of 4) = 4 + 1 = $5. Let the total amount spent in each case = the LCM of the two prices = $20. Number of onions purchased at the original $4 price = (total spent)/(price per onion) = 20/4 = ...”
May 30, 2018
GMATGuruNY posted a reply to In the initial planning stages, the condominium corporation in the Sentence Correction forum
“In B and C, their (plural) does not agree with corporation (singular). Eliminate B and C. D: only were taken...not those Here, were taken (verb) is illogically contrasted with those (pronoun). Eliminate D. E: only taken...not those Here, taken (participle) is illogically contrasted with ...”
May 30, 2018
GMATGuruNY posted a reply to In the last twenty years, despite the chauvinism of European in the Sentence Correction forum
“In A and B, the present tense verbs are respected and are becoming cannot serve to express an action performed IN THE LAST TWENTY YEARS. Eliminate A and B. In C, California wines (subject) lacks a verb. The result is an incomplete sentence. Eliminate C. E implies the following: California ...”
May 30, 2018
GMATGuruNY posted a reply to Challenge question: On the x-y coordinate plane, lines j and in the Data Sufficiency forum
“Statement 1: Substituting x=1 and y=-3 into the equations for lines j and k, we get: Line j: b(1) - a(-3) = 5 b + 3a = 5. Line k: 2b(1) - 3a(-3) = -5 2b + 9a = -5. The two equations in green can be solved for a and b. Thus, the value of a+b can be determined. SUFFICIENT. Statement 2: a ...”
May 30, 2018
GMATGuruNY posted a reply to If the distances between each pair of consecutive ticks are in the Problem Solving forum
“- Since the ticks are equally spaced, the difference between x and 2¹¹ is equal to the the difference between 2¹¹ and 2¹⁰: x - 2¹¹ = 2¹¹ - 2¹⁰ x = 2¹¹ + 2¹¹ - 2¹⁰ x = 2¹⁰(2 + 2 - 1) x = 2¹⁰(3). The correct answer is B.”
May 30, 2018
GMATGuruNY posted a reply to If 5 percent of the personnel stationed at army base M are o in the Data Sufficiency forum
“Statements combined: Case 1: Total number of personnel = 5,200 Case 2: Total number of personnel = 5,200,000 Clearly, the number of non-officers in Case 2 will be greater than the number of non-officers in Case 1. Since the number of non-officers can be different values, the two statements ...”
May 29, 2018
GMATGuruNY posted a reply to If each of the 4 circles above has radius 1, what in the Problem Solving forum
“https://s22.postimg.cc/aompuia8t/four_circles.png Area of the blue square above = s² = 2² = 4. Area of each circle = πr² = π(1²) = π. Each unshaded portion in the blue square constitutes 1/4 of a circle. Thus, the 4 unshaded portions combined constitute one full circle. Shaded portion ...”
May 29, 2018
GMATGuruNY posted a reply to How many 4-digit integers have the form abcd, where b is eve in the Problem Solving forum
“The sum in red is incorrect. Correct: 900+540+180 = 1620. Could you please correct the typo in your post?”
May 29, 2018
GMATGuruNY posted a reply to The Metropolitan Cooking Academy surveyed in the Critical Reasoning forum
“sus- means beneath. -pect means look. to suspect = to LOOK BENEATH something and render a BELIEF about it. John suspects that the race will be difficult. Conveyed meaning: Having "looked beneath" the race, John BELIEVES that it will be difficult. TO SUSPECT + THAT-CLAUSE implies ...”
May 29, 2018
GMATGuruNY posted a reply to The operation # is defined to be multiplication. Which of th in the Problem Solving forum
“Ⅰ. x#1=x If we replace # with multiplication, we get: x*1 = x x = x. Since the resulting equation is valid, Statement I must be true. Eliminate B and C, which do not include Statement I. Ⅲ. x#y=y#x If we replace # with multiplication, we get: x*y = y*x xy = yx. Since the ...”
May 29, 2018
GMATGuruNY posted a reply to p, q, x, and y are positive integers. If p^mq^n=72, what is in the Data Sufficiency forum
“I believe that the prompt has a typo and should read as follows: Both statements are satisfied by the following cases: Case 1: p=2, m=3, q=3 and n=2, with the result that m>n, mn=3*2=6, and (p^m)(q^n) = 2³3² = 72 In this case, p+q = 2+3 = 5. Case 2: p=1, m=6, q=72 and n=1, with the ...”
May 29, 2018
GMATGuruNY posted a reply to If a set consists of all positive digits less than or in the Problem Solving forum
“The MODE of a set is the number that appears the most often. Positive digits less than or equal to 3: 1, 2, 3. Squares of these digits: 1, 4, 9. Resulting set when the two lists above are combined: 1, 1, 2, 3, 4, 9. In the resulting set, the number that appears the most often is 1. The ...”
May 28, 2018
GMATGuruNY posted a reply to One robot builds a robot in 1 hour, another one builds a in the Problem Solving forum
“Let each robot = 2 units. Since a faster robot takes 1 hour to produce a 2-unit robot, the rate for a faster robot = w/t = 2/1 = 2 units per hour. Since a slower robot takes 1 hour to produce a 2-unit robot, the rate for a slower robot = w/t = 2/2 = 1 unit per hour. Each additional robot produced ...”
May 28, 2018
GMATGuruNY posted a reply to Are x and y both positive? in the Data Sufficiency forum
“Statement 1: 2x-2y = 1. 2(x-y) = 1. x-y = 1/2. x = y + 1/2. It''s possible that y=1/2 and x=1. It''s possible that y=0 and x=1/2. Since in the first case x and y are both positive and in the second case x and y are not both positive, insufficient. Statement 2: x/y > 1. It''s possible ...”
May 28, 2018
GMATGuruNY posted a reply to A soda machine sells both bottles and cans, and no other in the Problem Solving forum
“Price per bottle = 150 cents. Price per can = 75 cents. Average price for the MIXTURE of bottles and cans = (total revenue)/(total number of beverages) = (315 dollars)/(250 beverages) = 63/50 dollars = 126/100 dollars = 126 cents. To determine the ratio of bottles to cans, we can use ...”
May 28, 2018
May 28, 2018
GMATGuruNY posted a reply to South Korea has witnessed the world's most dramatic growth in the Sentence Correction forum
“A: from conversions rather than the population Here, CONVERSIONS are illogically compared to THE POPULATION. Eliminate A. C: conversions instead of the...increasing Here, CONVERSIONS are illogically compared to THE INCREASING. D and E: Church membership is expanding by 6.6 percent a year, ...”
May 26, 2018
GMATGuruNY posted a reply to A lecture course consists of 595 students. The students are in the Problem Solving forum
“Number of discussion sections = (total number of students)/(number of students per section). section. Since the total number of students = 595, the number of students per section must be a FACTOR OF 595. The question stem asks for a value that CANNOT be the number of students per classroom. ...”
May 26, 2018
GMATGuruNY posted a reply to There are 8 disks in a container that are numbered 23, 24, in the Problem Solving forum
“P = (good outcomes)/(all possible outcomes). All possible outcomes: From the 8 numbers, the number of ways to choose 4 = 8C4 = (8*7*6*5)/(4*3*2*1) = 70. Good outcomes: For 27 to be the median of the 5 numbers, two of the 4 numbers selected must be LESS THAN 27, while the other two must be ...”
May 26, 2018
GMATGuruNY posted a reply to Mrs. Jones divided $120 evenly among her children. Tom, the in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total number of children. When the correct answer is plugged in, Tom''s resulting amount = $12. B: 5 children, implying that the original share per child = 120/5 = 24 After Tom gives $6 to each of his 4 siblings, Tom''s resulting amount = 24 - ...”
May 25, 2018
GMATGuruNY posted a reply to Which of the following leads to the correct mathematical in the Problem Solving forum
“This problem does indeed require that we count the number of possible arrangements. BANANA = 6 letters. The number of ways to arrange 6 distinct elements = 6!. But the elements here are not all distinct. There are 3 identical A''s and 2 identical N''s. When an arrangement includes ...”
May 25, 2018
GMATGuruNY posted a reply to What is the remainder when 7^100 is divided by 50? in the Problem Solving forum
“If the last two digits of an integer form a value less than 50, then dividing the integer by 50 will yield a remainder equal to the last 2 digits of the integer: 121/50 = 2 R21 9044/50 = 180 R44 25038/50 = 500 R38. Examine the last two digits for small powers of 7 and look for a PATTERN: 7¹ ...”
May 25, 2018
GMATGuruNY posted a reply to To understand why some people are incapable to learn in the Sentence Correction forum
“A and B: some people are incapable to learn The portion in red is unidiomatic. Incorrect: X is incapable to do Y Correct: X is incapable OF doing Y Eliminate A and B. C: To understand...the brains of 96 convicts Here, to understand seems to refer to the brains, implying that THE BRAINS are ...”
May 25, 2018
GMATGuruNY posted a reply to The alarm of a certain clock rings every 15 minutes. If the in the Problem Solving forum
“After the first ring at 12:15, 23 additional rings are required to yield a total of 24 rings. Since the clock rings every 1/4 hour, and 23 additional rings are required, the total time needed for 23 additional rings = (¼)(23) = 5 ¾ hours = 5 hours, 45 minutes. Thus: 24th ring = (12:15) + (5:45) ...”
May 25, 2018
GMATGuruNY posted a reply to Let abcd be a general four-digit number and all the in the Problem Solving forum
“Step 1: Choose 3 digits Since 0 < d ≤ 9, a, b and c must be composed of 3 digits with a nonzero sum less than or equal to 9: 1, 2, 3 --> d = 1+2+3 = 6 1, 2, 4 --> d = 1+2+4 = 7 1, 2, 5 --> d = 1+2+5 = 8 1, 2, 6 --> d = 1+2+6 = 9 1, 3, 4 --> d = 1+3+4 = 8 1, 3, 5 --> d ...”
May 25, 2018
GMATGuruNY posted a reply to Three men and 2 women will present 5 consecutive speeches in the Problem Solving forum
“P(at least 2 men speak consecutively) = 1 - P(no men speak consecutively). For no men to speak consecutively, the order of the speeches must be as follows: man-woman-man-woman-man. P(1st speaker is a man) = 3/5. (Of the 5 speakers, 3 are men.) P(2nd speaker is a woman) = 2/4. (Of the 4 ...”
May 24, 2018
GMATGuruNY posted a reply to By approximately what percent did the sale of nonfiction in the Problem Solving forum
“According to the undashed line on the chart: Nonfiction in 1984 = 40%. Nonfiction in 1987 ≈ 58%. Thus: Percent increase from 40 to 58 = (difference/original) * 100 = (18/40) * 100 = 45%. The correct answer is A.”
May 24, 2018
GMATGuruNY posted a reply to It has been estimated that the annual cost to the United in the Sentence Correction forum
“In A, B and D, annual and a year are redundant. Eliminate A, B and D. E: It has been estimated...because of illiteracy. Here, a reader could construe that illiteracy CAUSES 20 billion a year to be estimated. Not the intended meaning. Eliminate E. The correct answer is C.”
May 24, 2018
GMATGuruNY posted a reply to The median of 5 numbers is 50, and their range is 40. If the in the Problem Solving forum
“I suspect that the question stem has a typo and should read as follows: The median of 5 numbers is 50. The median of the 3 smallest numbers is 40. The 5 numbers are as follows: __ 40 __ 50 __ __ Test whether I, II and III could be the range of the 3 largest numbers. If the ...”
May 24, 2018
GMATGuruNY posted a reply to How many 4-digit integers have the form abcd, where b is eve in the Problem Solving forum
“Case 1: b=0, implying that d ≥ 0 Number of options for d = 10. (Any of the 10 digits.) Number of options for a = 9. (Any digit 1-9.) Number of options for c = 10. (Any of the 10 digits.) To combine the options above, we multiply: 10*9*10 = 900. Case 2: b=2, implying that d ≥ 4 Number of ...”
May 24, 2018
GMATGuruNY posted a reply to When the digits of two-digit, positive integer M are reverse in the Data Sufficiency forum
“Let T = the TENS digit of M and U = the nonzero UNITS digit of M. Then: M = 10T + U. Since the digits in N are reversed, N = 10U + T. Resulting difference: M-N = (10T + U) - (10U + T) = 9T - 9U = 9(T-U). Since the greatest possible value of T-U = 9-1 = 8, M-N must be a MULTIPLE OF 9 NO ...”
May 24, 2018
GMATGuruNY posted a reply to If a and b are positive integers in the Data Sufficiency forum
“It is a good idea to know the following: 1/11 = 0.090909... Thus: 9/11 = 9(0.090909...) = 0.818181...”
May 23, 2018
GMATGuruNY posted a reply to At 8am on Thursday, two workers, A and B, each start working in the Problem Solving forum
“Worker A takes two 8-hour days to produce a lamp, for a total of 16 hours. Since Worker B finishes sometime Friday morning, B takes between 8 and 12 hours to produce a lamp. Let each lamp = 48 units. A''s rate = w/t = 48/16 = 3 unit per hour. If B takes 8 hours to produce a lamp, B''s rate = ...”
May 23, 2018
GMATGuruNY posted a reply to Is k^2 odd? in the Data Sufficiency forum
“The median for an EVEN NUMBER of consecutive integers will always be a NON-INTEGER: 1, 2 --> median = 1.5 1, 2, 3, 4 --> median = 2.5. 1, 2, 3, 4, 5, 6 --> median = 3.5. The median for an ODD NUMBER of consecutive integers will always be an INTEGER: 1, 2, 3 --> median = 2. 1, 2, ...”
May 23, 2018
GMATGuruNY posted a reply to Is x - y > 0? in the Data Sufficiency forum
“Question stem, rephrased: Is x > y? Statement 1: Case 1: y=0, implying that x > |0| and thus x > 0 Case 2: y=1, implying that x > |1| and thus x > 1 Case 3: y=-1, implying that x > |-1| and thus x > 1 Case 4: y=10, implying that x > |10| and thus x > 10 Case 5: ...”
May 23, 2018
GMATGuruNY posted a reply to If x and y are positive integers, does x/y = 7/9? in the Data Sufficiency forum
“Statement 1: Test whether it''s possible that x/y = 7/9 when x=103: 103/y = 7/9 7y = 103*9 y = (103*9)/7 = noninteger. Since y must be a positive integer, it is not possible that x/y = 7/9. Thus, the answer to the question stem is NO. SUFFICIENT. To compare fractions: 1. Multiply the ...”
May 23, 2018
GMATGuruNY posted a reply to In 2003, the number of girls attending Jefferson High in the Problem Solving forum
“Test the SMALLEST POSSIBLE CASE. Since both populations increase by 20% = 1/5, the original number of boys and the original number of girls must each be a multiple of 5. Since in 2003 there must be an equal number of boys and girls, the smallest possible case is as follows: 2003: boys = 5 and ...”
May 23, 2018
GMATGuruNY posted a reply to Much like the belief that the world is flat, challenged by in the Sentence Correction forum
“OA: Much like the belief that the world is flat, challenged by Galileo, there are currently widely-held hypotheses. Here, COMMA + challenged is incorrectly preceded by the clause in red. A COMMA + VERBed modifier must be preceded by a NOUN or NOUN PHRASE. Also, the referent for an introductory ...”
May 23, 2018
GMATGuruNY posted a reply to Low temperature in the Sentence Correction forum
“The conclusion in red is not necessarily true. and may serve to connect concurrent actions. Mary was sitting and reading. Here, the two actions in blue are performed at the same time.”
May 23, 2018
GMATGuruNY posted a reply to How many 4-digit integers have the form abcd, where b is eve in the Problem Solving forum
“Careful! The cases above are invalid because they violate the condition that b must be even.”
May 23, 2018
GMATGuruNY posted a reply to "A" and "B" run around a circular track in the Problem Solving forum
“Middle of the 5th round = 4.5 laps. (4 full laps + half of the 5th lap.) Since A''s rate = 70 seconds per lap, the time for A to complete 4.5 laps = (total number of laps)(number of seconds per lap) = (4.5)(70) = 315 seconds. We can PLUG IN THE ANSWERS, which represent the number of seconds for ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“For the 3 words to be switched on simultaneously, each must reach the END OF ITS RESPECTIVE ON-OFF CYCLE. On-off cycle for RON: (3 seconds on) + (47/6 seconds off) = 18/6 + 47/6 = 65/6 seconds. On-off cycle for AND: (3 seconds on) + (4/3 seconds off) = 18/6 + 8/6 = 26/6 seconds. On-off cycle ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“When an integer is raised to consecutive powers, the resulting units digits repeat in a CYCLE. 57867¹⁹²⁵⁷⁶: 7¹ --> units digit of 7. 7² --> units digit of 9. (Since the product of the preceding units digit and 7 = 7*7 = 49.) 7³ --> units digit of 3. (Since the product ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“Make a list of two-digit numbers that are 18 less than a perfect square: 36-18 = 18 49-18 = 31 64-18 = 46 81-18 = 63 100-18 = 82 Check whether each option above is equal to 18 less than the square of its digit sum: 18 = (1+8)² - 18 31 = (3+1)² - 18 46 = (4+6)² - 18 63 = (6+3)² - 18 ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“To MINIMIZE the number of rooms, we must MAXIMIZE the number of students per room. Let x = the number of students per room. Since each room must have x students -- and we want x to be as large as possible -- x must be equal to the GREATEST COMMON FACTOR of 315, 420, and 1155: 315 = 3*3*5*7 420 ...”
May 22, 2018
GMATGuruNY posted a reply to How many gallons of water must be mixed with 1 gallon in the Problem Solving forum
“Salt percentage in the original solution: 15%. Salt percentage in the added water: 0%. Salt percentage in the mixture: 10%. Let S = the original solution and W = the added water. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: Plot ...”
May 22, 2018
GMATGuruNY posted a reply to How many gallons of water must be mixed with 1 gallon in the Problem Solving forum
“Amount of salt = 15% of 1 gallon = 0.15 gallon. We can PLUG IN THE ANSWERS, which represent the amount of water that must be added to reduce the salt concentration to 10%. B: 2/3 gallon Salt concentration = (amount of salt)/(new total volume) = 0.15/(1 + 2/3) = 0.15/(5/3) = (0.15 * 3)/5 = ...”
May 22, 2018
GMATGuruNY posted a reply to Publishers of travel guides for families typically suffer in the Sentence Correction forum
“B: vacations budgets are low and their efforts to save are intense Here, their seems to refer to vacation budgets -- the nearest preceding plural noun -- implying that the efforts of VACATION BUDGETS are intense. This meaning is nonsensical. Eliminate B. C: more intense efforts Here, it is ...”
May 22, 2018
GMATGuruNY posted a reply to x+y=? in the Data Sufficiency forum
“Statement 1: Case 1: x=0, with the result that y = 3x = 3*0 = 0 In this case, x+y = 0+0 = 0. Case 2: x=1, with the result that y = 3x = 3*1 = 3 In this case, x+y = 1+3 = 4. Since x+y can be different values, INSUFFICIENT. Statement 2: Neither side of the equation can be negative, since the ...”
May 22, 2018
GMATGuruNY posted a reply to If ABCD is square and both AED and CDF are equilateral in the Problem Solving forum
“Because triangles ADE and CDF are equilateral, we get: https://s9.postimg.cc/xtqgckd9n/square_and_equilateral_triangles_1.png Because triangle AED is equilateral, DE = AD. Because ABCD is a square, AD = CD. .Thus, DE=CD, with the result that triangle CDE is isosceles: ...”
May 22, 2018
GMATGuruNY posted a reply to A jar contains 6 red marbles and 9 blue marbles. If Evelyn in the Problem Solving forum
“Case 1: 2 green marbles P(1st marble is green) = 6/15. (Of the 15 marbles, 6 are green.) P(2nd marble is green) = 5/14. (Of the 14 remaining marbles, 5 are green.) To combine these probabilities, we multiply: 6/15 * 5/14 = 1/7. Case 2: 2 red marbles P(1st marble is red) = 9/15. (Of the 15 ...”
May 21, 2018
GMATGuruNY posted a reply to Money invested at x%, compounded annually, triples in value in the Problem Solving forum
“The posted problem has a typo and should read as follows: Since x=8, the approximate number of years for the investment to triple = 112/x = 112/8 = 14. Since the initial investment = 2500, and the amount triples about every 14 years, we get: After the first 14 years --> 3*2500 = 7500. ...”
May 21, 2018
GMATGuruNY posted a reply to In what year was Edward born? in the Data Sufficiency forum
“Test EXTREMES. Case 1: Lisa''s birth month = January 1970 Since Edward was born 14 months earlier, Edward''s birth month = November 1968. Case 2: Lisa''s birth month = December 1970 Since Edward was born 14 months earlier, Edward''s birth month = October 1969. Since Edward''s birth year ...”
May 21, 2018
GMATGuruNY posted a reply to On Monday, Karen had S dollars in her savings account in the Problem Solving forum
“Alternate approach: Let S=30. The answer choices imply the following options for C: A) C=-10 B) C=10 C) C=20 D) C= 90 E) C = 100 From here, we can PLUG IN THE ANSWERS. When the correct answer is plugged in, the two accounts will hold the same amount after the transfer on Wednesday. ...”
May 21, 2018
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 B''s ...”
May 21, 2018
GMATGuruNY posted a reply to Last year's receipts from the sale of candy on Valentine's in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total sales. Since 385 represents 7% of the total sales, 10% of the correct answer must be a little more than 385. Only D is viable: 10% of 5500 = 550. The correct answer is D.”
May 21, 2018
GMATGuruNY posted a reply to OG 10th Edition Q 74 in the Critical Reasoning forum
“The correct answer must support the conclusion that a well-balanced breakfast is a better vitamin source than is a fortified breakfast cereal.. A: In many foods, the natural combination of vitamins with other nutrients makes those vitamins more usable by the body than are vitamins added in ...”
May 21, 2018
GMATGuruNY posted a reply to A study done on children under the age of twelve showed in the Sentence Correction forum
“The intention here is to convey the following: The study showed THAT X IS TRUE but THAT Y IS TRUE. For the intended meaning to be conveyed clearly, the second that is required. A and B: The study...showed that....but for C: The study showed that...but when These options do not include the ...”
May 21, 2018
GMATGuruNY posted a reply to If 123,456=123a+87 and 234,567=123b+6, how many multiples o in the Problem Solving forum
“For any EVENLY SPACED SET: Count = (biggest - smallest)/increment + 1. The INCREMENT is the difference between successive terms. Smallest multiple of 123 between 123a + 87 and 123b + 6: 123a +123. Biggest multiple of 123 between 123a + 87 and 123b + 6: 123b. Since 123 is the increment ...”
May 21, 2018
GMATGuruNY posted a reply to Jayden draws a regular n-gon. What is the value of n? in the Data Sufficiency forum
“Sum of the interior angles of a quadrilateral = 360, with the result that each angle of a square = 360/4 = 90. For each additional side, the sum of the interior angles increases by 180: Sum of the interior angles of a pentagon = 360+180 = 540, with the result that each angle of a regular pentagon ...”
May 21, 2018
GMATGuruNY posted a reply to statements must be true for all integers a, b and c? in the Problem Solving forum
“a@b = a + b - ab. In other words, a@b = SUM - PRODUCT. Statement I is included in four of the five answer choices. Thus, it is almost certain that statement I must be true. Otherwise, a test-taker will be able to eliminate four answer choices simply by evaluating statement I. To save time, ...”
May 20, 2018
GMATGuruNY posted a reply to A boyis buying two kinds of marbles. One kind costs 25 cents in the Problem Solving forum
“I believe that the following represents the intent of the problem: Cost of 5 pounds of 25-cent marbles = 5*25 = 125 cents. We can PLUG IN THE ANSWERS, which represent the number pounds of 32-cent marbles. When the correct answer is plugged in the average cost per marble ≈ 29. B: 6 ...”
May 19, 2018
GMATGuruNY posted a reply to Two liquids are mixed in the ratio 3:2 and the vendor gains in the Problem Solving forum
“Since the selling price of $11 per liter represents a profit of 10%, the cost per liter = $10. The cost of the first liquid is $2 more than the cost of the second liquid. For the average cost per liter to be $10, the cost of the first liquid must be MORE THAN $10, while the cost of the second ...”
May 19, 2018
GMATGuruNY posted a reply to A farmer who grows strawberries defines . . . in the Data Sufficiency forum
“Statement 1: Since the size of the crop is unknown, we cannot determine how many workers must be hired for the crop to be picked in 15 days. INSUFFICIENT. Statement 2: For 13,500 liters to be picked in 15 days, the amount that must be picked each day = 13,500/15 = 900 liters. Since the rate ...”
May 19, 2018
GMATGuruNY posted a reply to Employment costs rose - GMATPrep in the Sentence Correction forum
“In B, it (singular) does not agree with costs (plural). Eliminate B. C: Employment costs rose...less than they were Here, an ACTION (rose) is illogically compared to a STATE-OF-BEING (were). Eliminate C. lower is an ADJECTIVE. It must serve to modify a NOUN. D and E: Employment costs ...”
May 19, 2018
GMATGuruNY posted a reply to OG 16 Question 27 in the Sentence Correction forum
“One reason to eliminate B: Generally, a COMMA + VERBing modifier must serve to express an action that is concurrent with the nearest preceding action. B implies the following: The Etruscan alphabet in turn had been adapted, adapting itself earlier. Here, the COMMA + VERBing action in red is ...”
May 18, 2018
GMATGuruNY posted a reply to Each of 60 mineral water bottles in a certain shipment is in the Problem Solving forum
“The addition of the word in red clarifies the intent of the problem: Curren total volume = (number of bottles)(average volume per bottle) = 60*800 = 48,000 ml. We can PLUG IN THE ANSWERS, which represent the number of 1000-ml bottles that must be removed to reduce the average volume per ...”
May 18, 2018
GMATGuruNY posted a reply to On May 1 of last year, Jasmin invested x dollars . . . . in the Data Sufficiency forum
“Statement 1: Since we know the interest rate (6% per year, compounded monthly) and the amount of interest earned after one month ($200), we can calculate the amount Jasmin must have invested. SUFFICIENT. Statement 2: Since we know the interest rate (6% per year, compounded monthly) and the ...”
May 18, 2018
GMATGuruNY posted a reply to The Number of students learning Three subjects are as in the Problem Solving forum
“https://s9.postimg.cc/nom8j2aej/math_english_science.png The values in blue represent the number of students studying exactly 1 subject. Sum of the values in blue: 125 - 2(a+b+c). To MINIMIZE the value of this expression, we must MAXIMIZE the value of a+b+c. Since the expression must be ...”
May 18, 2018
GMATGuruNY posted a reply to A shop sells two variants of chocolates - one that costs 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, Since the price of each chocolate is either $3 or $5, and the total amount sold = $108, we get: 3x + 5y = 108. Since 108 is an integer whose digits sum to a multiple of 3, 108 is a ...”
May 18, 2018
GMATGuruNY posted a reply to The number of coins that Lana and Brad had were in the in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represent the difference between Lana and Brad after the 8-coin gift. When the correct answer is plugged in, the ratio for Lana and Brad before the 8-coin gift = 5/2. D: 14 After the 8-coin exchange: The parts of the resulting ratio for ...”
May 17, 2018
GMATGuruNY posted a reply to Right now, a barrel of water is exactly 40% full of water. in the Data Sufficiency forum
“Since every value in the problem is either a fraction or a percentage -- and no actual volumes are given -- the capacity of the barrel can be any value. Thus, the two statements combines are INSUFFICIENT. The correct answer is E. The phrase in red is ambiguous and would not appear in an ...”
May 17, 2018
GMATGuruNY posted a reply to Is n an integer? in the Data Sufficiency forum
“Both statements are satisfied by the following cases: Case 1: n = 1, with the result that 2n = 2 and 1/n = 1 In this case, n is an integer, so the answer to the question stem is YES. Case 2: n = 1/2, with the result that 2n = 1 and 1/n = 2 In this case, n is NOT an integer, so the answer to the ...”
May 17, 2018
GMATGuruNY posted a reply to How many 4-digit numbers have only even digits? in the Problem Solving forum
“Number of options for the thousands digit = 4. (2, 4, 6, or 8) Number of options for the hundreds digit = 5. (0, 2, 4, 6, or 8) Number of options for the tens digit = 5. (0, 2, 4, 6, or 8) Number of options for the units digit = 5. (0, 2, 4, 6, or 8) To combine these options, we multiply: ...”
May 17, 2018
GMATGuruNY posted a reply to If xy < 4, is x < 2? in the Data Sufficiency forum
“Statement 1: Case 1: y=2 and x=1, with the result that xy < 4 In this case, x<2, so the answer to the question stem is YES. Case 2: y=3/2 and x=2, with the result that xy < 4 In this case, x=2, so the answer to the question stem is NO. Since the answer is YES in Case 1 but NO in Case ...”
May 16, 2018
GMATGuruNY posted a reply to What is the product of all the possible values of x if in the Problem Solving forum
“x²(x+2) + 7x(x+2) + 6(x+2) = 0. Factor out x+2: (x+2)(x² + 7x + 6) = 0 Factor the quadratic in red: (x+2)(x+6)(x+1) = 0 Option for x: x=-2, x=-6, x==-1. Thus, the product of all the solutions = (-2)(-6)(-1) = -12. The correct answer is B.”
May 16, 2018
GMATGuruNY posted a reply to There are 8 books in a shelf that consists of 2 paperback in the Problem Solving forum
“Combinations with at least 1 paperback = (all possible combinations) - (combinations with no paperbacks). All possible combinations: From the 8 books, the number of ways to choose 4 = 8C4 = (8*7*6*5)/(4*3*2*1) = 70. Combinations with no paperbacks: From the 6 hardback books, the number ...”
May 15, 2018
GMATGuruNY posted a reply to Although the bite of brown recluse spiders are rarely fatal in the Sentence Correction forum
“A and B: Although the bite...are rarely fatal Here, are (plural) does not agree with the bite (singular). Eliminate A and B. C: the bite...posing the greatest danger to the infant and elderly, who are particularly vulnerable to their poison Here, their (plural) does not agree with the bite ...”
May 15, 2018
GMATGuruNY posted a reply to In a certain theater, the first row has 12 seats, and each r in the Problem Solving forum
“Since each row has 1 more seat than the preceding row, the row tallies form a set of consecutive integers: 12, 13, 14...48, 49. 50. For any set of consecutive integers: Count = biggest - smallest + 1 Average = (biggest + smallest)/2 Sum = (count)(average). In the problem at hand: Smallest ...”
May 15, 2018
GMATGuruNY posted a reply to How many solutions are possible for the inequality | x - 1 | in the Problem Solving forum
“|a-b| = the DISTANCE between a and b. Thus: |x-1| = the distance between x and 1. |x-6| = the distance between x and 6. Question stem rephrased: For how many values of x is the sum of the two distances less than 2? The distance between 1 and 6 is 5. Thus, if x is BETWEEN the ...”
May 15, 2018
GMATGuruNY posted a reply to Trains A and B travel at the same constant rate in opposite in the Data Sufficiency forum
“Statement 1: Whereas A travels for 2 hours, B begins its journey 1 hour later and travels for 1 hour. A ----------2 hours----------> meeting spot <-----1 hour----- B Since A travels at r miles per hour for 2 hours to meet B, and B travels at r miles per hour for 1 hour to meet A, it takes a ...”
May 14, 2018
GMATGuruNY posted a reply to If x is a positive integer, what is the least common in the Data Sufficiency forum
“Statement 1: x must be a factor of 30 such that the smallest value divisible by both x and 6 is 30. Options for x: x=5, 10, 15, 30. In every case, the LCM for x , 6, and 9 is 90. SUFFICIENT. Statement 2: x must be a factor of 45 such that the smallest value divisible by both x and 9 is 45. ...”
May 14, 2018
GMATGuruNY posted a reply to If y is positive, what is the value of x? in the Data Sufficiency forum
“Since y is positive, |y| = y. Statement 1: x - y = -x - |y| x - y = -x - y x = -x 2x = 0 x = 0. SUFFICIENT. Statement 2: x = y-3 If y=1, then x = 1-3 = -2. If y=2, then x = 2-3 = -1. Since x can be different values, INSUFFICIENT. The correct answer is A.”
May 14, 2018
GMATGuruNY posted a reply to If a = 4b, what percent of 2a is 2b? in the Problem Solving forum
“= Let b=1, implying that a = 4b = 4*1 = 4. What percent of 2a is 2b? 2b/2a = b/a = 1/4 = 25%. The correct answer is C.”
May 14, 2018
GMATGuruNY posted a reply to John bought a shirt, a pair of pants, and a pair of shoes in the Problem Solving forum
“(pant cost)/(total cost) = 20/(10+20+30) = 20/60 = 1/3 = 33⅓%. The correct answer is D.”
May 14, 2018
GMATGuruNY posted a reply to Is |a| + |b| > |a + b| ? in the Data Sufficiency forum
“Is |a| + |b| > |a + b|? Because an absolute value cannot be negative, both sides of the inequality above are NONNEGATIVE, allowing us to SQUARE the inequality (|a| + |b|)² > (|a + b|)² a² + 2|a||b| + b² > a² + 2ab + b² 2|a||b| > 2ab |a||b| > ab. The resulting inequality ...”
May 14, 2018
GMATGuruNY posted a reply to Verbal Review 18 : Kudzu, an Asian vine in the Sentence Correction forum
“Generally, the usage of a passive verb implies one or both of the following: 1. The agent of the passive action is unknown. 2. The agent of the passive action is unimportant to the meaning of the sentence. The SC above is concerned primarily with the rampant GROWTH of Kudzu. To understand this ...”
May 13, 2018
GMATGuruNY posted a reply to Verbal Review 18 : Kudzu, an Asian vine in the Sentence Correction forum
“New genetic evidence provides compelling support for classifying Africa’s forest elephants and its savanna elephants as separate species. Here, for classifying is an adjective serving to describe support. Question: What KIND of support? Answer: support FOR CLASSIFYING.”
May 13, 2018
GMATGuruNY posted a reply to Sentence Correction Question in the Sentence Correction forum
“The SC above appears in GMATPrep. The OA is not C but D.”
May 12, 2018
GMATGuruNY posted a reply to A, B, C, D and E are 5 consecutive points on a straight in the Problem Solving forum
“AB = 5: https://s7.postimg.cc/qie6ijplj/ABCDE_1.png AC = 11: https://s7.postimg.cc/de8m615bb/ABCDE_2.png BC = 2CD: https://s7.postimg.cc/pu5bzcj3b/ABCDE_3.png DE = 4: https://s7.postimg.cc/fk2x04gd3/ABCDE_final.png Thus, AE = 5 + 6 + 3 + 4 = 18. The correct answer is D.”
May 12, 2018
GMATGuruNY posted a reply to The line represented by the equation y=4-2x is the in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the coordinates of point P. The slopes of perpendicular lines are NEGATIVE RECIPROCALS. Since y = -2x + 4 has a slope of -2, perpendicular line segment RP must have a slope of 1/2. Implication: When the correct answer is combined with the coordinates ...”
May 12, 2018
GMATGuruNY posted a reply to An escalator moves downward from street level to a subway in the Problem Solving forum
“DOWNWARD: When the escalator is turned OFF, the number of steps taken by Wesley to travel downward = 70. When the escalator is turned ON, the number of steps taken by Wesley to travel downward = 36, implying that the number of downward steps attributed to the escalator = 70-36 = 34. Implication: ...”
May 11, 2018
GMATGuruNY posted a reply to Twice the birds as last year will migrate to the in the Sentence Correction forum
“A: twice the birds as last year Here, BIRDS are illogically compared to LAST YEAR. Eliminate A. B: double the number...as last year Here, THE NUMBER is illogically compared to LAST YEAR. Eliminate B. C and E: that of last year''s Here that OF and last year''s both serve to convey ...”
May 11, 2018
GMATGuruNY posted a reply to Sentence Correction Question in the Sentence Correction forum
“A, B and C: three times AS many...charge under $8000 a year THAN In these options, than is unidiomatic. Correct: as many X AS Y. Eliminate A, B and C. Only PARALLEL FORMS may be compared. E: three times as many...CHARGE under $8000...as those CHARGING over $16,000. Here, charge is a VERB, ...”
May 11, 2018
GMATGuruNY posted a reply to If the terms of a sequence {An} are defined by An=n/100, whe 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. Integers between 101 and 200, inclusive: Here, the integers are CONSECUTIVE, so the increment = ...”
May 11, 2018
GMATGuruNY posted a reply to The sum S of the arithmetic sequence a, a+d, a+2d,..., a+(n- 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. Integers between 1 and 100, inclusive: Here, the integers are CONSECUTIVE, so the increment = 1. ...”
May 11, 2018
GMATGuruNY posted a reply to (2^5+2^6+2^7+2^8)^2=? in the Problem Solving forum
“(2⁵ + 2⁶ + 2⁷ + 2⁸)² = E.”
May 10, 2018
GMATGuruNY posted a reply to The probability of shooting a target increases after a in the Problem Solving forum
“Test an EASY CASE. Let: S = the original probability of shooting the target NS = the original probability of NOT shooting the target New S = the new probability of shooting the target New NS = the new probability of NOT shooting the target Case 1: Let NEW NS = 0.1, implying that the NEW S = ...”
May 10, 2018
GMATGuruNY posted a reply to abc0 is a positive, four-digit integer, where a, b and c are in the Data Sufficiency forum
“An integer is divisible by 4 only if its last two digits form a multiple of 4. For example: 93724 is divisible by 4 because its last two digits -- 2 and 4 -- form 24, which is a multiple of 4. Question stem, rephrased: Is the integer c0 a multiple of 4? Statement 1: No information about c. ...”
May 10, 2018