GMATGuruNY posted a reply to A number when divided by 4 and 5 leaves remainders 1 and 4 in the Problem Solving forum
“Please fix the prompt, which has been transcribed incorrectly. It should include the word in red:”
Yesterday
GMATGuruNY posted a reply to A woman has seven cookies - four chocolate chip and three in the Problem Solving forum
“Alternate approach: Case 1: Deborah and Kim each receive an oatmeal cookie In this case, 4 chocolate chip cookies and 1 oatmeal cookie remain. The remaining oatmeal cookie has 5 options: Nicole, Ronit, Mark, Terrance, or no one. Total ways = 5. Case 2: Deborah and Kim each receive a ...”
Yesterday
GMATGuruNY posted a reply to The Lewiston Road Race is how many kilometers long? in the Data Sufficiency forum
“Statement 1: Rate and time have a RECIPROCAL relationship. A rate ratio of (40kph) : (50kph) = 4:5 implies a time ratio of 5:4 = 10:8. The time ratio in blue implies that -- for the time at 40kph to be 2 hours more than the time at 50kph -- the time at 40kph must be 10 hours, while the time at ...”
November 17, 2018
GMATGuruNY posted a reply to Tim and Glenn are running laps around a circular track. in the Data Sufficiency forum
“Statement 1: The TIME RATIO for Tim and Glenn = 48:60 = 4:5. Since time and rate have a RECIPROCAL relationship, the RATE RATIO for Tim and Glenn = 5:4. Implication: For every 5 laps that Tim runs, Glenn runs only 4 laps. Thus, after running 5 laps, Tim will have run 1 more lap than Glenn. ...”
November 16, 2018
GMATGuruNY posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom in the Problem Solving forum
“Let the one-bedroom rent = $2 per month, implying that the two-bedroom rent = 2 + (50% of 2) = 2 + 1 = $3 per month. Since the rent for a one-bedroom apartment = $2 per month, the total amount to rent a one-bedroom apartment for 12 months = 2*12 = $24. For $24, the number of months yielded for a ...”
November 16, 2018
GMATGuruNY posted a reply to A certain store will order 25 crates of apples. The apples in the Problem Solving forum
“Let W = Winesap crates, M = McIntosh crates, and R = Roma crates. Since a total of 25 crates are ordered, we get: W + M + R = 25. To MINIMIZE the value of W, we must MAXIMIZE the values of M and R. Since the store is to order more crates of Winesap than crates of McIntosh and more crates of ...”
November 15, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“The prompt states: Every day, the two machines operate constantly from 08:00 to 18:00. As shown in my post above, Statement 2 yields the following rate ratio: (W alone) : (W and D together) = 1:5. The rate ratio indicates that -- of every 5 kg produced when W and D work together from 8:00 to ...”
November 15, 2018
GMATGuruNY posted a reply to Organized in 1966 by the Fish and Wildlife in the Sentence Correction forum
“Generally, for + VERBing is an ADJECTIVE serving to modify a NOUN. A: The Breeding Bird Survey uses annual roadside counts along established routes for monitoring. Here, for monitoring seems to be an ADJECTIVE modifying routes, implying that the ROUTES were designed FOR MONITORING. Not the ...”
November 15, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“Statement 1: Let N = 50 kg. Since W and D produce the entire 50 kg over the 10 hours between 8:00 and 18:00, the combined rate for W and D = 50/10 = 5 kg per hour. Since W takes 25 hours to produce N/2 = 25 kg, W''s rate alone = w/t = 25/25 = 1 kg per hour. Of every 5 kg produced each hour ...”
November 14, 2018
GMATGuruNY posted a reply to If x and y are unknown positive integers, is the mean of the in the Data Sufficiency forum
“Known values, in ascending order: 1, 5, 6, 7 Statement 1: x+y = 7 Mean = sum/quantity = (1+5+6+7+x+y)/6 = (1+5+6+7+7)/6 = 26/6 = 13/3 = 4.33. Text EXTREMES. Case 1: x and y are far from each other If x=1 and y=6, we get: 1, 1. 5, 6, 6, 7 Median = (5+6)/2 = 11/2 = 5.5 Case 2: x and y ...”
November 14, 2018
GMATGuruNY posted a reply to How many positive two-digit numbers yield a remainder of 1 in the Problem Solving forum
“Let x = the two-digit number. Since dividing by 4 leaves a remainder of 1, x is equal to one more than a multiple of 4: x = 4k + 1 Since dividing by 14 leaves a remainder of 1, x is equal to one more than a multiple of 14: x = 14m + 1 Since the two expressions in blue must be equal, we ...”
November 14, 2018
GMATGuruNY posted a reply to On a wedding catering service, An experienced chef can in the Problem Solving forum
“Let service = 24 units. Rate for each experienced chef = w/t = 24/8 = 3 units per hour. Rate for each novice chef = w/t = 24/12 = 2 units per hour. Combined rate for 1 experienced chef and 1 novice chef working together = 3+2 = 5 units per hour. To produce 24 units in 1.6 hours, rate = w/t = ...”
November 13, 2018
GMATGuruNY posted a reply to Jake and Ryan worked together on a job for which they were in the Problem Solving forum
“Let the hourly wage = $1 per hour. Let Ryan''s time = 10 hours, implying that Jake''s time = 10 + (20% of 10) = 10 + 2 = 12 hours. Thus: Total number of work hours = 10+12 = 22 hours. Total pay = (hourly wage)(total number of work hours) = 1*22 = $22. Since the total pay = 10+12 = $22, and ...”
November 13, 2018
GMATGuruNY posted a reply to A store purchased 20 coats that each cost an equal amount in the Data Sufficiency forum
“Statement 1: If the selling price per coat had been twice as much , the store’s gross profit on the 20 coats would have been $2,400 When the selling price per coat is doubled, the resulting profit per coat = (total profit)/(number of coats) = 2400/20 = 120. Case 1: Double the selling price = ...”
November 13, 2018
GMATGuruNY posted a reply to If 60! is written out as an integer, with how many in the Problem Solving forum
“60! = 60*59*58*....*3*2*1. Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of 60! will yield a 0 at the end of the integer representation of 60!. The prime-factorization of 60! is composed of FAR MORE 2''S than 5''s. Thus, the number of 0''s depends on the ...”
November 13, 2018
GMATGuruNY posted a reply to In the figure AB and CD are two diameters of circle. in the Problem Solving forum
“An INSCRIBED ANGLE is formed by two chords. A CENTRAL ANGLE is formed by two radii. When an inscribed angle and a central angle intercept the same two points on a circle, the inscribed angle is 1/2 the central angle. https://i.postimg.cc/qgbxWKdW/Angle-CEB-1.png Here, inscribed angle CFB and ...”
November 12, 2018
GMATGuruNY posted a reply to If x and y are positive integers such that x = 8y + 12, what in the Data Sufficiency forum
“Statement 1: x=12u, where u is an integer and x=8y+12. In other words, x is a multiple of 12. For x to be a multiple of 12, 8y must be a multiple of 12. If y=3, then x = 8*3 + 12 = 36. The GCD of 3 and 36 is 3. If y=6, then x = 8*6 + 12 = 60. The GCD of 6 and 60 is 6. Since the ...”
November 11, 2018
GMATGuruNY posted a reply to Eight women and two men are available to serve on a in the Problem Solving forum
“P(at least 1 man) = 1 - P(no men). P(no men): P(1st person selected is a woman) = 8/10. (Of the 10 people, 8 are women.) P(2nd person selected is a woman) = 7/9. (Of the 9 remaining people, 7 are women.) P(3rd person selected is a woman) = 6/8. (Of the 8 remaining people, 6 are women.) To ...”
November 11, 2018
GMATGuruNY posted a reply to A gardener is going to plant 2 red rosebushes and 2 white in the Problem Solving forum
“Moving LEFT TO RIGHT along the row: P(1st rosebush is white) = 2/4. (Of the 4 rosebushes, 2 are white.) P(2nd rosebush is red) = 2/3. (Of the 3 remaining rosebushes, 2 are red.) P(3rd rosebush is red) = 1/2. (Of the 2 remaining rosebushes, 1 is red.) P(4th rosebush is white) = 1/1. (The one ...”
November 10, 2018
GMATGuruNY posted a reply to Every day at noon, a bus leaves for Townville and travels at in the Problem Solving forum
“Time and rate have a RECIPROCAL RELATIONSHIP: 2 times as fast implies 1/2 the time. 3 times as fast implies 1/3 the time. Let t = the normal time. Since the bus travels today at 7/6 its normal rate, the time today is equal to 6/7 of the normal time: (6/7)t. Since the bus leaves 1/2 hour late ...”
November 9, 2018
GMATGuruNY posted a reply to There are 27 different three-digit integers that can be in the Problem Solving forum
“Given any set that is symmetrical about the median: Sum = (quantity)(median) The set of 3-digit integers that can be formed from the digits 1,2 and 3 is symmetrical about the median (222): ...212, 213, 221, 222, 223, 231, 232... Thus: Sum of the 27 integers = (quantity)(median) = 27*222 = ...”
November 7, 2018
GMATGuruNY posted a reply to Is x^2>xy? in the Data Sufficiency forum
“For the purposes of a Y/N DS problem, the rephrase is the equivalent of the original question stem. Original question stem: Is x² > xy? The answer will be YES if y/x is less than 1.. The answer will be NO if y/x is NOT less than 1. Thus, the original question stem can be rephrased as ...”
November 5, 2018
GMATGuruNY posted a reply to Is x^2>xy? in the Data Sufficiency forum
“x² > xy is true only if x is NONZERO, in which case we can safely divide by x², since the square of a nonzero value must be positive: x²/x² > (xy)/x² 1 > y/x Question stem, rephrased: Is y/x < 1? Statement 1: x > y If x=2 and y=1, then y/x =1/2. so the answer to the ...”
November 5, 2018
GMATGuruNY posted a reply to | 1 - | 2 - | 3 - | 4 – π | | | | in the Problem Solving forum
“Let π=3 in the original expression and simplify the blue portion below: | 1 - | 2 - | 3 - | 4 – 3 | | | | Simplify the red portion below; | 1 - | 2 - | 3 - 1 | | | Simplify the green portion below: | 1 - | 2 - 2 | | = | 1 - 0 | = 1 The correct answer choice must yield a value of ...”
November 5, 2018
GMATGuruNY posted a reply to Working alone, three persons P, Q, and R can do a certain in the Problem Solving forum
“Let the job = the LCM of the 3 times = 60 widgets. Maximum time: The maximum time is yielded when the slowest person -- R -- works alone. Since R takes 15 hours to complete the 60-widget job, the maximum time = 15 hours. Minimum time: The minimum time is yielded when all 3 people work ...”
November 4, 2018
GMATGuruNY posted a reply to Triplets Adam, Bruce, and Charlie enter a triathlon. If ther in the Problem Solving forum
“One approach: P(good outcome) = 1 - P(bad outcome). Bad outcome #1: Exactly 1 triplet wins. P(triplet wins 1st place) = 3/9. (Of the 9 competitors, 3 are triplets) P(non-triplet wins 2nd place) = 6/8. (Of the 8 remaining competitors, 6 are non-triplets) P(non-triplet wins 3rd place) = 5/7. ...”
November 4, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“Nicely done! Because the comparison in D allows for more than one logical interpretation, eliminate D. In fact, the ambiguity cited above is the most compelling reason to eliminate D.”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“X led to Y implies that X did not directly cause Y but that X was a factor that helped to yield Y. SC755 in the OG17: An inability to adapt led to their extinction. Here, an inability to adapt did not directly cause the extinction but was a factor that helped to yield the extinction. A cause ...”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“Generally, COMMA + as-clause implies that the clause after as LEADS to the preceding clause, with the result that the two clauses happen concurrently. An OA in GMATPrep: The steel industry has changed radically over the last two decades, as large, integrated companies such as Bethlehem Steel have ...”
November 2, 2018
GMATGuruNY posted a reply to Barry walks from one end to the other of a 30-meter long in the Problem Solving forum
“Let B = Barry''s rate and W = the walkway''s rate. The distance can be ANY VALUE. Let the distance = 240 meters. WITH the walkway, the time = 30 seconds: Here, Barry and the walkway WORK TOGETHER, so we ADD their rates: B+W = d/t = 240/30 = 8 meters per second. AGAINST the walkway, the ...”
November 2, 2018
GMATGuruNY posted a reply to At a family summer party, each of the x members of the in the Problem Solving forum
“Let the x family members = the product of the two denominators = 3*7 = 21. Number who chose to have a hamburger = (1/3)(21) = 7. Since 1/7 of the hamburger-eaters also had a hot dog, the number who had both = (1/7)(7) = 1. Thus, the number who did NOT have both = (total members) - (number who had ...”
November 1, 2018
GMATGuruNY posted a reply to How many positive five-digit integers contain the digit in the Problem Solving forum
“I believe that the prompt above is outdated; regardless, it does not list a correct answer. The prompt below appears in Manhattan''s 5 lb. Book of GRE Practice Problems: Case 1: 57XXX Number of options for the hundreds digit = 10. (Any digit 0-9.) Number of options for the tens digit = 10. ...”
November 1, 2018
GMATGuruNY posted a reply to Two teachers, Ms. Ames and Mr. Betancourt, each had N in the Data Sufficiency forum
“Since the N cookies can be divided evenly among 24 or 18 students, N must be divisible by both 24 and 18. One way to determine the LCM of two integers is to take multiples of the LARGER integer until we get a multiple of the SMALLER integer. Multiples of 24: 24, 48, 72... We can stop here: the ...”
November 1, 2018
GMATGuruNY posted a reply to Did one of the 3 members of a certain team sell at least 2 in the Data Sufficiency forum
“Statement 1: If NONE of the members sells at least 2 tickets, then the 3 members sell a maximum of 1 ticket each, yielding the following total: 1+1+1 = 3. Too small, since the total number of tickets sold = 6. Implication: For a total of 6 tickets to be sold, one of the 3 members must sell at ...”
October 31, 2018
GMATGuruNY posted a reply to A football team averaged 35 points per game over the first in the Problem Solving forum
“This is a weighted average/mixture problem. Average score for the first N games = 35. Score for the final game = 28. Average score for the MIXTURE of all the games = 34. Step-by-step instruction for the alligation approach: Step 1: Plot the 3 averages on a number line, with the average ...”
October 31, 2018
GMATGuruNY posted a reply to 3, 6, 9, 12, … are multiples of 3. How many multiples of 3 in the Problem Solving forum
“The difference between the endpoints of the range = 200-10 = 190. Since neither endpoint is a multiple of 3, we can count the multiples of 3 simply by dividing 3 into 190: 190/3 ≈ 63. The correct answer is D.”
October 31, 2018
GMATGuruNY posted a reply to A group of 20 friends formed an investment club, with each in the Problem Solving forum
“Let d=100. After the value of the stock increases by 40% to $140, the share received by each of the 20 friends = 140/20 = 7. The correct answer must yield a value of 7 when d=100. Only E works: (7d)/100 = (7*100)/100 = 7. The correct answer is E.”
October 30, 2018
GMATGuruNY posted a reply to The average weight of a class is x pounds. When a new in the Problem Solving forum
“We can PLUG IN THE ANSWERS and use alligation. To learn about alligation, check my posts here: https://www.beatthegmat.com/statistics-average-question-t288903.html https://www.beatthegmat.com/alligation-method-t293459.html https://www.beatthegmat.com/mean-t266852.html Let O = the original ...”
October 30, 2018
GMATGuruNY posted a reply to Machines X and Y can work at their respective constant rates in the Data Sufficiency forum
“Statement 1: Time and rate have a RECIPROCAL relationship. Since X and Y together take 2/3 as long as Y alone, X and Y together work 3/2 as fast as Y alone. Thus, if Y''s rate alone = 2 units per hour, then X and Y''s combined rate = (3/2)(2) = 3 units per hour, implying that X''s rate alone = ...”
October 30, 2018
GMATGuruNY posted a reply to Set S contains nine distinct points in the coordinate plane. in the Problem Solving forum
“To form a triangle, we must select 3 points such that at most 2 are collinear. Case 1: Select 3 points not on the x-axis From the 4 points not on the x-axis, the number of ways to choose 3 = 4C3 = (4*3*2)/(3*2*1) = 4. Case 2: Select 1 point on the x-axis and two points not on the x-axis From ...”
October 29, 2018
GMATGuruNY posted a reply to Employees at a company will vote for an executive team of in the Problem Solving forum
“Number of options for president = 8. (Any of the 8 candidates.) Number of options for treasurer = 7. (Any of the 7 remaining candidates.) From the 6 remaining people, the number of ways to choose 3 to serve as warrant officers = 6C3 = (6*5*4)/(3*2*1) = 20. To combine these options, we multiply: ...”
October 29, 2018
GMATGuruNY posted a reply to A set of pencils can be evenly shared between 2, 3, 4, 5 and in the Problem Solving forum
“For the set of pencils to be shared evenly, the total number of pencils must be divisible by the total number of children. Thus, the correct answer must be divisible by 2, 3, 4, 5 and 6. Of the five answer choices, only E is divisible by 2, 3, 4, 5 and 6. The correct answer is E.”
October 29, 2018
GMATGuruNY posted a reply to (x^2-3x+2)(y^2-5y+6)=? in the Data Sufficiency forum
“Statement 1: Substituting x=1 into (x² - 3x + 2)(y² - 5x + 6), we get: (1 - 3*1 + 2)(y² - 5x + 6) = (0)(y² - 5x + 6) = 0. SUFFICIENT. Statement 2: Substituting y=1 into (x² - 3x + 2)(y² - 5x + 6), we get: (x² - 3x + 2)(1² - 5*1 + 6) = (x² - 3x + 2)(2). Since the value of x is ...”
October 29, 2018
GMATGuruNY posted a reply to How many integers are there between, but not including, in the Data Sufficiency forum
“Statement 1: Case 1: r=0 and s=10 Integers between r and s: 1, 2, 3, 4, 5, 6, 7, 8, 9 --> 9 integers Case 2: r=1 and s=11 Integers between r and s: 2, 3, 4, 5, 6, 7, 8, 9, 10 --> 9 integers Case 3: r=2 and s=12 Integers between r and s: 3, 4, 5, 6, 7, 8, 9, 10, 11 --> 9 ...”
October 28, 2018
GMATGuruNY posted a reply to Both Betty and Wilma earn annual salaries of more than $5000 in the Data Sufficiency forum
“Statement 1: Betty''s annual salary is closer to $50000 than Wilma''s is. On a number line: -----50,000---B---W Thus, W > B. SUFFICIENT. Statement 2: Betty''s annual salary is closer to $35000 than it is to Wilma''s annual salary. Case 1: -----35,000-----50,000---B---W Case 2: ...”
October 28, 2018
GMATGuruNY posted a reply to In a right triangle, the longer leg is two more than three in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the length of the shorter leg. When the correct answer is plugged in, the area = 400. B: 20 Longer leg = two more than three times the shorter leg = 2 + 3*20 = 62. Area = (1/2)(20)(62) = 620. Since the area is too great, a smaller answer choice is ...”
October 27, 2018
GMATGuruNY posted a reply to A framed picture is shown above. The frame, shown shaded, is in the Data Sufficiency forum
“Statement 1: Test one case that also satisfies Statement 2. Case 1: The frame is 8 inches tall, with the result that the total area of the frame and picture combined = 6*8 = 48 Area of the picture = (total area) - (shaded region) = 48-24 = 24. Implication: The width of the frame is 1 inch, ...”
October 27, 2018
GMATGuruNY posted a reply to What is the largest prime factor of the expression 3^8 − 2 in the Problem Solving forum
“A general rule: Given x^(even power) - y^(even power), where x and y are distinct positive integers, we can always simplify by applying the difference of two squares. Each time we apply the difference of two squares to the expression in blue, the exponents are reduced by 1/2. For example: x⁸ - ...”
October 26, 2018
GMATGuruNY posted a reply to Jazz and blues recordings accounted for 6 percent of the in the Data Sufficiency forum
“Let J = jazz and blues revenue in 1998. Statement 1: Case 1: Total revenue in 1998 = 100 In this case, J = 5% of 100 = 5. Case 2: Total revenue in 1998 = 1000 In this case, J = 5% of 1000 = 50. Since J can be different values, INSUFFICIENT. Statement 2: In other words: (jazz and blues ...”
October 26, 2018
GMATGuruNY posted a reply to x and y are non-negative integers. If xy+2x+3y=0, then y=? in the Problem Solving forum
“NONNEGATIVE implies that we should test ZERO. Let x=0. Substituting x=0 into xy + 2x + 3y = 0, we get: 0*y + 2*0 + 3y = 0 3y = 0 y = 0 The correct answer is A.”
October 26, 2018
GMATGuruNY posted a reply to Set S contains consecutive natural numbers from 1 to 100, in in the Problem Solving forum
“For any evenly spaced set: sum = (count)(median) Sum of the first n even numbers = n * median of the first n even numbers Sum of the last n odd numbers = n * median of the last n odd numbers Since the ratio of the two sums = 16/85, we get: (n * median of the first n even numbers) / (n * ...”
October 26, 2018
GMATGuruNY posted a reply to Quentin's income is 60% less than Rex's income, and Sam's in the Problem Solving forum
“Let Rex''s income = 100. Since Quentin''s income is 60% less than Rex''s, Quentin''s income = 100 - (60% of 100) = 100-60 = 40. Since Sam''s income is 25% less than Quentin''s, Sam''s income = 40 - (25% of 40) = 40-10 = 30. After Rex gives 60% of his income to Sam, Sam''s new income = 30 + (60% ...”
October 25, 2018
GMATGuruNY posted a reply to If |x-6|=2x, then x=? in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of x. Since an absolute value cannot be equal to a negative value, the correct answer cannot be A or B. D: x=2 If we plug x=2 into |x-6|=2x, we get: |2-6| = 2*2 |-4| = 4 4 = 4. Success! The correct answer is D.”
October 25, 2018
GMATGuruNY posted a reply to Tom drives from town A to town B, driving at a constant in the Problem Solving forum
“Let the distance between A and B = 120 miles. Since the 120-mile distance between A and B is twice the distance between B and C, the distance between B and C = 60 miles, implying that the total distance = 120+60 = 180 miles. Since the average speed for the 120-mile leg between A and B = 60 mph, ...”
October 25, 2018
GMATGuruNY posted a reply to gmat prep 2 in the Critical Reasoning forum
“The negation test is not recommended for Evaluate CRs. It can be applied to Assumption CRs and Inference CRs.”
October 24, 2018
GMATGuruNY posted a reply to Computer-based activities in the Critical Reasoning forum
“The answer choices are already phrased as statements. The OA is a statement that weakens the conclusion. OA: Computer owners in the United States predominately belong to a demographic group that have long been known to spend less time watching television. This statement indicates that a lack of ...”
October 24, 2018
GMATGuruNY posted a reply to Noelle walks from point A to point B at an average speed of in the Problem Solving forum
“Let the distance between A and B = the LCM of the two speeds = 5*6 = 30 kilometers, implying that the distance for the entire round trip = 60 kilometers. At a rate of 5 kph, the time to travel the 30 kilometers from A to B = d/r = 30/5 = 6 hours. At a rate of 6 kph, the time to travel the entire ...”
October 24, 2018
GMATGuruNY posted a reply to What is the median number of employees assigned per project in the Data Sufficiency forum
“In ascending order of EMPLOYEES PER PROJECT, let the projects be numbered 1 through 100: 1, 2, 3.....49, 50, 51, ....98, 99, 100. Projects 50 and 51 determine the MEDIAN number of employees: Question rephrased: How many employees are assigned to PROJECTS 50 and 51? Looking at the two ...”
October 24, 2018
GMATGuruNY posted a reply to Three photographers , Lisa, Mike and Norm, take photos of a in the Problem Solving forum
“The sum for Lisa and Mike is 50 less than the sum for Norm and Mike. Since Mike is common to both sums, the 50-photo difference must be yielded solely by Lisa and Norm. Implication: Lisa took 50 fewer photos than Norm. We can PLUG IN THE ANSWERS, which represent the number of photos taken by ...”
October 24, 2018
GMATGuruNY posted a reply to Circle ABCD in the diagram above is defined by the equation in the Problem Solving forum
“Circle ABCD: The equation for a circle with a center at the origin and a radius of r is x² + y² = r². The equation for circle ABCD is x² + y² = 5². Thus, circle ABCD has a radius of 5. Line EF: 3y = 4x + 25 y = (4/3)x + 25/3 Slope = 4/3. A radius drawn to a point of tangency forms ...”
October 24, 2018
GMATGuruNY posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum
“In many cases, similar or identical solutions are posted when two experts respond at virtually the same time, with the result that the second poster is not aware of the first. The time stamps for the two solutions here indicate that both solutions were posted at 11:45am.”
October 23, 2018
GMATGuruNY posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum
“Rates can be ADDED TOGETHER. 7 Machine As and 11 Machine Bs can produce 250 widgets per hour. 7A + 11B = 250 8 Machine As and 22 Machine Cs can produce 600 widgets per hour. 8A + 22C = 600 4A + 11C = 300 Adding together 7A + 11B = 250 and 4A + 11C = 300, we get: 11A + 11B + 11C = 550 A ...”
October 23, 2018
GMATGuruNY posted a reply to 25 integers are written on a board. Are there at least two in the Data Sufficiency forum
“The wording in Statement 1 does not convey a clear meaning: For every value in the list, if the value is increased by 1, the number of distinct values in the list does not change. Here, the term in red could convey to some test-takers that EVERY VALUE in the list is to be increased by 1. Not the ...”
October 23, 2018
GMATGuruNY posted a reply to The annual rent collected by a corporation from a certain in the Data Sufficiency forum
“Let the 1997 rent = 100. Increase in 1998 = (x/100)(100) = x. Thus, rent in 1998 = 100+x. Decrease in 1999 = (y/100)(100+x) = y + xy/100 For the rent to be greater in 1999 than in 1997, the increase in 1998 (x) must be greater than the decrease in 1999 (y + xy/100). Question stem, ...”
October 21, 2018
GMATGuruNY posted a reply to During a 3 year period, the profits of company X changed by in the Data Sufficiency forum
“Statement 1: If profits increase by $X from the first year to the second year, then they must increase by $0 from the second year to the third year, with the result that the increase in profits from the first year to the third year (X+0 = $X) is the same as the increase in profits from the first ...”
October 21, 2018
GMATGuruNY posted a reply to OG The estimated number of homeschooled students in the Problem Solving forum
“Percent greater or percent increase: (bigger value - smaller value)/(smaller value) * 100 Percent less or percent decrease: (bigger value - smaller value)/(bigger value) * 100”
October 21, 2018
GMATGuruNY posted a reply to Mark has fewer than 9 coins. Each coin is either a quarter in the Data Sufficiency forum
“Statement 1: 25Q + 10D = 170 5Q + 2D = 34 To minimize the number of coins, we must maximize the value of Q. If Q=6, then D=2, with the result that 5Q + 2D = (5*6) + (2*2) = 34. In this case, the total number of coins = 6+2 = 8. If the value of Q decreases, then the total number of coins will ...”
October 20, 2018
GMATGuruNY posted a reply to doubt 3 in the Sentence Correction forum
“having + VERBed is a viable construction. An introductory HAVING + VERBed modifier implies PRIOR ACTION: an action completed before the main verb. HAVING FINISHED his dessert, John LEFT the table. Here, HAVING FINISHED implies PRIOR ACTION -- an action completed before John LEFT the table. ...”
October 20, 2018
GMATGuruNY posted a reply to All attendees at a university gathering are faculty or in the Data Sufficiency forum
“Neither statement offers any information about the number of attendees who are alumni. Thus, the two statements combined are INSUFFICIENT. The correct answer is E.”
October 20, 2018
GMATGuruNY posted a reply to If n is an integer, which of the following must be divisible in the Problem Solving forum
“Test n=0. A --> n³ - 4n = 0³ - (4*0) = 0 B --> n³ + 4n = 0³ + (4*0) = 0 C --> n² + 1 = 0² + 1 = 1 D --> n² - 1 = 0² - 1 = -1 E --> n² - 4 = 0² - 4 = -4 Only the options in green yield a multiple of 3. Eliminate C, D and E. Test n=1 in the remaining answer ...”
October 20, 2018
GMATGuruNY posted a reply to At a certain industrial manufacturer, an open tank contains in the Problem Solving forum
“Since 6% of the 1000-gallon tank is fluorine, the amount of fluorine = (6/100)(1000) = 60 gallons. Since the total volume decreases at a rate of 10 gallons per day for 25 days, the decrease in the total volume = 10*25 = 250 gallons. Remaining total volume = 1000-250 = 750 gallons. Since 60 of the ...”
October 20, 2018
GMATGuruNY posted a reply to Is 1+x+x^2+x^3+x^4+x^5+x^6 < 1/(1-x)? in the Data Sufficiency forum
“CRITICAL POINTS in an equality occur when the two sides are EQUAL or the inequality is undefined. Here, the two statements provide the critical points for the inequality in the prompt: When x=0, the two sides are equal. When x=1, the inequality is undefined. To determine the range(s) where the ...”
October 20, 2018
GMATGuruNY posted a reply to Did Jeff record more sales revenue this month than Dan did? in the Data Sufficiency forum
“Statement 1: For every $100 commission that Dan earns, Jeff earns $120 in commission. Since the commission rates for Dan and Jeff are unknown, no way to determine whether Jeff recorded more sales revenue than Dan. INSUFFICIENT. Statement 2: Since Jeff''s sales and Dan''s sales can be any ...”
October 19, 2018
GMATGuruNY posted a reply to If a rectangle’s length is a+b and its area is (1/a)+(1/b) in the Problem Solving forum
“Let a=b=0.5, implying that the rectangle''s length = a+b = 0.5+0.5 = 1 and that its area = (1/0.5) + (1/0.5) = (10/5) + (10/5) = 2+2 = 4. Since the rectangle has an area of 4 and a length of 1, its width = 4. The correct answer must yield a value of 4 when a=b=0.5. Only E works: 1/ab = 1/(0.5 * ...”
October 19, 2018
GMATGuruNY posted a reply to When positive integer N is divided by positive integer J, in the Problem Solving forum
“N/J = 134.08 = 13408/100 = 3352/25. The resulting ratio indicates that N must be multiple of 3352 and that J must be a multiple of 25. Of the five answer choices, only E is a multiple of 25. The correct answer is E.”
October 19, 2018
GMATGuruNY posted a reply to A container contains 4 red marbles and 8 blue marbles. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of blue marbles in the second container. When the correct answer is plugged in, the probability of selecting 2 red marbles OR 2 blue marbles = 1/2. B: 4 blue marbles, implying a total of 10 marbles in the second container Case1: 2 red ...”
October 19, 2018
GMATGuruNY posted a reply to Two printing presses begin printing currency at the same in the Problem Solving forum
“Since F produces 1000 5-dollar bills each minute, the dollar amount produced by F each minute = 1000*5 = $5000. Since T produces 200 20-dollar bills each minute, the dollar amount produced by T each minute = 200*20 = $4000. Thus, every minute F surpasses T by $1000. Since F surpasses T by $1000 ...”
October 18, 2018
GMATGuruNY posted a reply to Brian purchased a bouquet of 40 flowers for his mother for in the Problem Solving forum
“= We can PLUG IN THE ANSWERS, which represent the number of tulips. When the correct answer is plugged in, the total cost = $48. D: 24 tulips, implying 16 roses, for a total of 40 flowers Since each of the 24 tulips costs $1, and each of the 16 roses costs $1.50, we get: Total cost = (24*1) ...”
October 18, 2018
GMATGuruNY posted a reply to A certain NYC taxi driver has decided to start charging a in the Problem Solving forum
“Let r=100 cents. For 3 people, the cost per mile = 3*100 = 300 cents = 3 dollars. Let x = 2 miles. Regular cost for 3 people to travel 2 miles = 3*2 = 6 dollars. With a 50% discount, the cost in dollars = 3. This is the target. Plug x=2 and r=100 into the answers to see which yields the ...”
October 16, 2018
GMATGuruNY posted a reply to (1-1/10)(1-1/11)(1-1/12)…(1-1/100) =? in the Problem Solving forum
“(1-1/10)(1-1/11)(1-1/12)…(1-1/99)(1-1/100) = (9/10)(10/11)(11/12)....(98/99)(99/100). The values in blue all cancel out, leaving only the values in red: 9/100. The correct answer is C.”
October 16, 2018
GMATGuruNY posted a reply to A rectangular garden is to be twice as long as it is wide. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the length. When the correct answer is plugged in, perimeter = 360. B: 140 Since the length is twice the width, W = 70, with the result that the perimeter = 140+140+70+70 = 420. Since the perimeter is too great, a SMALLER answer choice is needed. ...”
October 16, 2018
GMATGuruNY posted a reply to Is the sum of 7 different positive integers greater than or in the Data Sufficiency forum
“Statement 1: Least possible case: 1+2+3+9+10+11+12 = 48. Since the least possible case is greater than or equal to 48, the answer to the question stem is YES. SUFFICIENT. Statement 2: Least possible case: 1+2+3+4+5+6+12 = 33. Greatest possible case: 6+7+8+9+10+11+12 = 63. Since the answer ...”
October 16, 2018
GMATGuruNY posted a reply to If x, y, and z are all nonzero numbers, and x = y + z, which in the Problem Solving forum
“x = y + z is valid if x=2, y=1 and z=1. The correct answer must yield a value of 1 when x=2, y=1 and z=1. Only E works: (x-z)/y = (2-1)/1 = 1. The correct answer is E.”
October 16, 2018
GMATGuruNY posted a reply to If |x+1|=2|x-1|, x=? in the Data Sufficiency forum
“Case 1: Signs unchanged x+1 = 2(x-1) x+1 = 2x-2 3 = x Case 2: Signs changed on ONE SIDE -x-1 = 2(x-1) -x-1 = 2x-2 1 = 3x 1/3 = x Resulting solutions: x=3 or x=1/3 Statement 1: Since x < 1, only x=1/3 is a viable solution. SUFFICIENT. Statement 2: Since x>0, both x=1/3 ...”
October 15, 2018
GMATGuruNY posted a reply to Lindsay can paint 1/x of a certain room in one hour. If in the Problem Solving forum
“Let the room = 20 units. Let x = 4. Since Lindsay paints 1/x of the room in 1 hour, Lindsay''s rate = (1/4) * 20 = 5 units per hour. Since Lindsay and Joseph paint the entire room in 1 hour, their combined rate = 20 units per hour. Thus, Joseph''s rate = (combined rate) - (Lindsay''s rate) ...”
October 15, 2018
GMATGuruNY posted a reply to The principal feature of the redesigned checks is a series o in the Sentence Correction forum
“Generally, a COMMA + VERBing modifier serves to modify the nearest preceding action and the agent of this action. C: instructions that...will help merchants confirm a check''s authenticity, by including reminders to watch the endorsement. .Here, COMMA + by including seems to modify merchants ...”
October 15, 2018
GMATGuruNY posted a reply to What is the remainder if 7^10 is divided by 100? in the Problem Solving forum
“When a positive integer is divided by 100, the remainder is yielded by the last two digits: 123/100 = 1 R23 548/100 = 5 R48 692/100 = 6 R92 Thus: The remainder when 7¹⁰ is divided by 100 is equal to the last two digits of 7¹⁰. Calculate the last two digits for consecutive powers of 7 ...”
October 14, 2018
GMATGuruNY posted a reply to Alice, Barbara, and Cynia work on identical tasks at differe in the Data Sufficiency forum
“TIME and RATE have a reciprocal relationship. Statement 1: The time ratio for Barbara and Alice = (14 hours)/(21 hours). The rate ratio for Barbara and Alice is equal to the reciprocal of the time ratio: (B''s rate)/(A''s rate) = 21/14 = 3/2. Let B = 3 units per hour and A = 2 units per ...”
October 13, 2018
GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum
“Let James'' rate = 3 mph. James started from his home and drove eastwards at a constant speed. Exactly 90 minutes after James stated from his home, his brother Patrick started from the same point and drove in the same direction as James did at a different constant speed. Patrick overtook James ...”
October 13, 2018
GMATGuruNY posted a reply to A certain club has 10 members, including Harry. One of the 1 in the Problem Solving forum
“Each of the 10 members has an EQUAL chance of being elected secretary. P(Harry is elected secretary) = 1/10. Each of the 10 members has an EQUAL chance of being elected treasurer. P(Harry is elected treasurer) = 1/10. Since EITHER outcome is favorable, we ADD the fractions: 1/10 + 1/10 = 2/10 = ...”
October 13, 2018
GMATGuruNY posted a reply to Challenge question: What is the sum of all in the Problem Solving forum
“x^(2/3) - x^(1/3) - 2 = 4 x^(2/3) - x^(1/3) - 6 = 0 D.”
October 12, 2018
October 12, 2018
GMATGuruNY posted a reply to Hard Assumption - Manhattan in the Critical Reasoning forum
“The conclusion is constrained to the case at hand: Of the 10 babies recently placed with parents, 8 were given to friends of the staff. The assumption is that the premise (the parents given babies -- including the 8 friends --all far surpassed the agency''s criteria) is sufficient to prove the ...”
October 11, 2018
GMATGuruNY posted a reply to If every boy in a kindergarten class buys a soda and every in the Problem Solving forum
“Let: b = the number of boys g = the number of girls s = the number of cents for each soda j = the number of cents for each juice box Note: All of the values above must be POSITIVE INTEGERS. Case One: If every boy in a kindergarten class buys a soda and every girl in the same class buys a ...”
October 11, 2018
GMATGuruNY posted a reply to Julie opened a lemonade stand and sold lemonade in two in the Data Sufficiency forum
“Let X = the number of 52¢ lemonades and Y = the number of 58¢ lemonades. Since the question stem asks for the number of 52¢ lemonades, we get: What is the value of X? Statement 1: X+Y = 9 Since X can be any value between 0 and 9, inclusive, INSUFFICIENT. Statement 2: 52X + 58Y = 492 ...”
October 11, 2018
GMATGuruNY posted a reply to For the students in a Physical Fitness Class Section #1, the in the Data Sufficiency forum
“Range = highest - lowest. Thus: Lowest = highest - range. In Section 1, lowest = highest - range = X-R. In Section 2, lowest = highest - range = Y-S. If the lowest weight in Section 1 is greater than the lowest weight in Section 2, we get: X-R > Y-S X+S > Y+R. Question ...”
October 11, 2018
GMATGuruNY posted a reply to Angela’s grade was in the 90th percentile out of 80 grades in the Problem Solving forum
“Percentile means the percentage below: (total below)/(total grades) * 100. Angela''s 80-student class: Since Angela''s grade was in the 90th percentile, 90% of the grades were below Angela''s: (90/100)(80) = 72. 100-student class: Since 19 grades were higher than Angela''s, the remaining ...”
October 10, 2018
GMATGuruNY posted a reply to There are 5 cars to be displayed in 5 parking spaces with in the Problem Solving forum
“Alternate approach: The 3 red cars must occupy a combination of 3 spaces. From 5 spaces, the number of ways to choose a combination of 3 for the red cars = 5C3 = (5*4*3)/(3*2*1) = 10. Number of options for the blue car = 2. (Either of the 2 remaining spaces.) Number of options for the yellow ...”
October 10, 2018
GMATGuruNY posted a reply to Hard Assumption - Manhattan in the Critical Reasoning forum
“Premise: All of the applicants given babies far surpassed the adoption criteria. Conclusion: In placing 8 of the 10 babies with friends, the staff was not guilty of favoritism. Apply the NEGATION TEST. When the correct answer is negated, the conclusion will be invalidated. B, negated: Of ...”
October 10, 2018
GMATGuruNY posted a reply to A group of medical interns at Bohemus Medical School want to in the Problem Solving forum
“In other words: How many ways can 5 girls and 5 guys be divided into pairs, if each pair must consist of one girl and one guy? Number of options for the first girl = 5. (Any of the 5 guys.) Number of options for the second girl = 4. (Any of the 4 remaining guys). Number of options for the ...”
October 9, 2018
GMATGuruNY posted a reply to If x, y, and z are positive numbers, Is z between x and y? in the Data Sufficiency forum
“Statement 1: x < 2z < y Let x=2 and y=10. In this case: 2 < 2z < 10 1 < z < 5. If z=4, then it is between x=2 and y=10. If z=1.5, then it is not between x=2 and y=10. INSUFFICIENT. Statement 2: 2x < z < 2y Let x=2 and y=10. In this case: 2*2 < z ...”
October 9, 2018
GMATGuruNY posted a reply to If s is an integer between 0 and 10, is t less than the av in the Data Sufficiency forum
“The average of s and 10 lies HALFWAY between s and 10 on the number line: s------------AVERAGE------------10 Statement 1: Since t closer to 10 than to s, t must be greater than the average of s and 10, as shown here: s-----------AVERAGE---t----------10 Thus, the answer to the question stem is ...”
October 9, 2018
GMATGuruNY posted a reply to A group of 10 people consists of 3 married couples and 4 si in the Problem Solving forum
“Good committees = total committees - bad committees. Total committees: From 10 people, the number of ways to choose 4 = 10C4 = (10*9*8*7)/(4*3*2*1) = 210. Bad committees: Since a good committee includes at most 1 married couple, a bad committee is composed of 2 married couples. From 3 ...”
October 9, 2018
GMATGuruNY posted a reply to Problem solving: Difficulty level: 700, Source: Princeton in the Problem Solving forum
“For any evenly spaced set: sum = (number)(median) We can PLUG IN THE ANSWERS, which represent the sum. Since the number of integers can be 5 or 7, the sum must be a multiple of both 5 and 7. Eliminate A, which is not divisible by 5. Eliminate D, which is not divisible by 7. The equation in ...”
October 7, 2018
GMATGuruNY posted a reply to Health insurance Plan A requires the insured to pay $1000 or in the Problem Solving forum
“THE INSURED is the person covered by the insurance. Plan A: If $1000 is LESS than 50% of the cost level, then THE INSURED pays $1000, and PLAN A pays the remainder. If $1000 is MORE than 50% of the cost level, then THE INSURED pays 50% of the cost level, and PLAN A pays the remainder. Plan ...”
October 6, 2018
GMATGuruNY posted a reply to John tossed a fair coin 3 times. What is the probability in the Problem Solving forum
“P(TTH) = 1/2 * 1/2 * 1/2 = 1/8. Since H can occur on the 1st, 2nd or 3rd flip, we multiply by 3: 3*(1/8) = 3/8. The correct answer is C.”
October 6, 2018
GMATGuruNY posted a reply to Mixture Problem DS in the Data Sufficiency forum
“Yes -- each statement conveys the same information, since doubling the total volume is the equivalent of reducing the acid concentration by 1/2.”
October 6, 2018
GMATGuruNY posted a reply to The value of a share was 25% less in the 2nd quarter over in the Problem Solving forum
“Let the 1st-quarter value = 100. Since 2nd-quarter value is 25% less, the 2nd-quarter value = 100 - (25% of 100) = 100 - 25 = 75. Since the 3rd-quarter value is 20% more than the 2nd-quarter value, the 3rd-quarter value = 75 + (20% of 75) = 75 + 15 = 90. Since the 4th-quarter value must equal 120 ...”
October 6, 2018
GMATGuruNY posted a reply to Mixture Problem DS in the Data Sufficiency forum
“Statement 1 indicates that 80 grams of water are added to the 80 grams of original solution, DOUBLING the total volume from 80 grams to 160 grams Statement 2 indicates that the added water reduces the acid concentration by 1/2. Doubling the total volume will reduce the acid concentration by 1/2 ...”
October 6, 2018
GMATGuruNY posted a reply to Each year for 4 years, a farmer increased the number of in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the original number of trees. Since the number of trees increases by 1/4 each year, the correct answer must be a multiple of 4. The last 2 digits of a multiple of 4 must themselves form a multiple of 4. Eliminate A (1250) and C (2250), since 50 is ...”
October 5, 2018
GMATGuruNY posted a reply to A chessboard is an 8×8 array of identically sized squares. in the Problem Solving forum
“Case 1: Every 6-block rectangle with a base of 2 and a height of 3 yields 4 possible L-shapes: https://i.postimg.cc/1gJCfb5J/chessboard_L_shape_1.png Chessboard: https://i.postimg.cc/LYJThXW8/chessboard_whole.png The base for the 6-block rectangle shown above can appear in rows 1 through 6, ...”
October 5, 2018
GMATGuruNY posted a reply to Amit and Ian paint a wall in alternating shifts. First Amit in the Problem Solving forum
“During each of Amit''s 4 shifts, he paints 1/2 of the room, leaving 1/2 the room unpainted. Since 1/2 of the room is left unpainted FOUR TIMES, the total fraction left unpainted as a result of Amit''s 4 shifts = (1/2)⁴. Since Ian works after each of Amit''s first 3 shifts, Ian paints a total ...”
October 5, 2018
GMATGuruNY posted a reply to A thin piece of wire 40 meters long is cut into two pieces. in the Problem Solving forum
“Since the answer choices are in terms of a variable -- the value of r -- we can PLUG IN. Let the ENTIRE WIRE be used to form the square. Then: Perimeter of the square = 40. Side = 10. Area = 100. Circle area + square area = 0 + 100 = 100. This is our target. Since the circle has no ...”
October 4, 2018
GMATGuruNY posted a reply to If x and y are positive integers, is x^2*y^2 even ? in the Data Sufficiency forum
“x²y² will be even unless both x and y are ODD. Question stem, rephrased: Are x and y both odd? Statement 1: x+5 is prime number greater than 2 and thus must be ODD. Implication: x+5 = ODD x = ODD - 5 = ODD - ODD = EVEN. Since x is even, x and y cannot both be odd. SUFFICIENT. ...”
October 4, 2018
GMATGuruNY posted a reply to A hiker walking at a constant rate of 4 miles per hour is in the Problem Solving forum
“Rate and time have a RECIPROCAL RELATIONSHIP. The RATE RATIO for the hiker and cyclist = 4 mph : 20 mph = 1:5. Thus: The TIME RATIO for the hiker and cyclist = the reciprocal of the rate ratio = 5:1. Implication: The hiker will take 5 TIMES AS LONG as the cyclist to travel the same ...”
October 4, 2018
GMATGuruNY posted a reply to How many ounces of water must be added to 10 ounces of 3 % in the Problem Solving forum
“Alcohol percentage in the original solution: 3%. Alcohol percentage in the added water: 0%. Alcohol percentage in the mixture: 1%. Let S = the original solution and W = the added water. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: ...”
October 3, 2018
GMATGuruNY posted a reply to Vivian drives to her sister's house and back. She takes the in the Problem Solving forum
“When the same distance is traveled at two different speeds, the average speed for the entire trip will be a bit LESS than the average of the two speeds. Since (70+50)/2 = 60, the average speed for Vivian''s''s entire trip must be a bit less than 60. The correct answer is B.”
October 3, 2018
GMATGuruNY posted a reply to Tom’s Mom is five times as old as him. In 6 years, Tom’ in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represents Tom''s current age. When the correct answer is plugged in, Mom''s age in 6 years will be 3 times Tom''s age in 6 years. D: Tom = 6 Since Mom is currently 5 times as old as Tom, Mom = 5*6 = 30. Tom''s age in 6 years = 6+6 = 12. ...”
October 3, 2018
GMATGuruNY posted a reply to If 3 different numbers are selected from the first 8 prime n in the Problem Solving forum
“First 8 prime numbers: 2, 3, 5, 7, 11, 13, 17, 19. The sum will be even if 2 is among the three numbers selected, with the result that the sum = EVEN PRIME + ODD PRIME + ODD PRIME = EVEN. Since 3 NUMBERS are selected from 8 OPTIONS, the probability that 2 will be among the three numbers selected = ...”
October 2, 2018
GMATGuruNY posted a reply to In a certain office, 50 percent of the employees are college in the Data Sufficiency forum
“Let T = the total number of employees. Since 60% of the employees are over 40, we get: Over 40 = 0.6T 30% of those over 40 -- in other words, 30% of the expression in blue -- have master''s degrees. Thus: Over 40 with master''s = 0.3(0.6T). To calculate the value of the expression in ...”
October 2, 2018
GMATGuruNY posted a reply to On a 20 mile course, Pat bicycled at an average rate of 30 in the Problem Solving forum
“Since Pat travels at 30 miles per hour for the first 12 minutes -- the equivalent of 1/5 hour -- the distance traveled in the first 12 minutes = (30)(1/5) = 6 miles. Since the remaining 14 miles are traveled at 8 miles per hour, the time to travel the remaining 14 miles = 14/8 = 7/4 hours = 1 hour ...”
October 2, 2018
GMATGuruNY posted a reply to 190 students go to a school bake sale. 95 buy a chocolate in the Problem Solving forum
“Total = Group 1 + Group 2 - Both + Neither Here: Total = 190. Group 1 = 95 who buy chocolate chip. Group 2 = 75 who buy peanut butter. Plugging these values into the equation above, we get: 190 = 95 + 75 - Both + Neither 20 + Both = Neither Neither = 20 + Both. To minimize the value of ...”
October 2, 2018
GMATGuruNY posted a reply to Is x^3-x>0? in the Data Sufficiency forum
“Question stem, rephrased: Is x³ > x? Statement 1: x > 1 When a positive value greater than 1 is cubed, the result is greater than the original number: x=2 --> 2³ > 2 x=3 --> 3³ > 3 x=4 --> 4³ > 4 In every case, x³ > x. Thus, the answer to the rephrased ...”
October 2, 2018
GMATGuruNY posted a reply to The greatest common factor of 16 and the positive integer n in the Problem Solving forum
“The greatest common factor of 16 and the positive integer n is 4, and the greatest common factor of n and 45 is 3. Draw a VENN DIGRAM showing where the prime factors of n, 16 and 45 overlap: https://i.postimg.cc/xkyNCFg7/GCF_Venn_n_16_and_45.jpg The diagram implies the following: Since n and ...”
October 2, 2018
GMATGuruNY posted a reply to Five letters A, P, P, L and E are listed in a row. How many in the Problem Solving forum
“Good arrangements = total arrangements - bad arrangements. Total arrangements: Number of ways to arrange 5 elements = 5!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of identical elements can be ARRANGED. The reason: When the ...”
October 1, 2018
GMATGuruNY posted a reply to If a, b, c, d, e are consecutive positive integers such that in the Problem Solving forum
“For any set of consecutive integers, average = median. Let the five integers = 1, 2, 3, 4, 5. Average of 2, 3, 4 and 5 = 3.5. Average of 1, 2, 3, and 4 = 2.5. Difference between the averages = 3.5 - 2.5 = 1. The correct answer is D.”
September 30, 2018
GMATGuruNY posted a reply to If a, b, c, d, e are integers such that a<b<c<d< in the Data Sufficiency forum
“Statement 1: For any set of consecutive integers, average = median. Case 1: 1, 2, 3, 4, 5 Average of 2, 3, 4 and 5 = 3.5. Average of 1, 2, 3, and 4 = 2.5. Difference between the averages = 3.5 - 2.5 = 1. Case 2: 2, 3, 4, 5, 6 Average of 3, 4, 5, and 6 = 4.5. Average of 2, 3, 4 and 5 = ...”
September 30, 2018
GMATGuruNY posted a reply to If x is the greatest common factor of 36 and 96, what is the in the Problem Solving forum
“36 = 2*2*3*3 96 = 2*2*2*2*2*3 GCF = the product of the factors in blue = 2*2*3 = 12. Sum of the digits = 1+2 = 3. The correct answer is B.”
September 30, 2018
GMATGuruNY posted a reply to Bob invested $2000 in fund A and $1000 in fund B. Over the in the Problem Solving forum
“Fund A after 2 years: 2000 + (10% of 2000) + (2)(1% of 2000) = 2000 + 200 + 2(20) = 2240. Fund B after 1 year: 1000 + (30% of 1000) = 1000 + 300 = 1300. Fund B after 2 years: 1300 + (30% of 1300) = 1300 + 390 = 1690. Difference after two years: 2240 - 1690 = 550. The correct answer is ...”
September 30, 2018
GMATGuruNY posted a reply to If a photocopier makes 2 copies in 1313 second, then, at the in the Problem Solving forum
“Using ratios, convert 4 minutes into copies: (4 minutes) * (60 seconds)/(1 minute) * (2 copies)/(1/3 second) = 1440 copies. The correct answer is E.”
September 30, 2018
GMATGuruNY posted a reply to Lindsay can paint 1/x of a certain room in 20 minutes. What in the Problem Solving forum
“Let the room = 20 units. Let x = 4. Since Lindsay paints 1/x of the room in 20 minutes -- the equivalent of 1/3 hour -- Lindsay''s rate = (1/4) * 20 = 5 units per 1/3 hour = 15 units per hour. Since Lindsay and Joseph paint the entire room in 1 hour, their combined rate = 20 units per hour. ...”
September 29, 2018
GMATGuruNY posted a reply to 50% of students' study science and 30% of science students in the Problem Solving forum
“Let the total number of students = 100. Since 50% of the students study science, the number of science students = (50/100)(100) = 50, implying that the number of non-science students = 100-50 = 50. Since 30% of the 50 science students score more than 80%, the number of science students who ...”
September 29, 2018
GMATGuruNY posted a reply to A garden center sells a certain grass seed in 5-pound bags in the Problem Solving forum
“5-pound bags = ($13.85)/5 ≈ $3 per pound. 10-pound bags = ($20.43)/10 = more than $2 per pound. 25-pound bags = ($32.25)/25 = less than $1.50 per pound. To minimize the cost, we must maximize the number of 25-pound bags, which offer seed at the lowest price per pound. Two 25-pound bags = 50 ...”
September 29, 2018
GMATGuruNY posted a reply to Which of the following equations is NOT equivalent to in the Problem Solving forum
“If we plug y=-3 into 4x² = y²-9, we get: 4x² = (-3)² - 9 4x² = 0 x = 0. Test x=0 and y=-3 in the answer choices. When the question stem includes the phrase which of the following, the correct answer is likely to be D or E. D: 2x = y-3 Plugging in x=0 and y=-3, we get: 2*0 = -3-3 0 = ...”
September 28, 2018
GMATGuruNY posted a reply to If non- negative integers n & p are not both odd, in the Problem Solving forum
“If n=p=0, options A, B, C and D each yield a even value, indicating that these options do NOT have to be odd. Eliminate A, B, C and D. The correct answer is E.”
September 28, 2018
GMATGuruNY posted a reply to Is |x+y|<|x|+|y|? in the Data Sufficiency forum
“Since an absolute value cannot be negative, both sides of the question stem are NONNEGATIVE, enabling us to safely square the inequality: (|x+y|)²< (|x|+|y|)² x² + y² + 2xy < x² + y² + 2|x||y| xy < |xy| The resulting inequality is valid only if x and y have DIFFERENT SIGNS. ...”
September 28, 2018
GMATGuruNY posted a reply to The shaded portion of the rectangular lot shown above in the Problem Solving forum
“ALWAYS KEEP YOUR EYES ON THE ANSWER CHOICES. C, D and E imply that the flower bed is probably a 6-8-10 triangle in which y=6, x = y+2 = 6+2 = 8, and z=10. Check whether this triangle satisfies the condition that the flower bed has an area of 24 square yards: Area of a 6-8-10 triangle = ...”
September 27, 2018
GMATGuruNY posted a reply to Anna wants to distribute chocolates among her four children in the Problem Solving forum
“Let the total number of chocolates = the LCM of the four denominators 2, 5, 6 and 12 = 60. Number of chocolates given to the four children: (1/2)(60) = 30 (1/5)(60) = 12 (1/6)(60) = 10 (1/12)(60) = 5 Total number of chocolates = 30+12+10+5 = 57. The correct answer is C.”
September 27, 2018
GMATGuruNY posted a reply to In 2004, 2,400 condos sold, 15% of the total housing units in the Problem Solving forum
“Of the units sold, non-condos constitute 85% = 85/100 = 17/20. Implication: Of every 20 units sold, 17 are non-condos, with the result that the number of non-condos must be a multiple of 17. A. 16000 B. 13600 C. 12400 D. 11200 E. 8600 Only the portion in green is a multiple of 17: ...”
September 27, 2018
GMATGuruNY posted a reply to If the probability of Ronaldo will score at least 3 goals in in the Problem Solving forum
“Let G = at least 3 goals and NG = not at least 3 goals. Let W = win the match and NW = not win the match. Use a DOUBLE-MATRIX to organize the data: https://i.postimg.cc/JHLj6Tyr/matrix_goals_wins_0.png The probability that Ronaldo will score at least 3 goals in the match is 0.59. The ...”
September 27, 2018
GMATGuruNY posted a reply to A set of numbers has an average of 50. If the largest elemen in the Problem Solving forum
“Let S = the smallest number of L = the largest number. Since the largest number is 4 more than 3 times the smallest number, we get: L = 3S + 4 L-4 = 3S (L-4)/3 = S. Since the average is 50 -- and the numbers are not all the same -- S must be LESS THAN 50, while L must be greater than 50. ...”
September 26, 2018
GMATGuruNY posted a reply to What is the sum of the solutions of the equation (x-1)^2=|x- in the Problem Solving forum
“If we replace x-1 with a, we get: a² = |a|. The resulting equation is valid only if a -- in other words, the value of x-1 -- is equal to -1, 0, or 1: x-1 = -1 --> x=0 x-1 = 0 ---> x=1 x-1 = 1 ---> x=2 Sum of the solutions = 0+1+2 = 3. The correct answer is E.”
September 26, 2018
GMATGuruNY posted a reply to If H = [(x^3) - 6(x^2) - x + 30] / (x-5)and x ≠ 5, then H in the Problem Solving forum
“Let x=0, with the result that H = 30/-5 = -6. Now plug x=0 in the answers to see which yields a value of -6. Only A works: x² - x - 6 = 0² - 0 - 6 = -6. The correct answer is A.”
September 26, 2018
GMATGuruNY posted a reply to Robin split a total of $24,000 between 2 investments, X and in the Data Sufficiency forum
“Statement 1: Test one case that also satisfies Statement 2. Case 1: X = 5% and Y = 7% For 5% interest and 7% percent interest to yield the same dollar amount, $7 must be invested at 5% interest for every $5 invested at 7% interest: X --> $7(0.05) = $0.35. Y --> $5(0.07) = $0.35. Thus: ...”
September 25, 2018
GMATGuruNY posted a reply to In how many ways four men, two women and one child can sit a in the Problem Solving forum
“Once the child has been placed at the table: Number of ways to arrange the 2 women in the 2 seats adjacent to the child = 2! = 2. Number of ways to arrange the 4 men in the remaining 4 seats = 4! = 24. To combine these options, we multiply: 2*24 = 48. The correct answer is C.”
September 24, 2018
GMATGuruNY posted a reply to W, X, Y and Z each represent a different number. If the sum in the Problem Solving forum
“Sum of all 4 rows = 3 + 6 + 9 + 0 = 18. Sum of all 4 columns = -2 + 7 + n + 5 = n + 10. The values in blue must be EQUAL, since each represents the sum of all 16 values in the table. Thus: n+10 = 18 n=8. The correct answer is C.”
September 24, 2018
GMATGuruNY posted a reply to How many 3 digit numbers can we make such that two of the in the Problem Solving forum
“Number of digit options for the repeated digit = 9. (Any digit but 0.) Number of digit options for the non-repeated digit = 8. (Any digit but 0 and the digit already used.) Number of position options for the non-repeated digit = 3. (The hundreds place, the tens place, or the units place.) To ...”
September 24, 2018
GMATGuruNY posted a reply to Is 10m > 5n - k? in the Data Sufficiency forum
“Statement 1: n=2m Substituting n=2m into 10m > 5n-k, we get: 10m > 5(2m) - k ? 10m > 10m - k ? 0 > -k ? k > 0 ? No way to determine whether k>0. INSUFFICIENT. Statement 2: |k| = -k This equation is valid only if k≤0. No information about m or n. INSUFFICIENT. ...”
September 23, 2018
GMATGuruNY posted a reply to Machine A and Machine B can produce 1 widget in 3 hours work in the Problem Solving forum
“Algebra: Machine A and Machine B can produce 1 widget in 3 hours working together at their respective constant rates. (A+B)(3) = 1 widget. If Machine A''s speed were doubled, the two machines could produce 1 widget in 2 hours working together at their respective rates. (2A+B)(2) = 1 widget. ...”
September 23, 2018
GMATGuruNY posted a reply to Machine A and Machine B can produce 1 widget in 3 hours work in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent A''s time to produce 1 widget. Since A and B working together take 3 hours to produce 1 widget, A working alone must take MORE than 3 hours. Eliminate A, B and C. Let the value of each widget = 30 units. Since A and B together take 3 hours to produce ...”
September 23, 2018
GMATGuruNY posted a reply to In an office that employs 120 people, m% of the employees in the Data Sufficiency forum
“Use a DOUBLE-MATRIX to organize the data. Statements combined: Case 1: m=25% and c=25% Total number of males = (25/100)(120) = 30. Total number of custodial employees = (25/100)(120) = 30. The following matrix is yielded: https://i.postimg.cc/H88Lq5zN/matrix_custodial_1.png In this case, ...”
September 22, 2018
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