GMATGuruNY posted a reply to If a and b are positive integers in the Data Sufficiency forum
“It is a good idea to know the following: 1/11 = 0.090909... Thus: 9/11 = 9(0.090909...) = 0.818181...”
Yesterday
GMATGuruNY posted a reply to At 8am on Thursday, two workers, A and B, each start working in the Problem Solving forum
“Worker A takes two 8-hour days to produce a lamp, for a total of 16 hours. Since Worker B finishes sometime Friday morning, B takes between 8 and 12 hours to produce a lamp. Let each lamp = 48 units. A''s rate = w/t = 48/16 = 3 unit per hour. If B takes 8 hours to produce a lamp, B''s rate = ...”
Yesterday
GMATGuruNY posted a reply to Is k^2 odd? in the Data Sufficiency forum
“The median for an EVEN NUMBER of consecutive integers will always be a NON-INTEGER: 1, 2 --> median = 1.5 1, 2, 3, 4 --> median = 2.5. 1, 2, 3, 4, 5, 6 --> median = 3.5. The median for an ODD NUMBER of consecutive integers will always be an INTEGER: 1, 2, 3 --> median = 2. 1, 2, ...”
Yesterday
GMATGuruNY posted a reply to Is x - y > 0? in the Data Sufficiency forum
“Question stem, rephrased: Is x > y? Statement 1: Case 1: y=0, implying that x > |0| and thus x > 0 Case 2: y=1, implying that x > |1| and thus x > 1 Case 3: y=-1, implying that x > |-1| and thus x > 1 Case 4: y=10, implying that x > |10| and thus x > 10 Case 5: ...”
Yesterday
GMATGuruNY posted a reply to If x and y are positive integers, does x/y = 7/9? in the Data Sufficiency forum
“Statement 1: Test whether it''s possible that x/y = 7/9 when x=103: 103/y = 7/9 7y = 103*9 y = (103*9)/7 = noninteger. Since y must be a positive integer, it is not possible that x/y = 7/9. Thus, the answer to the question stem is NO. SUFFICIENT. To compare fractions: 1. Multiply the ...”
Yesterday
GMATGuruNY posted a reply to In 2003, the number of girls attending Jefferson High in the Problem Solving forum
“Test the SMALLEST POSSIBLE CASE. Since both populations increase by 20% = 1/5, the original number of boys and the original number of girls must each be a multiple of 5. Since in 2003 there must be an equal number of boys and girls, the smallest possible case is as follows: 2003: boys = 5 and ...”
Yesterday
GMATGuruNY posted a reply to Much like the belief that the world is flat, challenged by in the Sentence Correction forum
“OA: Much like the belief that the world is flat, challenged by Galileo, there are currently widely-held hypotheses. Here, COMMA + challenged is incorrectly preceded by the clause in red. A COMMA + VERBed modifier must be preceded by a NOUN or NOUN PHRASE. Also, the referent for an introductory ...”
Yesterday
GMATGuruNY posted a reply to Low temperature in the Sentence Correction forum
“The conclusion in red is not necessarily true. and may serve to connect concurrent actions. Mary was sitting and reading. Here, the two actions in blue are performed at the same time.”
Yesterday
GMATGuruNY posted a reply to How many 4-digit integers have the form abcd, where b is eve in the Problem Solving forum
“Careful! The cases above are invalid because they violate the condition that b must be even.”
Yesterday
GMATGuruNY posted a reply to "A" and "B" run around a circular track in the Problem Solving forum
“Middle of the 5th round = 4.5 laps. (4 full laps + half of the 5th lap.) Since A''s rate = 70 seconds per lap, the time for A to complete 4.5 laps = (total number of laps)(number of seconds per lap) = (4.5)(70) = 315 seconds. We can PLUG IN THE ANSWERS, which represent the number of seconds for ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“For the 3 words to be switched on simultaneously, each must reach the END OF ITS RESPECTIVE ON-OFF CYCLE. On-off cycle for RON: (3 seconds on) + (47/6 seconds off) = 18/6 + 47/6 = 65/6 seconds. On-off cycle for AND: (3 seconds on) + (4/3 seconds off) = 18/6 + 8/6 = 26/6 seconds. On-off cycle ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“When an integer is raised to consecutive powers, the resulting units digits repeat in a CYCLE. 57867¹⁹²⁵⁷⁶: 7¹ --> units digit of 7. 7² --> units digit of 9. (Since the product of the preceding units digit and 7 = 7*7 = 49.) 7³ --> units digit of 3. (Since the product ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“Make a list of two-digit numbers that are 18 less than a perfect square: 36-18 = 18 49-18 = 31 64-18 = 46 81-18 = 63 100-18 = 82 Check whether each option above is equal to 18 less than the square of its digit sum: 18 = (1+8)² - 18 31 = (3+1)² - 18 46 = (4+6)² - 18 63 = (6+3)² - 18 ...”
May 22, 2018
GMATGuruNY posted a reply to NUMBERS in the Problem Solving forum
“To MINIMIZE the number of rooms, we must MAXIMIZE the number of students per room. Let x = the number of students per room. Since each room must have x students -- and we want x to be as large as possible -- x must be equal to the GREATEST COMMON FACTOR of 315, 420, and 1155: 315 = 3*3*5*7 420 ...”
May 22, 2018
GMATGuruNY posted a reply to How many gallons of water must be mixed with 1 gallon in the Problem Solving forum
“Salt percentage in the original solution: 15%. Salt percentage in the added water: 0%. Salt percentage in the mixture: 10%. Let S = the original solution and W = the added water. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: Plot ...”
May 22, 2018
GMATGuruNY posted a reply to How many gallons of water must be mixed with 1 gallon in the Problem Solving forum
“Amount of salt = 15% of 1 gallon = 0.15 gallon. We can PLUG IN THE ANSWERS, which represent the amount of water that must be added to reduce the salt concentration to 10%. B: 2/3 gallon Salt concentration = (amount of salt)/(new total volume) = 0.15/(1 + 2/3) = 0.15/(5/3) = (0.15 * 3)/5 = ...”
May 22, 2018
GMATGuruNY posted a reply to Publishers of travel guides for families typically suffer in the Sentence Correction forum
“B: vacations budgets are low and their efforts to save are intense Here, their seems to refer to vacation budgets -- the nearest preceding plural noun -- implying that the efforts of VACATION BUDGETS are intense. This meaning is nonsensical. Eliminate B. C: more intense efforts Here, it is ...”
May 22, 2018
GMATGuruNY posted a reply to x+y=? in the Data Sufficiency forum
“Statement 1: Case 1: x=0, with the result that y = 3x = 3*0 = 0 In this case, x+y = 0+0 = 0. Case 2: x=1, with the result that y = 3x = 3*1 = 3 In this case, x+y = 1+3 = 4. Since x+y can be different values, INSUFFICIENT. Statement 2: Neither side of the equation can be negative, since the ...”
May 22, 2018
GMATGuruNY posted a reply to If ABCD is square and both AED and CDF are equilateral in the Problem Solving forum
“Because triangles ADE and CDF are equilateral, we get: https://s9.postimg.cc/xtqgckd9n/square_and_equilateral_triangles_1.png Because triangle AED is equilateral, DE = AD. Because ABCD is a square, AD = CD. .Thus, DE=CD, with the result that triangle CDE is isosceles: ...”
May 22, 2018
GMATGuruNY posted a reply to A jar contains 6 red marbles and 9 blue marbles. If Evelyn in the Problem Solving forum
“Case 1: 2 green marbles P(1st marble is green) = 6/15. (Of the 15 marbles, 6 are green.) P(2nd marble is green) = 5/14. (Of the 14 remaining marbles, 5 are green.) To combine these probabilities, we multiply: 6/15 * 5/14 = 1/7. Case 2: 2 red marbles P(1st marble is red) = 9/15. (Of the 15 ...”
May 21, 2018
GMATGuruNY posted a reply to Money invested at x%, compounded annually, triples in value in the Problem Solving forum
“The posted problem has a typo and should read as follows: Since x=8, the approximate number of years for the investment to triple = 112/x = 112/8 = 14. Since the initial investment = 2500, and the amount triples about every 14 years, we get: After the first 14 years --> 3*2500 = 7500. ...”
May 21, 2018
GMATGuruNY posted a reply to In what year was Edward born? in the Data Sufficiency forum
“Test EXTREMES. Case 1: Lisa''s birth month = January 1970 Since Edward was born 14 months earlier, Edward''s birth month = November 1968. Case 2: Lisa''s birth month = December 1970 Since Edward was born 14 months earlier, Edward''s birth month = October 1969. Since Edward''s birth year ...”
May 21, 2018
GMATGuruNY posted a reply to On Monday, Karen had S dollars in her savings account in the Problem Solving forum
“Alternate approach: Let S=30. The answer choices imply the following options for C: A) C=-10 B) C=10 C) C=20 D) C= 90 E) C = 100 From here, we can PLUG IN THE ANSWERS. When the correct answer is plugged in, the two accounts will hold the same amount after the transfer on Wednesday. ...”
May 21, 2018
GMATGuruNY posted a reply to Machine A produces pencils at a constant rate of 9000 in the Problem Solving forum
“To minimize B''s time, we must maximize A''s time. Since each machine can work for at most 8 hours, let A''s time = 8 hours. Since A''s rate = 9000 pencils per hour, the number of pencils produced by A in 8 hours = rt = 9000*8 = 72,000. Remaining pencils = 100,000 - 72,000, = 28,000. Since B''s ...”
May 21, 2018
GMATGuruNY posted a reply to Last year's receipts from the sale of candy on Valentine's in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total sales. Since 385 represents 7% of the total sales, 10% of the correct answer must be a little more than 385. Only D is viable: 10% of 5500 = 550. The correct answer is D.”
May 21, 2018
GMATGuruNY posted a reply to OG 10th Edition Q 74 in the Critical Reasoning forum
“The correct answer must support the conclusion that a well-balanced breakfast is a better vitamin source than is a fortified breakfast cereal.. A: In many foods, the natural combination of vitamins with other nutrients makes those vitamins more usable by the body than are vitamins added in ...”
May 21, 2018
GMATGuruNY posted a reply to A study done on children under the age of twelve showed in the Sentence Correction forum
“The intention here is to convey the following: The study showed THAT X IS TRUE but THAT Y IS TRUE. For the intended meaning to be conveyed clearly, the second that is required. A and B: The study...showed that....but for C: The study showed that...but when These options do not include the ...”
May 21, 2018
GMATGuruNY posted a reply to If 123,456=123a+87 and 234,567=123b+6, how many multiples o in the Problem Solving forum
“For any EVENLY SPACED SET: Count = (biggest - smallest)/increment + 1. The INCREMENT is the difference between successive terms. Smallest multiple of 123 between 123a + 87 and 123b + 6: 123a +123. Biggest multiple of 123 between 123a + 87 and 123b + 6: 123b. Since 123 is the increment ...”
May 21, 2018
GMATGuruNY posted a reply to Jayden draws a regular n-gon. What is the value of n? in the Data Sufficiency forum
“Sum of the interior angles of a quadrilateral = 360, with the result that each angle of a square = 360/4 = 90. For each additional side, the sum of the interior angles increases by 180: Sum of the interior angles of a pentagon = 360+180 = 540, with the result that each angle of a regular pentagon ...”
May 21, 2018
GMATGuruNY posted a reply to statements must be true for all integers a, b and c? in the Problem Solving forum
“a@b = a + b - ab. In other words, a@b = SUM - PRODUCT. Statement I is included in four of the five answer choices. Thus, it is almost certain that statement I must be true. Otherwise, a test-taker will be able to eliminate four answer choices simply by evaluating statement I. To save time, ...”
May 20, 2018
GMATGuruNY posted a reply to A boyis buying two kinds of marbles. One kind costs 25 cents in the Problem Solving forum
“I believe that the following represents the intent of the problem: Cost of 5 pounds of 25-cent marbles = 5*25 = 125 cents. We can PLUG IN THE ANSWERS, which represent the number pounds of 32-cent marbles. When the correct answer is plugged in the average cost per marble ≈ 29. B: 6 ...”
May 19, 2018
GMATGuruNY posted a reply to Two liquids are mixed in the ratio 3:2 and the vendor gains in the Problem Solving forum
“Since the selling price of $11 per liter represents a profit of 10%, the cost per liter = $10. The cost of the first liquid is $2 more than the cost of the second liquid. For the average cost per liter to be $10, the cost of the first liquid must be MORE THAN $10, while the cost of the second ...”
May 19, 2018
GMATGuruNY posted a reply to A farmer who grows strawberries defines . . . in the Data Sufficiency forum
“Statement 1: Since the size of the crop is unknown, we cannot determine how many workers must be hired for the crop to be picked in 15 days. INSUFFICIENT. Statement 2: For 13,500 liters to be picked in 15 days, the amount that must be picked each day = 13,500/15 = 900 liters. Since the rate ...”
May 19, 2018
GMATGuruNY posted a reply to Employment costs rose - GMATPrep in the Sentence Correction forum
“In B, it (singular) does not agree with costs (plural). Eliminate B. C: Employment costs rose...less than they were Here, an ACTION (rose) is illogically compared to a STATE-OF-BEING (were). Eliminate C. lower is an ADJECTIVE. It must serve to modify a NOUN. D and E: Employment costs ...”
May 19, 2018
GMATGuruNY posted a reply to OG 16 Question 27 in the Sentence Correction forum
“One reason to eliminate B: Generally, a COMMA + VERBing modifier must serve to express an action that is concurrent with the nearest preceding action. B implies the following: The Etruscan alphabet in turn had been adapted, adapting itself earlier. Here, the COMMA + VERBing action in red is ...”
May 18, 2018
GMATGuruNY posted a reply to Each of 60 mineral water bottles in a certain shipment is in the Problem Solving forum
“The addition of the word in red clarifies the intent of the problem: Curren total volume = (number of bottles)(average volume per bottle) = 60*800 = 48,000 ml. We can PLUG IN THE ANSWERS, which represent the number of 1000-ml bottles that must be removed to reduce the average volume per ...”
May 18, 2018
GMATGuruNY posted a reply to On May 1 of last year, Jasmin invested x dollars . . . . in the Data Sufficiency forum
“Statement 1: Since we know the interest rate (6% per year, compounded monthly) and the amount of interest earned after one month ($200), we can calculate the amount Jasmin must have invested. SUFFICIENT. Statement 2: Since we know the interest rate (6% per year, compounded monthly) and the ...”
May 18, 2018
GMATGuruNY posted a reply to The Number of students learning Three subjects are as in the Problem Solving forum
“https://s9.postimg.cc/nom8j2aej/math_english_science.png The values in blue represent the number of students studying exactly 1 subject. Sum of the values in blue: 125 - 2(a+b+c). To MINIMIZE the value of this expression, we must MAXIMIZE the value of a+b+c. Since the expression must be ...”
May 18, 2018
GMATGuruNY posted a reply to A shop sells two variants of chocolates - one that costs in the Problem Solving forum
“Rule: MULTIPLE OF X + MULTIPLE OF X = MULTIPLE OF X. MULTIPLE OF X + NON-MULTIPLE OF X = NON-MULTIPLE OF X, Since the price of each chocolate is either $3 or $5, and the total amount sold = $108, we get: 3x + 5y = 108. Since 108 is an integer whose digits sum to a multiple of 3, 108 is a ...”
May 18, 2018
GMATGuruNY posted a reply to The number of coins that Lana and Brad had were in the in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represent the difference between Lana and Brad after the 8-coin gift. When the correct answer is plugged in, the ratio for Lana and Brad before the 8-coin gift = 5/2. D: 14 After the 8-coin exchange: The parts of the resulting ratio for ...”
May 17, 2018
GMATGuruNY posted a reply to Right now, a barrel of water is exactly 40% full of water. in the Data Sufficiency forum
“Since every value in the problem is either a fraction or a percentage -- and no actual volumes are given -- the capacity of the barrel can be any value. Thus, the two statements combines are INSUFFICIENT. The correct answer is E. The phrase in red is ambiguous and would not appear in an ...”
May 17, 2018
GMATGuruNY posted a reply to Is n an integer? in the Data Sufficiency forum
“Both statements are satisfied by the following cases: Case 1: n = 1, with the result that 2n = 2 and 1/n = 1 In this case, n is an integer, so the answer to the question stem is YES. Case 2: n = 1/2, with the result that 2n = 1 and 1/n = 2 In this case, n is NOT an integer, so the answer to the ...”
May 17, 2018
GMATGuruNY posted a reply to How many 4-digit numbers have only even digits? in the Problem Solving forum
“Number of options for the thousands digit = 4. (2, 4, 6, or 8) Number of options for the hundreds digit = 5. (0, 2, 4, 6, or 8) Number of options for the tens digit = 5. (0, 2, 4, 6, or 8) Number of options for the units digit = 5. (0, 2, 4, 6, or 8) To combine these options, we multiply: ...”
May 17, 2018
GMATGuruNY posted a reply to If xy < 4, is x < 2? in the Data Sufficiency forum
“Statement 1: Case 1: y=2 and x=1, with the result that xy < 4 In this case, x<2, so the answer to the question stem is YES. Case 2: y=3/2 and x=2, with the result that xy < 4 In this case, x=2, so the answer to the question stem is NO. Since the answer is YES in Case 1 but NO in Case ...”
May 16, 2018
GMATGuruNY posted a reply to What is the product of all the possible values of x if in the Problem Solving forum
“x²(x+2) + 7x(x+2) + 6(x+2) = 0. Factor out x+2: (x+2)(x² + 7x + 6) = 0 Factor the quadratic in red: (x+2)(x+6)(x+1) = 0 Option for x: x=-2, x=-6, x==-1. Thus, the product of all the solutions = (-2)(-6)(-1) = -12. The correct answer is B.”
May 16, 2018
GMATGuruNY posted a reply to There are 8 books in a shelf that consists of 2 paperback in the Problem Solving forum
“Combinations with at least 1 paperback = (all possible combinations) - (combinations with no paperbacks). All possible combinations: From the 8 books, the number of ways to choose 4 = 8C4 = (8*7*6*5)/(4*3*2*1) = 70. Combinations with no paperbacks: From the 6 hardback books, the number ...”
May 15, 2018
GMATGuruNY posted a reply to Although the bite of brown recluse spiders are rarely fatal in the Sentence Correction forum
“A and B: Although the bite...are rarely fatal Here, are (plural) does not agree with the bite (singular). Eliminate A and B. C: the bite...posing the greatest danger to the infant and elderly, who are particularly vulnerable to their poison Here, their (plural) does not agree with the bite ...”
May 15, 2018
GMATGuruNY posted a reply to In a certain theater, the first row has 12 seats, and each r in the Problem Solving forum
“Since each row has 1 more seat than the preceding row, the row tallies form a set of consecutive integers: 12, 13, 14...48, 49. 50. For any set of consecutive integers: Count = biggest - smallest + 1 Average = (biggest + smallest)/2 Sum = (count)(average). In the problem at hand: Smallest ...”
May 15, 2018
GMATGuruNY posted a reply to How many solutions are possible for the inequality | x - 1 | in the Problem Solving forum
“|a-b| = the DISTANCE between a and b. Thus: |x-1| = the distance between x and 1. |x-6| = the distance between x and 6. Question stem rephrased: For how many values of x is the sum of the two distances less than 2? The distance between 1 and 6 is 5. Thus, if x is BETWEEN the ...”
May 15, 2018
GMATGuruNY posted a reply to Trains A and B travel at the same constant rate in opposite in the Data Sufficiency forum
“Statement 1: Whereas A travels for 2 hours, B begins its journey 1 hour later and travels for 1 hour. A ----------2 hours----------> meeting spot <-----1 hour----- B Since A travels at r miles per hour for 2 hours to meet B, and B travels at r miles per hour for 1 hour to meet A, it takes a ...”
May 14, 2018
GMATGuruNY posted a reply to If x is a positive integer, what is the least common in the Data Sufficiency forum
“Statement 1: x must be a factor of 30 such that the smallest value divisible by both x and 6 is 30. Options for x: x=5, 10, 15, 30. In every case, the LCM for x , 6, and 9 is 90. SUFFICIENT. Statement 2: x must be a factor of 45 such that the smallest value divisible by both x and 9 is 45. ...”
May 14, 2018
GMATGuruNY posted a reply to If y is positive, what is the value of x? in the Data Sufficiency forum
“Since y is positive, |y| = y. Statement 1: x - y = -x - |y| x - y = -x - y x = -x 2x = 0 x = 0. SUFFICIENT. Statement 2: x = y-3 If y=1, then x = 1-3 = -2. If y=2, then x = 2-3 = -1. Since x can be different values, INSUFFICIENT. The correct answer is A.”
May 14, 2018
GMATGuruNY posted a reply to If a = 4b, what percent of 2a is 2b? in the Problem Solving forum
“= Let b=1, implying that a = 4b = 4*1 = 4. What percent of 2a is 2b? 2b/2a = b/a = 1/4 = 25%. The correct answer is C.”
May 14, 2018
GMATGuruNY posted a reply to John bought a shirt, a pair of pants, and a pair of shoes in the Problem Solving forum
“(pant cost)/(total cost) = 20/(10+20+30) = 20/60 = 1/3 = 33⅓%. The correct answer is D.”
May 14, 2018
GMATGuruNY posted a reply to Is |a| + |b| > |a + b| ? in the Data Sufficiency forum
“Is |a| + |b| > |a + b|? Because an absolute value cannot be negative, both sides of the inequality above are NONNEGATIVE, allowing us to SQUARE the inequality (|a| + |b|)² > (|a + b|)² a² + 2|a||b| + b² > a² + 2ab + b² 2|a||b| > 2ab |a||b| > ab. The resulting inequality ...”
May 14, 2018
GMATGuruNY posted a reply to Verbal Review 18 : Kudzu, an Asian vine in the Sentence Correction forum
“Generally, the usage of a passive verb implies one or both of the following: 1. The agent of the passive action is unknown. 2. The agent of the passive action is unimportant to the meaning of the sentence. The SC above is concerned primarily with the rampant GROWTH of Kudzu. To understand this ...”
May 13, 2018
GMATGuruNY posted a reply to Verbal Review 18 : Kudzu, an Asian vine in the Sentence Correction forum
“New genetic evidence provides compelling support for classifying Africa’s forest elephants and its savanna elephants as separate species. Here, for classifying is an adjective serving to describe support. Question: What KIND of support? Answer: support FOR CLASSIFYING.”
May 13, 2018
GMATGuruNY posted a reply to Sentence Correction Question in the Sentence Correction forum
“The SC above appears in GMATPrep. The OA is not C but D.”
May 12, 2018
GMATGuruNY posted a reply to A, B, C, D and E are 5 consecutive points on a straight in the Problem Solving forum
“AB = 5: https://s7.postimg.cc/qie6ijplj/ABCDE_1.png AC = 11: https://s7.postimg.cc/de8m615bb/ABCDE_2.png BC = 2CD: https://s7.postimg.cc/pu5bzcj3b/ABCDE_3.png DE = 4: https://s7.postimg.cc/fk2x04gd3/ABCDE_final.png Thus, AE = 5 + 6 + 3 + 4 = 18. The correct answer is D.”
May 12, 2018
GMATGuruNY posted a reply to The line represented by the equation y=4-2x is the in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the coordinates of point P. The slopes of perpendicular lines are NEGATIVE RECIPROCALS. Since y = -2x + 4 has a slope of -2, perpendicular line segment RP must have a slope of 1/2. Implication: When the correct answer is combined with the coordinates ...”
May 12, 2018
GMATGuruNY posted a reply to An escalator moves downward from street level to a subway in the Problem Solving forum
“DOWNWARD: When the escalator is turned OFF, the number of steps taken by Wesley to travel downward = 70. When the escalator is turned ON, the number of steps taken by Wesley to travel downward = 36, implying that the number of downward steps attributed to the escalator = 70-36 = 34. Implication: ...”
May 11, 2018
GMATGuruNY posted a reply to Twice the birds as last year will migrate to the in the Sentence Correction forum
“A: twice the birds as last year Here, BIRDS are illogically compared to LAST YEAR. Eliminate A. B: double the number...as last year Here, THE NUMBER is illogically compared to LAST YEAR. Eliminate B. C and E: that of last year''s Here that OF and last year''s both serve to convey ...”
May 11, 2018
GMATGuruNY posted a reply to Sentence Correction Question in the Sentence Correction forum
“A, B and C: three times AS many...charge under $8000 a year THAN In these options, than is unidiomatic. Correct: as many X AS Y. Eliminate A, B and C. Only PARALLEL FORMS may be compared. E: three times as many...CHARGE under $8000...as those CHARGING over $16,000. Here, charge is a VERB, ...”
May 11, 2018
GMATGuruNY posted a reply to If the terms of a sequence {An} are defined by An=n/100, whe in the Problem Solving forum
“For any EVENLY SPACED SET: Count = (biggest - smallest)/(increment) + 1. Average = (biggest + smallest)/2. Sum = (count)(average). The INCREMENT is the difference between successive values. Integers between 101 and 200, inclusive: Here, the integers are CONSECUTIVE, so the increment = ...”
May 11, 2018
GMATGuruNY posted a reply to The sum S of the arithmetic sequence a, a+d, a+2d,..., a+(n- in the Problem Solving forum
“For any EVENLY SPACED SET: Count = (biggest - smallest)/(increment) + 1. Average = (biggest + smallest)/2. Sum = (count)(average). The INCREMENT is the difference between successive values. Integers between 1 and 100, inclusive: Here, the integers are CONSECUTIVE, so the increment = 1. ...”
May 11, 2018
GMATGuruNY posted a reply to (2^5+2^6+2^7+2^8)^2=? in the Problem Solving forum
“(2⁵ + 2⁶ + 2⁷ + 2⁸)² = E.”
May 10, 2018
GMATGuruNY posted a reply to The probability of shooting a target increases after a in the Problem Solving forum
“Test an EASY CASE. Let: S = the original probability of shooting the target NS = the original probability of NOT shooting the target New S = the new probability of shooting the target New NS = the new probability of NOT shooting the target Case 1: Let NEW NS = 0.1, implying that the NEW S = ...”
May 10, 2018
GMATGuruNY posted a reply to abc0 is a positive, four-digit integer, where a, b and c are in the Data Sufficiency forum
“An integer is divisible by 4 only if its last two digits form a multiple of 4. For example: 93724 is divisible by 4 because its last two digits -- 2 and 4 -- form 24, which is a multiple of 4. Question stem, rephrased: Is the integer c0 a multiple of 4? Statement 1: No information about c. ...”
May 10, 2018
GMATGuruNY posted a reply to The original price of a certain Television set is discounted in the Problem Solving forum
“Let P = 100 and x = 10, implying that 2x = 20. Price after an x% discount = 100 - (10% of 100) = 100 - 10 = 90. Price after a 2x% discount = 90 - (20% of 90) = 90 - 18 = 72. The correct answer must yield a resulting price of $72 when x=10. Only B works: 100(1 - 0.03*10 + 0.0002*10²) = 100(1 ...”
May 10, 2018
GMATGuruNY posted a reply to Three friends rented a car for a week and divided the cost e in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total cost. When the correct answer is plugged in, increasing the number of friends from 3 to 4 will reduce the cost per person by $15. Since the total cost is divided equally among 3 or 4 friends, the correct answer is almost certainly a multiple ...”
May 10, 2018
GMATGuruNY posted a reply to OG Two works published in 1984 in the Reading Comprehension forum
“golden age = a period when something was the most successful. From the passage: Women also gained power in comparison with their previous status, owning a higher proportion of real estate, for example. In contrast, Buel and Buel’s biography provides ample raw material for questioning the myth, ...”
May 9, 2018
GMATGuruNY posted a reply to Data Sufficiency Problem in the Data Sufficiency forum
“Since the average price = 141, one price must be LESS than 141, while the other price must be GREATER than 141. Statement 1: Model P sold for $30 less than Model Q. Thus, p< 141, while q>141. Check the ONLY case that also satisfies statement 2: Case 1: p=120 and q=150. To evaluate ...”
May 9, 2018
GMATGuruNY posted a reply to x and y are positive integers. If p and q are diff in the Data Sufficiency forum
“To determine the number of positive factors of an integer: 1) Prime-factorize the integer 2) Add 1 to each exponent 3) Multiply For example: 72 = 2³ * 3². Adding 1 to each exponent and multiplying, we get (3+1)*(2+1) = 12 factors. Here''s why: To determine how many factors ...”
May 9, 2018
GMATGuruNY posted a reply to If snow accumulation increased at a constant rate of 30 mill in the Problem Solving forum
“(1 millimeter accumulation) * (1 hour)/(30 millimeters accumulation) * (3600 seconds)/(1 hour) = 3600/30 = 120 seconds. In the equation above, all of the colored measurments CANCEL OUT, leaving the answer in terms of seconds. The correct answer is E.”
May 9, 2018
GMATGuruNY posted a reply to When a=x+(1/x) and b=x-(1/x), what is a^2 – b^2? in the Problem Solving forum
“Let x=1, with the following results: a = 1 + (1/1) = 2. b = 1 - (1/1) = 0. a² - b² = 2² - 0² = 4. When x=1, the correct answer must yield a value of 4. Only E is viable. The correct answer is E.”
May 9, 2018
GMATGuruNY posted a reply to Mr. and Mrs. Wiley have a child every J years. Their oldest in the Problem Solving forum
“Let J=2. Let 2000 = year in which the first child is born. Let now = 2006. Since a child is born every 2 years, there are now 4 children -- born in 2000, 2002, 2004 and 2006 -- and the oldest age is T=6. When a child is born 2 years from now, the number of children = 5. This is our target. ...”
May 9, 2018
GMATGuruNY posted a reply to Modifier in the Sentence Correction forum
“I share your concern about the OA. Please revisit my previous post, which has been revised to express the reasons for my concern.”
May 8, 2018
GMATGuruNY posted a reply to Which of the following is equal to 2^{k-1}3^{k+1}? in the Problem Solving forum
“Let k=1: $${2^{k-1}3^{k+1}} = {2^{1-1}3^{1+1}} = {2^{0}3^{2}} = 1*9 = 9.$$ Now plug k=1 into the answers to see which yields a value of 9. Only B works: 3²6^(k-1) = 9*6⁰ = 9*1 = 9. The correct answer is B.”
May 8, 2018
GMATGuruNY posted a reply to At the end of each year, the value of a certain antique watc in the Problem Solving forum
“Let k=1 and c=200%, implying that the value of the $1 watch increases by 200% each year. Value in 1993 = 1 + (200/100)(1) = 3. m = value in 1994 = 3 + (200/100)(3) = 9. Value in 1995 = 9 + (200/100)(9) = 27. This is our target. Now plug k=1 and m=9 into the answers to see which yields our ...”
May 8, 2018
GMATGuruNY posted a reply to A finite sequence {An} is arithmetic. If each term An of the in the Data Sufficiency forum
“An arithmetic sequence is an EVENLY SPACED SET. In an evenly spaced set, AVERAGE = MEDIAN. Question stem, rephrased: Is the median of the set even? Statement 1: Case 1: {0, 2} In this case, the median of the set is 1, so the answer to the rephrased question stem is NO. Case 2: {0, 2, 4} In ...”
May 7, 2018
GMATGuruNY posted a reply to If 5m=25^{2n}, what is the value of m, in terms of n? in the Problem Solving forum
“Let n = 1/2. Substituting n = 1/2 into 5m = 25^(2n), we get: 5m = 25¹ m = 5. The question stem asks for the value of m (5). Now plug n = 1/2 into the answers to see which yields the target value of 5. Only C works: m = 5^(4n-1) = 5¹ = 5. The correct answer is C.”
May 7, 2018
GMATGuruNY posted a reply to If a car went the first third of the distance at 80 kmh in the Problem Solving forum
“Let each third of the distance = 240 km, implying that the total distance = 3*240 = 720 km. Since the rate for the first third = 80 kmh, the time to travel the first third = d/r = 240/80 = 3 hours. Since the rate for the second third = 24 kmh, the time to travel the second third = d/r = 240/24 = ...”
May 6, 2018
GMATGuruNY posted a reply to W, X, Y and Z each represent a different number 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.”
May 6, 2018
GMATGuruNY posted a reply to Modifier in the Sentence Correction forum
“A conjunction such as and must serve to connect PARALLEL FORMS. A and D: forms...and lowering In these options, forms (verb) and lowering (modifier) are not parallel forms. Eliminate A and D. C: forming...and lowers Here, forming (modifier) and lowers (verb) are not parallel forms. Eliminate ...”
May 6, 2018
GMATGuruNY posted a reply to Is x greater than zero? in the Data Sufficiency forum
“Each statement implies that x is NONZERO, with the result that any EVEN POWER of x will yield a POSITIVE value. Thus, we can simplify the inequalities by dividing each side by x². Statement 1: x⁶ > x² x⁶/x² > x²/x² x⁴ > 1. The resulting inequality requires that x>1 or ...”
May 6, 2018
GMATGuruNY posted a reply to Jacob drove from Town A to Town B at an average rate of in the Problem Solving forum
“Let the distance = 12 miles. Let x = 2 miles per hour, y = 3 miles per hour, and z = 6 miles per hour. Total time for the 3 trips = 12/2 + 12/3 + 12/6 = 12 hours. Average rate for the 3 trips = (total distance)/(total time) = (12+12+12)/12 = 3 miles per hour. This is our target. Now we ...”
May 6, 2018
GMATGuruNY posted a reply to The remainder, when a number n is divided by 6, is p. in the Data Sufficiency forum
“Statement 1: Case 1: n=8 Since n/6 = 8/6 = 1 R2, p=2. Since n/12 = 8/12 = 0 R8, q=8. In this case, p<q, with the result that the answer to the question stem is YES. Case 2: n=16 Since n/6 = 16/6 = 2 R4, p=4. Since n/12 = 16/12 = 1 R4, q=4. In this case, p=q, with the result that the ...”
May 6, 2018
GMATGuruNY posted a reply to A rectangular box is 10 inches wide, 10 inches long 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 + 5² d² = 225 d = 15. The correct answer is ...”
May 6, 2018
GMATGuruNY posted a reply to If n is an integer between 10 and 99, is n < 80? in the Data Sufficiency forum
“Statement 1: Case 1: n = 11, with the result that the sum of the two digits of n = 1+1 = 2 In this case, n < 80, so the answer to the question stem is YES. Case 2: n = 83, with the result that the sum of the two digits of n = 8+3 = 11 In this case, n > 80, so the answer to the question ...”
May 6, 2018
GMATGuruNY posted a reply to In an experiment, two different types of recorded in the Critical Reasoning forum
“Experiment: In nursery A, classical music was played; in nursery B, rock music was played. Result: The babies in nursery A cried less, suffered fewer minor ailments, and gained more weight than did the babies in nursery B. Implied conclusion: The babies in nursery A had better outcomes ...”
May 5, 2018
GMATGuruNY posted a reply to In a room filled with 7 people, 4 people phave exactly 1 in the Problem Solving forum
“Let''s say that the 7 people are ABCDEFG. 4 people have exactly 1 sibling: Let''s say that A and B are siblings and that C and D are siblings. This means: A has 1 sibling (B). B has 1 sibling (A). C has 1 sibling (D). D has 1 sibling (C). 3 people have exactly 2 siblings: Let''s say ...”
May 5, 2018
GMATGuruNY posted a reply to If x is the sum of the first 10 positive multiples of 3 and in the Problem Solving forum
“For any EVENLY SPACED SET: AVERAGE = (BIGGEST + SMALLEST)/2. SUM = (COUNT)(AVERAGE). The first 10 positive multiples of 3 are as follows: 3, 6, 9, 12, 15, 18, 21, 24, 27, 30. Thus: Average = (biggest + smallest)/2 = (30+3)/2 = 16.5. x = sum = (count)(average) = 10*16.5 = 165. The first ...”
May 4, 2018
GMATGuruNY posted a reply to What is the largest integer if the sum of three consecutive in the Problem Solving forum
“Consecutive even integers constitute an EVENLY SPACED SET. For any evenly spaced set, MEDIAN = AVERAGE. In the problem at hand: Median = Average = 318/3 = 106. Since the median of the 3 consecutive even integers = 106, the greatest of the 3 consecutive even integers = 108. The correct answer ...”
May 4, 2018
GMATGuruNY posted a reply to Harold works at a resort from the beginning of March to the in the Problem Solving forum
“Excluding August, let the average earned each month = $1, implying that the total earned for the 6 non-August months = 6*1 = $6. Since 3 times the average is earned in August, the amount earned in August = 3*1 = $3, bringing the total earnings to $9. Resulting fraction: August/Total = 3/9 = 1/3. ...”
May 3, 2018
GMATGuruNY posted a reply to If x and y are two different integers, is |x|=|y|? in the Data Sufficiency forum
“Case 1: y=0, with the result that x = y+2 = 0+2 = 2 In this case, |x|=2 and |y|=0, so the answer to the question stem is NO. Case 2: y=-1, with the result that x = y+2 = -1+2 = 1 In this case, |x|=1 and |y|=1, so the answer to the question stem is YES. Since the answer is NO in Case 1 but YES in ...”
May 3, 2018
GMATGuruNY posted a reply to A group of 8 friends want to play doubles tennis. in the Problem Solving forum
“Since there are 8 people, the first friend selected can be paired with 7 different people, yielding 7 possible pairs. Since 6 people remain, the next friend selected can be paired with 5 different people, yielding 5 possible pairs. Since 4 people remain, the next friend selected can be paired ...”
May 3, 2018
GMATGuruNY posted a reply to There are three blue marbles, three red marbles, and three in the Problem Solving forum
“P(good outcome) = P(one way) * total possible ways. Let B = blue and R = red. P(one way): One way to select exactly 1 blue marble and 2 red marbles is BRR. P(B on the 1st pick) = 3/9. (Of the 9 marbles, 3 are blue.) P(R on the 2nd pick) = 3/8. (Of the 8 remaining marbles, 3 are red.) P(R ...”
May 3, 2018
GMATGuruNY posted a reply to How many odd three-digit integers greater than 800 are there in the Problem Solving forum
“Case 1: Hundreds digit = 8 Number of options for the units digit = 5. (Any of the 5 odd digits.) Number of options for the tens digit = 8. (Of the 10 digits, any but the two already used.) To combine the options above, we multiply: 5*8 = 40. Case 1: Hundreds digit = 9 Number of options for ...”
May 3, 2018
GMATGuruNY posted a reply to If x is a positive integer, is x/30 a terminating decimal? in the Data Sufficiency forum
“A TERMINATING decimal has a FINITE NUMBER OF DIGITS: .5 .123 .8730253. A NON-TERMINATING decimal has an INFINITE NUMBER OF DIGITS: .33333.... .121212.... .871871871... To determine whether a fraction will yield a terminating decimal: 1. Put the fraction in its MOST REDUCED FORM. 2. ...”
May 3, 2018
GMATGuruNY posted a reply to How many multiples of 4 lie between 4^4 and 4^5, inclusive? in the Problem Solving forum
“The positive multiples of 4 constitute an EVENLY SPACED SET. For any evenly spaced set: Number of values = (biggest - smallest)/increment + 1. The INCREMENT is the distance between one term and the next. The positive multiple of 4 have an increment of 4. Thus: Number of multiples of 4 ...”
May 3, 2018
GMATGuruNY posted a reply to The distance between Alice’s house and Bob's is 120 miles. in the Problem Solving forum
“Total distance between Alice and Bob =120 miles. Since Alice travels 40 miles from her home to meet Bob, Bob travels the remaining 80 miles. Since Bob travels twice as far as Alice, his rate is twice Alice''s rate. Since Alice''s rate = x miles per hour, Bob''s rate = 2x miles per hour. The ...”
May 2, 2018
GMATGuruNY posted a reply to Jane and Ashley take 20 days and 40 days respectively to in the Problem Solving forum
“Let the job = the LCM of 20 and 40 = 40 units. Since Jane takes 20 days to produce the 40-unit job, Jane''s rate = w/r = 40/20 = 2 units per day. Since Ashley takes 40 days to produce the 40-unit job, Jane''s rate = w/r = 40/40 = 1 unit per day. During Jane''s 8-day break, Ashely works alone ...”
May 1, 2018
GMATGuruNY posted a reply to John and Amanda stand at opposite ends of a straight road in the Problem Solving forum
“All possible outcomes: Number of possible rates for John = 4. Number of possible rates for Amanda = 4. To combine the number of rate options for John with the number of rate options for Amanda, we multiply: 4*4 = 16. Good outcomes: John will travel farther than Amanda if his rate is greater ...”
April 30, 2018
GMATGuruNY posted a reply to On the number line, 0 lies between x and y. Is x>y? in the Data Sufficiency forum
“Since 0 lies between x and y, x and y have DIFFERENT SIGNS. Statement 1: The distance between x and 0 is 2 times the distance between y and 0 Thus: |x| = 2|y| Case 1: y=1, implying that |x| = 2 Since x have must have different sign from y, x=-2. In this case, x < y, so the answer to the ...”
April 30, 2018
GMATGuruNY posted a reply to If p and q are positive integers such in the Data Sufficiency forum
“pq will have 4 distinct positive factors in the following cases: Case 1: pq = a³, where a is a prime number. Case 2: pq = ab, where a and b are distinct prime numbers. Examples of Case 1: pq = 2³ = 8, with the result that pq has factors 1, 2, 4 and 8. pq = 3³ = 27, with the result that pq ...”
April 30, 2018
GMATGuruNY posted a reply to If the profit on a product is 20 percent of its sales price, in the Problem Solving forum
“Let the sale price = 100, implying that the profit = 0.2(100) = 20 and that the cost price = (sale price) - (profit) = 100-20 = 80. What percent of the cost price is the profit? profit/cost = 20/80 = 1/4 = 25%. The correct answer is B.”
April 30, 2018
GMATGuruNY posted a reply to Double matrix method in the Data Sufficiency forum
“To organize the data, use the following DOUBLE-MATRIX: https://s31.postimg.cc/yinkrxs7b/matrix_tennis_and_swimming_statement_0.png To answer the question stem, we need to determine the values in the two boxes with question marks (tennis but not swimming, swimming but not tennis). Statement ...”
April 30, 2018
GMATGuruNY posted a reply to A lighting store is stocked with 410 fixtures. Some of the in the Problem Solving forum
“The expression in blue represents the total number of imported lamps. Since x/4 is being SUBTRACTED, the expression will be minimized if x/4 is AS GREAT AS POSSIBLE. Since x must be less than or equal to the total number of fixtures -- 410 -- the greatest possible integer value for x/4 will be ...”
April 28, 2018
GMATGuruNY posted a reply to A lighting store is stocked with 410 fixtures. Some of the in the Problem Solving forum
“5% of the floor lamps are imported. 5% = 5/100 = 1/20. Since 1/20 of the floor lamps are imported, the total number of floor lamps must be a MULTIPLE OF 20. 30% of the table lamps are imported. 30% = 30/100 = 3/10. Since 3/10 of the table lamps are imported, the total number of table lamps ...”
April 28, 2018
GMATGuruNY posted a reply to Given that N=a3b4c5 where a, b and c are distinct prime in the Problem Solving forum
“The problem should read as follows: The exponent for a perfect square must be a MULTIPLE OF 2. The exponent for a perfect cube must be a MULTIPLE OF 3. The exponent for a perfect fifth must be a MULTIPLE OF 5. Thus, the exponent for an integer that is a perfect square, a perfect cube and a ...”
April 28, 2018
GMATGuruNY posted a reply to Is xy< 10? in the Data Sufficiency forum
“Statements combined: If x=0 and y=0, then xy = 0, so the answer to the question stem is YES. If x=-10 and y=-10, then xy = 100, so the answer to the question stem is NO. Since the answer is YES in the first case but NO in the second case, the two statements combined are INSUFFICIENT. The ...”
April 28, 2018
GMATGuruNY posted a reply to Is p^2 - 1 divisible by 12? in the Data Sufficiency forum
“Question stem, rephrased: Is (p+1)(p-1) divisible by 12? Statement 1: Case 1: p=4 In this case, (p+1)(p-1) = 5*3 = 15, so the answer to the question stem is NO. Case 2: p=5 In this case, (p+1)(p-1) = 6*4 = 24, so the answer to the question stem is YES. Since the answer is NO in Case 1 but ...”
April 28, 2018
GMATGuruNY posted a reply to If −2 < x ≤ 1/2 and 7< y ≤ 10...... in the Problem Solving forum
“Since y is POSITIVE and x² must be NONNEGATIVE, only two cases are possible: Case 1: yx² = (positive)(0) = 0. Case 2: yx² = (positive)(positive) = positive. Case 1 is possible if y=8 and x=0. Thus, the least possible value for yx² is 0. The correct answer is C.”
April 28, 2018
GMATGuruNY posted a reply to If x + z = 8, 2y + z =11, and 3x + y= 19, what is the in the Problem Solving forum
“One approach: Subtracting x+z = 8 from 2y+z = 11, we get: (2y+z) - (x+z) = 11-8 2y - x = 3 2y - 3 = x. Substituting x = 2y-3 into 3x+y = 19, we get: 3(2y-3) + y = 19 6y - 9 + y = 19 7y = 28 y = 4. Substituting y=4 into 2y + z = 11, we get: (2*4) + z = 11 z = 3. Substituting z=3 ...”
April 28, 2018
GMATGuruNY posted a reply to If x y and z are positive is xz = 7xy? in the Data Sufficiency forum
“Since x is positive, we can divide both sides of the question stem by x: xz/x = 7xy/x z =7y. Questions stem, rephrased: Does z = 7y? Statement 1: z/y = 7 z = 7y. Thus, the answer to the question stem is YES. Statement 2: No information about z. INSUFFICIENT. The correct answer is ...”
April 28, 2018
GMATGuruNY posted a reply to If n = (33)^43 + (43)^33 what is the units digit of n? in the Problem Solving forum
“3¹ --> units digit of 3. 3² --> units digit of 9. (Since the product of the preceding units digit and 3 = 3*3 = 9.) 3³ --> units digit of 7. (Since the product of the preceding units digit and 3 = 9*3 = 27.) 3⁴ --> units digit of 1. (Since the product of the preceding units ...”
April 28, 2018
GMATGuruNY posted a reply to Z is 120% of Y. X is smaller than Z by 80%. What percentage in the Problem Solving forum
“Since Z is 120% of Y, we get: Z/Y = 120/100 = 6/5. X is 80% less than Z implies that X is 20% of Z: X/Z = 20/100 = 1/5. What percentage of Y is X? X/Y = X/Z * Z/Y = 1/5 * 6/5 = 6/25 = 24/100. Thus: X is 24% of Y. The correct answer is E.”
April 27, 2018
GMATGuruNY posted a reply to NOT true in the Problem Solving forum
“If -14 < a-b < 8 (option B) is multiplied by -1, we get: 14 > -a+b > -8 14 > b-a > -8 -8 < b-a < 14. Implication: If B is true, then C is NOT true, since C indicates that -7 < b-a < 14. In other words: B and C cannot both be true. Test whether B or C is true. ...”
April 27, 2018
GMATGuruNY posted a reply to Lightbox, Inc., owns almost all of the movie theaters in in the Critical Reasoning forum
“Premises: Attendance at Lightbox''s theaters is only just large enough for profitability now, and the county''s population is not expected to increase over the next ten years. Conclusion: The plan to double the number of screens will not prove profitable. To weaken the conclusion, the correct ...”
April 27, 2018
GMATGuruNY posted a reply to If g is a function defined for all x by g(x)=(x^4)/16 in the Problem Solving forum
“Let x=2, with the result that g(x) = g(2) = 2⁴/16 = 1. The question stem asks for the value of g(2x): g(2x) = g(2*2) = g(4) = 4⁴/16 = (16*16)/16 = 16. Now plug g(x) = 1 into the answers to see which yields the target value of 16 for g(2x). Only E works: 16g(x) = 16*1 = 16. The correct ...”
April 27, 2018
GMATGuruNY posted a reply to If y = 3x, then the value of 10% of y is in the Problem Solving forum
“Let x=10 and y = 3x = 3*10 = 30. The question stem asks for the value of 10% of y: 10% of y = (10/100)(30) = 3. Now plug x=10 into the answers to see which yields the target value of 3. Only B works: 0.3x = 0.3(10) = 3. The correct answer is B. Algebra: Since y = 3x, we get: 10% of y = ...”
April 27, 2018
GMATGuruNY posted a reply to Machine A and machine B process the same work at different in the Problem Solving forum
“Machine D processes work three times as fast as Machine C. Machine D’s work rate is also exactly four times Machine B’s rate. Let D = 12 units per minute, implying that C= 4 units per minute and B = 3 units per minute. Machine C processes work as fast as Machines A and B combined. Since C ...”
April 26, 2018
GMATGuruNY posted a reply to The pesticide Azocide, introduced to central valley farms in the Sentence Correction forum
“because + NO OF must be followed by a CLAUSE. A: because other pesticides...neutralizing its desired effect. Here, the red portion after because lacks a verb and thus does not constitute a clause. Eliminate A. B: The pesticide Azocide has become ineffective...because of the chemical ...”
April 26, 2018
GMATGuruNY posted a reply to Overuse of antibiotics often leads to a reduction in the in the Sentence Correction forum
“B and C: If overused, one theory Here, overused seems to refer to theory, implying that ONE THEORY might be OVERUSED. This meaning is nonsensical. The intended meaning of the original sentence is that ANTIBIOTICS might be overused. Eliminate B and C. D: The observation...has recently given ...”
April 26, 2018
GMATGuruNY posted a reply to The students at a school took a math exam. Is the average (a in the Data Sufficiency forum
“Statement 1: No information about the median. INSUFFICIENT. Statement 2: Let the total number of scores = 100. Since 51 of the 100 scores are greater than the average, the 50th highest score and the 51st highest score are both greater than the average. Thus, the median score -- which is ...”
April 25, 2018
GMATGuruNY posted a reply to A bag contains only black and white balls. What is the proba in the Data Sufficiency forum
“Question stem, rephrased: What fraction of the balls are black? Statement 1: The total number of balls in the bag is 12 No information about what fraction of the balls are black. INSUFFICIENT. Statement 2: The number of white balls is 3 times the number of black balls Of every 4 balls, 3 ...”
April 25, 2018
GMATGuruNY posted a reply to Alice sells apples. She sold at least 10 lb every day last w in the Problem Solving forum
“Since at least 10 apples are sold every day, the least number of apples sold on a single day = 10. The maximize the range, we must maximize the GREATEST number of apples sold on a single day. To maximize the greatest number of apples sold on a single day, we must MINIMIZE the number of apples sold ...”
April 25, 2018
GMATGuruNY posted a reply to It takes Kaya a total of 9 hours to go from home to work in the Problem Solving forum
“Time and rate have a RECIPROCAL RELATIONSHIP: If John''s time is twice Mary''s time, then John''s rate is 1/2 Mary''s rate. Here, the rate for the return trip is twice the rate for the trip to work, implying that the time for the return trip is 1/2 the time for the trip to work. Since the total ...”
April 24, 2018
GMATGuruNY posted a reply to Alice and Bruce each bought a refrigerator, and the sum of in the Problem Solving forum
“Let A = Alice''s amount and B = Bruce''s amount. Twice of what Alice paid was $75 more than what Bruce paid. Since twice Alice''s amount is equal to $75 more than Bruce''s amount, we get: 2A = 75 + B 2A - 75 = B. The sum of their purchases was $900. Thus, the two blue values above must sum ...”
April 24, 2018
GMATGuruNY posted a reply to Set T consists of 82 consecutive odd integers. If the sum of in the Problem Solving forum
“For any set of consecutive integers: SUM = (COUNT)(MEDIAN). In the problem above: SUM = 3⁸ - 165 = (3⁴3⁴) - 165 = (81*81) - 165 = (integer with a units digit of 1) - (integer with a units digit of 5) = integer with a units digit of 6. COUNT = 82 integers. Since the sum has a units ...”
April 24, 2018
GMATGuruNY posted a reply to P persons have decided to rent a van to tour while on in the Problem Solving forum
“Let x = $10 and P = 10 people. Since 10 people plan to split the $10 cost, the expected cost per person = (total cost)/(number of people) = 10/10 = $1. Let D=9, implying that 9 of the 10 people cancel, with the result that the one remaining person must pay the entire $10. Since the one remaining ...”
April 24, 2018
GMATGuruNY posted a reply to OG In the Sonoran Desert of northwestern Mexico in the Reading Comprehension forum
“From the passage: During spring in the Sonoran Desert...diurnal cactus-pollinating birds are significantly more abundant. Compared with the Sonoran Desert''s cardon and saguaro, columnar cacti in southern Mexico produce far fewer flowers per night, with the result that bats are able to pollinate ...”
April 24, 2018
GMATGuruNY posted a reply to OG In the Sonoran Desert of northwestern Mexico in the Reading Comprehension forum
“From the passage: Pollinators can be unreliable for several reasons. They may be dietary specialists, but their abundance may be chronically low relative to the availability of flowers. Nectar-feeding bats...being unreliable cactus-flower pollinators, and daytime pollinators more abundant and ...”
April 24, 2018
GMATGuruNY posted a reply to What is the value of x? \(|x+2|+|x-3| = |2x+3|\) in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of x. E: x=7 Substituting x=7 into |x+2|+|x-3|=|2x+3|, we get: |7+2|+|7-3|=|2*7 + 3| 9 + 4 = 17 13 = 17. Doesn''t work. Eliminate E. D: x=4 Substituting x=4 into |x+2|+|x-3|=|2x+3|, we get: |4+2|+|4-3|=|2*4 + 3| 6 + 1 = 11 7 = ...”
April 23, 2018
GMATGuruNY posted a reply to How many positive integers less than 60 are equal to in the Problem Solving forum
“An even multiple of 5 is divisible by 2 and 5. Any integer divisible by 2 and 5 is a MULTIPLE OF 10. The following multiples of 10 are less than 60: 10, 20, 30, 40, 50. Total options = 5. The correct answer is B.”
April 23, 2018
GMATGuruNY posted a reply to If n is an integer, is n - 1 even? in the Data Sufficiency forum
“If n-1 is even, we get the following options for n-1: n-1 = 0, 2, 4, 6, 8, 10, 12... Adding 1 to every value in the list above, we get the following options for n: n = 1, 3, 5, 7, 9, 11, 13.... The resulting list indicates that n-1 will be even if N IS ODD. Question stem, rephrased: Is n odd? ...”
April 23, 2018
GMATGuruNY posted a reply to If a continuous cable 10m long was marked off at intervals in the Problem Solving forum
“The length of the cable can be ANY VALUE. To make the math easier, let the length of the cable = the product of the two denominators = 4*5 = 20 meters. When the cable is divided into 4ths, markings are yielded at 5, 10, and 15: ...”
April 23, 2018
GMATGuruNY posted a reply to og210 in the Sentence Correction forum
“The blue portion constitutes the core of the sentence. The green portion is a RESTRICTIVE modifier serving to describe a giant fungus. Generally, a restrictive modifier is considered ESSENTIAL: it cannot be omitted without a loss of meaning. If the green portion here were omitted, a reader would ...”
April 22, 2018
GMATGuruNY posted a reply to Evaluate the Argument............OG Diagnostic test in the Critical Reasoning forum
“The statements above are all reasonable.”
April 22, 2018
GMATGuruNY posted a reply to Numbers a and b are positive integers. If a^4-b^4 is divided in the Data Sufficiency forum
“a⁴-b⁴ = (a²+b²)(a²-b²) = (a²+b²)(a+b)(a-b). Statement 1: Since a+b is divisible by 3, (a²+b²)(a+b)(a-b) is divisible by 3. Thus, dividing a⁴-b⁴ by 3 will yield a remainder of 0. SUFFICIENT. Statement 2: In other words, a²+b² is 2 more than a multiple of 3: a²+b² = 3k ...”
April 22, 2018
GMATGuruNY posted a reply to Percentage change in the Problem Solving forum
“The question stem asks for the percent change in the following RATIO: (royalty percentage) : (number of copies).'' Initial ratio = 10 : 10,000. New ratio = 12 : 15,000. From 10/10000 to 12/15000 = a 20% DECREASE. In your solution, you calculate the percent change only for the values in red: ...”
April 21, 2018
GMATGuruNY posted a reply to Five digit combination problem in the Problem Solving forum
“A five-digit integer formed from the five given digit options will be divisible by 2 and/or 5 if its units digit is 0, 2, 4 or 5. Thus: Number of options for the units place = 4. (0, 2, 4, or 5). Number of options for the ten-thousands place = 4. (Any of the 5 digits except 0.) Number of options ...”
April 21, 2018
GMATGuruNY posted a reply to OG In the Sonoran Desert of northwestern Mexico in the Reading Comprehension forum
“Yet the flowers of the Sonoran Desert cacti have EVOLVED to remain open after sunrise, allowing pollination by such diurnal visitors as bees and birds. Why have these cacti expanded their range of pollinators by remaining open and receptive in daylight? The rest of the passage attempts to answer ...”
April 21, 2018
GMATGuruNY posted a reply to Evaluate the Argument............OG Diagnostic test in the Critical Reasoning forum
“This line of reasoning is correct.”
April 21, 2018
GMATGuruNY posted a reply to Percentage change in the Problem Solving forum
“Since the question stem asks for a PERCENT CHANGE, we can make the math easier by using easier values. The percent change will remain constant as long as the first set of copies and the second set of copies are in the following ratio: 10000:15000 = 10:15. Thus, the prompt can be rephrased as ...”
April 21, 2018
GMATGuruNY posted a reply to Is ∣x∣<1 ? in the Data Sufficiency forum
“Statement 1: Since the square of a value must be NONNEGATIVE, y² ≥ 0. If y²=0, then x = 1/3. If y²>0, then x = 1/(more than 3), implying that x < 1/3. Since x≤1/3, the answer to the question stem is YES. SUFFICIENT. Statement 2: No information about x. INSUFFICIENT. The ...”
April 20, 2018
GMATGuruNY posted a reply to Does x = 3? in the Data Sufficiency forum
“Statement 1: (x−3)(y−1) = 0 If y-1=0 -- implying that y=1 -- then x-3 can be equal to ANY VALUE. For example: x=3 and y=1, with the result that (x-3)(y-1) = (3-3)(1-0) = 0*0 = 0. x=4 and y=1, with the result that (x-3)(y-1) = (4-1)(1-0) = 3*0 = 0. Since the answer to the question stem is ...”
April 20, 2018
GMATGuruNY posted a reply to If k is a positive two-digit integer, what is the tens in the Data Sufficiency forum
“Statement 1: Case 1: k=14, with the result that the tens digit of k is 1 Case 2: k=23, with the result that the tens digit of k is 2 Since the tens digit can be different values, INSUFFICIENT. Statement 2: Make a list of option for k+6: k+6 = 30, 31, 32, 33, 34, 35, 36, 37, 38, 39. To yield ...”
April 20, 2018
GMATGuruNY posted a reply to If a > 0 and b > 0, is a/b > b/a ? in the Data Sufficiency forum
“Is a/b > b/a? Since a and b are both positive, we can CROSS-MULTIPLY and take the square root of both sides: a² > b². a > b. Question stem, rephrased: Is a > b? Statement 1: a = b-2 Since a is 2 less than b, the answer to the question stem is NO. SUFFICIENT. Statement 2: ...”
April 20, 2018
GMATGuruNY posted a reply to Is kw>0? in the Data Sufficiency forum
“Statement 1: Case 1: k=10 and w=0 In this case, kw=0, so the answer to the question stem is NO. Case 2: k=11 and w=1 In this case, kw=11, so the answer to the question stem is YES. Since the answer is NO in Case 1 but YES in Case 2, INSUFFICIENT. Statement 2: Case 3: k=0 and w=0 In this ...”
April 20, 2018
GMATGuruNY posted a reply to a percent of b is c and c percent of d is e, then a is what in the Problem Solving forum
“a percent of b is c Let a=b=c=100. since 100% of 100 is 100. c percent of d is e. Let c=d=e=100. since 100% of 100 is 100. a is what percent of e? Since a=e=100, a is 100% of e. The correct answer must yield the value in blue when b=d=100 is plugged in. Only E works: 1000000/bd = ...”
April 20, 2018
GMATGuruNY posted a reply to GMATPrep EP2: One key to predicting a competitor's in the Reading Comprehension forum
“From the passage: The dominant player, as the target of consumer backlash, introduced a variety of foods it promoted as healthy, The other, foreseeing this move, saw an opportunity to find market share in the less health-conscious fast-food segment and so introduced high-fat, high-calorie ...”
April 19, 2018
GMATGuruNY posted a reply to Jim takes a seconds to swim c meters at a constant rate in the Problem Solving forum
“Let c=6 meters, a=2 seconds, and b=1 second. Since Jim takes 2 seconds to travel the 6-meter distance, Jim''s rate = d/t = 6/2 = 3 meters per second. Since Roger takes 1 second to travel the 6-meter distance, Roger''s rate = d/t = 6/1 = 6 meters per second. When Jim and Roger travel toward each ...”
April 19, 2018
GMATGuruNY posted a reply to When a and b are positive integers, what is the greates in the Data Sufficiency forum
“Consecutive integers are COPRIMES: they share no factors other than 1. Statement 1: a=100, implying that a+100 = 100+100 = 200 Case 1: b=100, with the result that a+b = 100+100 = 200 The GCF for the value in blue (200) and Case 1 (200) is 200. Case 2: b=101, with the result that a+b = 100+101 ...”
April 19, 2018
GMATGuruNY posted a reply to What was the percent increase in the value of a certain in the Data Sufficiency forum
“If a value DOUBLES, then it increases by 100%: x + (100% of x) = x + x = 2x. Thus, Statement 2 indicates that the percent increase = 100. SUFFICIENT.”
April 18, 2018
GMATGuruNY posted a reply to A certain office supply store stocks 2 sizes of in the Problem Solving forum
“Case 1: The notepads are all of the same size and the same color Number of size options = 2. Number of color options = 4. To combine the options above, we multiply: 4*2 = 8. Case 2: The notepads are all of the same size but of 3 different colors Number of size options = 2. From the 4 ...”
April 18, 2018
GMATGuruNY posted a reply to In a certain coding scheme, each word is encoded by in the Data Sufficiency forum
“Question stem, rephrased: How are the four letters T, A, M and E encoded? Statement 1: Since MAT is encoded as DLX, we get the following chart: ACTUAL LETTER --> ENCODED LETTER M --> D A --> L T --> X No information about the how to encode the letter E. INSUFFICIENT. ...”
April 18, 2018
GMATGuruNY posted a reply to 200 is what percent of 40? in the Problem Solving forum
“To convert a fraction to a percent, multiply the fraction by 100. Question: x is what FRACTION y? Translation: x/y = ? Question: x is what PERCENT of y? Translation: x/y * 100 = ? Thus: 200 is what percent of 40? Translation: 200/40 * 100 = 5* 100 = 500. The correct answer is E.”
April 18, 2018
GMATGuruNY posted a reply to If q is a member of the set {21, 22, 24, 25, 26, 27} in the Data Sufficiency forum
“Statement 1: Here, there are exactly two options for q: Case 1: q=25, since the only prime factor of 25 is 5. Case 2: q=27, since the only prime factor of 27 is 3. Since q can be different values, INSUFFICIENT. Statement 2: Here, there are exactly two options for q: Case 2: q=27, since 27 ...”
April 18, 2018
GMATGuruNY posted a reply to If y is 80 percent greater than x, then x is what percent in the Problem Solving forum
“Let x = 100. Since y is 80% greater than x, y = 100 + (80/100)(100) = 180. x is what percent less than y? In other words: What is the percent decrease from y=180 to x=100? Percent decrease = Difference/Larger * 100 = (180-100)/180 * 100 = 4/9 * 100 = a bit less than 50%. The correct answer ...”
April 18, 2018
GMATGuruNY posted a reply to What is the value of the sum of a list of n odd integers? in the Data Sufficiency forum
“Each statement indicates the same information -- that there are 8 odd integers. Thus, both statements are satisfied by the following cases: Case 1: 1, 1, 1, 1, 1, 1, 1, 1 Case 2: 1, 1, 1, 1, 1, 1, 1, 3 In Case 1, the sum of the 8 odd integers = 8. In Case 2, the sum of the 8 odd integers = 10. ...”
April 18, 2018
GMATGuruNY posted a reply to If the average of p and 4p is 10, then p in the Problem Solving forum
“SUM/COUNT = AVERAGE In the problem above: Sum = p + 4p. Count = 2. Average = 10. Plugging these values into the equation in blue, we get: (4p + p)/2 = 10 5p = 20 p = 4. The correct answer is C.”
April 18, 2018
GMATGuruNY posted a reply to If a/b = 1/2, then the numerical value of which of the in the Problem Solving forum
“An alternate approach is to plug into the five answer choices two cases such that a/b = 1/2: Case 1: a=1 and b=2 Case 2: a=2 and b=4 Note: When the question stem includes the phrase which of the following, the correct answer is likely to be D or E. For this reason, we should start with answer ...”
April 17, 2018
GMATGuruNY posted a reply to When thw integer x is divided by the integer y, the in the Problem Solving forum
“When one positive integer is divided by another, we typically represent what''s left over either as a REMAINDER or as a DECIMAL. There is a relationship between the two representations: Remainder/Divisor = Decimal. When 5 is divided by 2: Remainder representation: 5/2 = 2 R1. Decimal ...”
April 17, 2018
GMATGuruNY posted a reply to Is x>0? in the Data Sufficiency forum
“In Statement 1, the only real solution is x ≈ 1/2, but Statement 2 requires that x<-1 or x>5. Since the two statements contradict each other, the problem is invalid.”
April 17, 2018
GMATGuruNY posted a reply to For the positive integers x, x + 2, x + 4, x + 7, and in the Problem Solving forum
“Let x=1, yielding the following set of values: x = 1 x+2 = 3 x+4 = 5 x+7 = 8 x+12 = 13. Mean = (1+3+5+8+13)/5 = 30/5 = 6. Median = 5. Mean - median = 6-5 = 1. The correct answer is B. Since only one answer choice can be correct, there is no need to test any other values for x.”
April 15, 2018
GMATGuruNY posted a reply to Every delegate to the convention is a party member. Some in the Critical Reasoning forum
“every = ALL. some = AT LEAST ONE. Given information: All delegates to the convention are party members. At least one delegate to the convention is a government official. All government officials at the convention speak at the convention. An alternate approach is to apply the NEGATION ...”
April 15, 2018
GMATGuruNY posted a reply to Nearly two tons of nuclear-reactor fuel in the Sentence Correction forum
“D: The chances...increase greatly with the...increasing amount. Here, increase and increasing are redundant. Eliminate D.”
April 15, 2018
GMATGuruNY posted a reply to Does ab = a^2 in the Data Sufficiency forum
“ab = a² 0 = a² - ab 0 = a(a-b). The resulting equation is valid only if a=0 or a=b. Question stem, rephrased: Does a=0 or a=b? Statement 1: If a=1 and b=1, then the answer to the rephrased question stem is YES. If a=1 and b=-1, then the answer to the rephrased question stem is NO. Since ...”
April 14, 2018
GMATGuruNY posted a reply to Alice is paid at a constant rate of $x per hour for the firs in the Problem Solving forum
“Since Alice works 8 hours after the first 40 hours, she works 8 hours at the $30 rate: 8*30 = 240. Remaining earnings = (total earnings) - (earnings for the last 8 hours) - 920-240 = 680. Since she works 40 hours to earn this $680, her regularly hourly rate = earnings/hours = 680/40 = 17. The ...”
April 14, 2018
GMATGuruNY posted a reply to p>q, Is q negative? in the Data Sufficiency forum
“Statement 1: Case 1: q=1 Substituting q=1 into pq + q² > 0, we get: p(1) + 1² > 0 p > -1. Since this case requires that p>-1, and the prompt requires that p>q, it''s possible that p=2. Thus, a valid combination for Statement 1 is p=2 and q=1, in which case the answer to the ...”
April 14, 2018
GMATGuruNY posted a reply to probability in the Problem Solving forum
“The portion in red is incorrect. From the 5 people, the number of ways to choose 2 = 5C2 = (5*4)/(2*1) = 10. Of the10 possible pairs, only 1 includes Amir and Brian. Thus, P(Amir and Brian are both selected) = 1/10. Alternate approach: P(Amir or Brian is selected on the first pick) = 2/5. ...”
April 14, 2018
GMATGuruNY posted a reply to A rocket soars for 12 seconds at 150 meters per second. in the Problem Solving forum
“Alternate approach: Lower rate = rate upward = 150 meters per second. Higher rate = rate downward = d/t = 600/3 = 200 meters per second. Since the rocket travels 12 seconds upward and 3 seconds downward, the time ratio for the two rates = (12 seconds) : (3 seconds) = 4:1. Implication: Of ...”
April 13, 2018
GMATGuruNY posted a reply to Each of the 50 students participating in a in the Data Sufficiency forum
“Statement 1: Since fewer than 1/2 of the students are female, the probability of picking a female graduate student must be less than 1/2. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: Since fewer than 1/2 of the students are graduate students, the probability of ...”
April 13, 2018
GMATGuruNY posted a reply to Charlie drives 30 miles each way to work and back. in the Problem Solving forum
“Since the distance in each direction is the same, we can plug in ANY VALUE for the distance. Let the distance in each direction = the LCM of 40 and 20 = 40 miles. When Charlie travels the 40-mile distance at 40 mph, the time = d/r = 40/40 = 1 hour. When Charlie travels the 40-mile distance at 20 ...”
April 13, 2018
GMATGuruNY posted a reply to If x > y, is x > 6 ? (1) (x - 7)(y - 7) = 0 (2) x > in the Data Sufficiency forum
“Statement 1: (x - 7)(y - 7) = 0 Case 1: x=7 Here, the answer to the question stem is YES. Case 2: y=7 Substituting y=7 into x > y, we get: x > 7. Thus, the answer to the question stem is YES. Since the answer is YES in both cases, SUFFICIENT. Statement 2: x > 18 - 2y x + 2y > ...”
April 13, 2018
GMATGuruNY posted a reply to Frieda walks 6 feet per second, a pace which is 1/3 as in the Problem Solving forum
“Since Frieda''s rate is 1/3 Evita''s rate, Evita''s rate is 3 times Frieda''s rate: 3*6 = 18 feet per second. Since Evita''s rate is twice Pablo''s rate, Pablo''s rate is 1/2 Evita''s rate: (1/2)(18) = 9 feet per second. How many feet does Pablo walk in an hour? Since Pablo''s rate is 9 feet ...”
April 13, 2018
GMATGuruNY posted a reply to GMATPrep EP2: One key to predicting a competitor's in the Reading Comprehension forum
“The correct answer must be supported by EVERY PARAGRAPH. Paragraph 1: One key to predicting a competitor''s strategies is understanding how much that competitor resembles your company. Paragraph 2: In the fast-food industry, two players faced the same market trends but responded in markedly ...”
April 13, 2018
GMATGuruNY posted a reply to Each letter of a 5-letter password must be a different lette in the Problem Solving forum
“The values in red are incorrect. (21*20*19)/(1*2*3) = 1330.”
April 13, 2018
GMATGuruNY posted a reply to Each letter of a 5-letter password must be a different lette in the Problem Solving forum
“From the 5 slots in the sequence, the number of ways to choose 2 slots for the 2 vowels = 5C2 = (5*4)/(2*1) = 10. Of these 10 options, the following 4 combinations are composed of adjacent slots and thus are not allowed: Slots 1 and 2 Slots 2 and 3 Slots 3 and 4 Slots 4 and 5 Thus: Number of ...”
April 13, 2018
GMATGuruNY posted a reply to When a positive integer n is divided by 5, the remainder is in the Data Sufficiency forum
“When n is divided by 5, the remainder is 2. In other words, n is 2 MORE THAN A MULTIPLE OF 5: n = 5a + 2, where a is a nonnegative integer. Options for n: 2, 7, 12, 17, 22, 27, 32... Statement 1: n is divisible by 2 From the blue list above, even options for n: 2, 12, 22, 32... If n=2, ...”
April 13, 2018
GMATGuruNY posted a reply to 24 computer hackers can scan and infect 10 computers in in the Problem Solving forum
“Use the following equation: (workers)(time) / output = (workers)(time) / output In the equation above: Workers and time are INVERSELY PROPORTIONAL. As the number of workers increases, the amount of time required to produce the same output decreases. Workers and output are DIRECTLY ...”
April 12, 2018
GMATGuruNY posted a reply to GMATPrep EP2: One key to predicting a competitor's in the Reading Comprehension forum
“From the passage: Companies that have different assets, resources, capabilities, and positions within a market will likely also have different responses to market conditions. In the fast-food industry, for example, two players faced the same market trends, resulting from the public''s concerns ...”
April 12, 2018
GMATGuruNY posted a reply to If the elements of set X are a, b, c and d, is the average ( in the Data Sufficiency forum
“SUM = (COUNT)(AVERAGE). Statement 1: Since every pair of elements must have an average of 10, the SUM of every pair of elements = (count)(average) = 2*10 = 20. For every pair to yield a sum of 20, every value in the set must be equal to 10: 10, 10, 10, 10. If any pair of values is selected ...”
April 12, 2018
GMATGuruNY posted a reply to Which of the following is equal to x!/(x+1)! + (x+1)!/(x+2)! in the Problem Solving forum
“Let x=1. Plugging x=1 into the given expression, we get: $$\frac{1!}{\left(1+1\right)!}+\frac{\left(1+1\right)!}{\left(1+2\right)!}= {\frac{1}{2}}{ } + {\frac{1}{3}}{ } = {\frac{5}{6}}{ } $$ The target value is 5/6. Now plug x=1 into the answer choices to see which yields the target value of ...”
April 12, 2018
GMATGuruNY posted a reply to If an organization were to sell n tickets for a theater in the Problem Solving forum
“The number of tickets is irrelevant. If 5% fewer tickets are sold, then the revenue decreases by 5%. Let the cost of the production = 100. If all the tickets are sold, the revenue is 20% more than the cost of the production: 100 + (20% of 100) = 100 + 20 = 120. If 5% fewer tickets are sold, ...”
April 12, 2018
GMATGuruNY posted a reply to After increasing steadily for centuries, in the Sentence Correction forum
“Generally, COMMA + with serves to introduce something that ACCOMPANIES or FACILITATES the preceding action. B: the annual total catch...peaked in 1989, but with the total catch since then Here, the usage of COMMA + but with conveys that the portion in red accompanied the action in blue. This ...”
April 11, 2018
GMATGuruNY posted a reply to Operations with Integers in the Problem Solving forum
“Let $B = the amount spent on bananas and $A = the amount spent on apples. Since each banana sells for 50 cents, we get the following options for $B, in cents: 50, 100, 150, 200... Every value in the list above ends in 50 or 00. Implication: Since $B + $A = 630, $A must end in either 80 or ...”
April 11, 2018
GMATGuruNY posted a reply to Is x^2-y^2>x+y? in the Data Sufficiency forum
“Perfect!”
April 11, 2018
GMATGuruNY posted a reply to Reggie was hiking on a 6-mile loop trail at a rate of 2 in the Problem Solving forum
“Let Reggie travel CLOCKWISE. Since Reggie''s rate = 2 mph, the distance traveled by Reggie in 1 hour = rt = 2*1 = 2 miles. At this point, Cassie can travel clockwise to catch-up to Reggie or counterclockwise to meet him. Test the time required if Cassie travels COUNTERCLOCKWISE, with the result ...”
April 10, 2018
GMATGuruNY posted a reply to Over a three-week period, the price of an ounce of gold in the Problem Solving forum
“Let G = 100. After a 25% increase, the price = 100 + (25/100)(100) = 100 + 25 = 125. After a 20% decrease, the price = 125 - (20/100)(125) = 125 - 25 = 100. After a 5% increase, the price = 100 + (5/100)(100) = 100 + 5 = 105. The question stem asks for the final price: 105. Now plug G=100 ...”
April 10, 2018
GMATGuruNY posted a reply to Evaluate the Argument............OG Diagnostic test in the Critical Reasoning forum
“Premise: Metal rings recently excavated in Mexico were made using the same metallurgical techniques as those used by Ecuadorian artisans. Conclusion: The metallurgical techniques used to make the rings found in Mexico were learned by Mexican artisans from Ecuadorian counterparts. Rephrase the ...”
April 10, 2018
GMATGuruNY posted a reply to Is x>0? in the Data Sufficiency forum
“Statement 1: (x+y)² > (x-y)² x² + y² + 2xy > x² + y² - 2xy 2xy > -2xy 4xy > 0 xy > 0. Implication: x and y have the SAME SIGN. Since x and y could both be positive or both be negative, INSUFFICIENT. Statement 2: x+y > x-y y > -y 2y > 0 y > 0. No ...”
April 10, 2018
GMATGuruNY posted a reply to How many ways could three people sit at a table in the Problem Solving forum
“Let the 3 people be A, B and C. Number of options for A = 5. (Any of the 5 seats.) Number of options for B = 4. (Any of the 4 remaining seats.) Number of options for C = 3. (Any of the 3 remaining seats.) To combine these options, we multiply: 5*4*3 = 60. The correct answer is C.”
April 9, 2018
GMATGuruNY posted a reply to Is x^2-y^2>x+y? in the Data Sufficiency forum
“Question stem, rephrased: Is (x+y)(x-y) > x+y? Statement 1: x - y < 0 If x-y = -1 and x+y = 1, then (x+y)(x-y) = -1 and x+y = 1, so the answer to the question stem is NO. If x-y = -1 and x+y = -1, then (x+y)(x-y) = 1 and x+y = -1, so the answer to the question stem is YES. ...”
April 9, 2018
GMATGuruNY posted a reply to 700-800 Level Manhattan GMAT in the Sentence Correction forum
“COMMA + as compared is a valid construction. An OA in GMATPrep: CEO’s now earn 419 times the pay of blue-collar workers, as compared to 42 times their pay, the ratio in 1980. Proposed revision: Studies of test scores show that watching television has a markedly positive effect on ...”
April 9, 2018
GMATGuruNY posted a reply to A jar contains 4 balls, labeled 1,2,3, and 4. A ball is sel in the Problem Solving forum
“P = (ways to draw 2 balls with a difference of 1)/(total ways to draw 2 balls). Total ways to draw 2 balls: Number of options for the first ball = 4. (Any of the 4 numbers.) Number of options for the second ball = 4. (Any of the 4 numbers.) To combine these options, we multiply: 4*4 = 16. ...”
April 9, 2018
GMATGuruNY posted a reply to Is the sum of 3 positive integers divisible by 6 ? in the Data Sufficiency forum
“Here are a few ways: Only one of the three integers is odd. Exactly one of the three integers is odd. Exactly two of the three integers are even. Only the least of the three integers is odd. Of the three integers, only the greatest is odd.”
April 8, 2018
GMATGuruNY posted a reply to Is the sum of 3 positive integers divisible by 6 ? in the Data Sufficiency forum
“The interpretation in red is incorrect. Statement 1 states only that -- of the 3 positive integers -- the SMALLEST is odd. Statement 2 states only that -- of the 3 positive integers -- the GREATEST is odd. Neither statement indicates that ONLY ONE of the integers is odd.”
April 8, 2018
GMATGuruNY posted a reply to Is the sum of 3 positive integers divisible by 6 ? in the Data Sufficiency forum
“Statements combined: Case 1: The 3 integers are 1, 6, and 11, with the result that the sum of the 3 integers = 1+6+11 = 18 Since 18 is divisible by 6, the answer to the question stem is YES. Case 2: The 3 integers are 1, 5, and 11, with the result that the sum of the 3 integers = 1+5+11 = 17 ...”
April 8, 2018
GMATGuruNY posted a reply to A 45° - 45° - 90° right triangle has hypotenuse of length in the Problem Solving forum
“The sides of a 45-45-90 triangle are in the following ratio: s : s : s√2. Let s=1, implying that h = s√2 = (1)(√2) = √2. In a 45-45-90 triangle, the legs constitute the base and height. Since each leg has a length of 1, we get: Area = (1/2)bh = (1/2)(1)(1) = 1/2. The question stem ...”
April 8, 2018
GMATGuruNY posted a reply to In a certain performance of a 3-act play, the first act was in the Problem Solving forum
“Total number of minutes = (number of acts)(average number of minutes per act) = 3*46 = 138. We can PLUG IN THE ANSWERS, which represent the time for the third act. When the correct answer is plugged in, the total number of minutes = 138. B: 39 minutes Since the first act is 18 minutes shorter ...”
April 8, 2018
GMATGuruNY posted a reply to Set Problem in the Problem Solving forum
“Total who pass = Physics + Chemistry + Math - (exactly 2 subjects) - 2(all 3 subjects). Since 10 of 100 students pass none of the 3 subjects, the total number who pass at least one subject = 100-10 = 90. Of these 90 students, 80 pass Physics, 70 pass Chemistry, and 40 pass Math. Plugging these ...”
April 7, 2018
GMATGuruNY posted a reply to At a particular grade school, there are two math classes in the Data Sufficiency forum
“Statements combined: Case 1: W = 5*5 students and Z = 5*5*9*9 students Here, 5 is the only prime factor common to W and Z, and Z is a multiple of 9 In this case, the GCF of W and Z is 25. Case 2: W = 5*5*5 students, Z = 5*5*5*9*9*9 students Here, 5 is the only prime factor common to W and Z, ...”
April 7, 2018
GMATGuruNY posted a reply to A bag has 4 blue, 3 yellow and 2 green balls. The balls in the Problem Solving forum
“Number of options for the 4 blue balls = 5. (0, 1, 2, 3, or 4 blue balls may be chosen, for a total of 5 options.) Number of options for the 3 yellow balls = 4. (0, 1, 2, or 3 yellow balls may be chosen, for a total of 4 options.) Number of options for the 2 green balls = 3. (0, 1, or 2 green ...”
April 7, 2018
GMATGuruNY posted a reply to A basketball coach will select the members of a five-player in the Problem Solving forum
“Since 5 of the 9 players are included on the team, P(John is included) = 5/9. Since 4 of the remaining 8 players are included on the team, P(Peter is included) = 4/8. To combine the probabilities, we multiply: 5/9 * 4/8 = 5/18. The correct answer is D. Alternate approach: P = (5-member ...”
April 7, 2018
GMATGuruNY posted a reply to If the average (arithmetic mean) price of apples, bananas an in the Data Sufficiency forum
“Sum of the 3 prices = (number of prices)(average price) = 3*3 = $9. Statement 1: A=$3, implying that B+C = 9-3 = $6 Case 1: B=$3 and C=$3, with the result that B+C = $6 In this case, the 3 prices are as follows: $3, $3, $3 Thus, the median price = 3. Case 2: B<$3 and C>$3 or B>$3 ...”
April 7, 2018
GMATGuruNY posted a reply to In how many ways can 3 different portraits be mounted in the Problem Solving forum
“Number of options for the first portrait = 4. (Any of the 4 walls.) Number of options for the second portrait = 3. (Any of the 3 remaining walls.) Number of options for the last portrait = 2. (Either of the 2 remaining walls.) To combine the options above, we multiply: 4*3*2 = 24. The correct ...”
April 7, 2018
GMATGuruNY posted a reply to A company has two models of computers, model M and in the Problem Solving forum
“Let the task = 18 units. Since M takes 18 minutes to complete the 18-unit task, M''s rate = w/t = 18/18 = 1 unit per minute. Since N takes 9 minutes to complete the 18-unit task, N''s rate = w/t = 18/9 = 2 units per minute. Combined rate for M+N = 1+2 = 3 units per minute. For the 18-unit task ...”
April 7, 2018
GMATGuruNY posted a reply to Headway is now targeted at a wider readership - to include a in the Critical Reasoning forum
“The OA is invalid. Passage: Headway is now targeted at a wider readership -- to include all NUT members who are on the leadership salary spine. Implication: Before now, Headway did not include ALL NUT MEMBERS on the leadership salary spine. Since we know only that Headway did not include ALL ...”
April 6, 2018
GMATGuruNY posted a reply to GMATPrep: Quasars are so distant that their in the Sentence Correction forum
“The past perfect (had + VERBed) serves to express an action or state-of-being completed before another past event. B: they had been during the formation of the universe Here, the state-of-being conveyed by the past perfect verb in red is not completed before another past event. Thus, the usage of ...”
April 6, 2018
GMATGuruNY posted a reply to 5 blue marbles, 3 red marbles and 4 purple marbles in the Problem Solving forum
“P(not 2 blue and 2 purple) = 1 - P(exactly 2 blue and exactly 2 purple). P(exactly n times) = P(one way) * total possible ways. P(one way): One way to get exactly 2 blue and exactly 2 purple: BBPP. P(B on the 1st pick) = 5/12. (Of the 12 marbles, 5 are blue.) P(B on the 2nd pick) = 4/11. ...”
April 6, 2018
GMATGuruNY posted a reply to Is x > y? in the Data Sufficiency forum
“Statement 1: If x=1 and y=0, then the answer to the question stem is YES. If x=0 and y=1, then the answer to the question stem is NO. INSUFFICIENT. Statement 2: If x=1 and y=0, then the answer to the question stem is YES. If x=-1 and y=0, then the answer to the question stem is NO. ...”
April 6, 2018
GMATGuruNY posted a reply to Is M<0? in the Data Sufficiency forum
“Statement 1: It''s possible that M=0, in which case the answer to the question stem is NO. It''s possible that M=-1 in which case the answer to the question stem is YES. INSUFFICIENT. Statement 2: If M=3, then the answer to the question stem is NO. If M=-3, then the answer to the question ...”
April 6, 2018
GMATGuruNY posted a reply to In a courtyard, one bell rings every 1/4 hour and another in the Problem Solving forum
“To make the math easier, let the total timeline = the LCM of the two denominators 4 and 5 = 20 minutes. Dividing a 20-minute timeline into 5ths and 4ths, we get: 0....4...5...8...10...12...15...16...20. Each of the values above represents a ring. The timeline yields the following intervals ...”
April 6, 2018
GMATGuruNY posted a reply to Both car A and car B set out from their original locations.. in the Problem Solving forum
“Let t = A'' s time, implying that t+2 = B''s time. Since A''s rate = 65 mph, the total distance traveled by A in t hours = 65t. Since B''s rate = 50 mph, the total distance traveled by B in t+2 hours = 50(t+2). Since B travels BACK AND FORTH, while A travels only in only ONE DIRECTION, B''s total ...”
April 6, 2018
GMATGuruNY posted a reply to If 1.5/(0.2 + x) in the Problem Solving forum
“To clear the decimals, multiply the top and the bottom of the red fraction by 10: 15/(2 + 10x) = 5. Since 15/3 = 5, the expression in blue must be equal to 3: 2 + 10x = 3 10x = 1 x = 1/10. The correct answer is B.”
April 5, 2018
GMATGuruNY posted a reply to A work crew of 4 Men takes 5 days to complete one-half in the Problem Solving forum
“Let the rate for each man = 1 unit per day, implying that the combined rate for 4 men = 4 units per day. Since the rate for the original 4-men crew = 4 units per day, the amount of work produced in the first 5 days = rt = 4*5 = 20 units. Since these 20 units constitute 1/2 the job -- implying that ...”
April 5, 2018
GMATGuruNY posted a reply to Is √x+x>-√y? in the Data Sufficiency forum
“Question stem, rephrased: Is √x + √y + x > 0? Statement 1: Substituting √x+√y = 1 into the rephrased question stem, we get: 1 + x > 0 ? x > -1? Since √x implies that x≥0, the answer to the blue question is YES. SUFFICIENT. Statement 2: Substituting x = POSITIVE into ...”
April 5, 2018
GMATGuruNY posted a reply to The tornado left a path of destruction in its wake, causing in the Sentence Correction forum
“and must serve to connect PARALLEL FORMS. A: the collapse of several homes, massive power outages, tearing apart construction projects, and widespread business closures. Here, the blue portions are all composed of NOUNS and MODIFIERS, while the red portion is composed of a VERBing (tearing ...”
April 5, 2018
GMATGuruNY posted a reply to A troublesome scrub jay in the Sentence Correction forum
“to tend to do X = to be inclined to do X. A scrub jay can remember when it cached a particular piece of food in a particular place and tends not to bother to recover a perishable treat it stored long enough to have rotted. If tends is construed to be parallel with cached, we get the following: ...”
April 4, 2018
GMATGuruNY posted a reply to With the patience of its customers and.......OG2018 in the Sentence Correction forum
“B: with the patience of its customers and its network Case 1: the patience and its network are intended to be parallel, as follows: WITH THE PATIENCE and WITH ITS NETWORK. Case 2: its customers and its network are intended to be parallel, as follows: OF ITS CUSTOMERS and OF ITS NETWORK Case 2 ...”
April 4, 2018
GMATGuruNY posted a reply to OG: Metal rings recently excavated form in the Critical Reasoning forum
“Premise: Metal rings recently excavated in Mexico were made using the same metallurgical techniques as those used by Ecuadorian artisans. Conclusion: The metallurgical techniques used to make the rings found in Mexico were learned by Mexican artisans from Ecuadorian counterparts. Rephrase the ...”
April 4, 2018
GMATGuruNY posted a reply to Car A drives from P to Q at a constant rate of 100 km per ho in the Problem Solving forum
“Since A''s rate is 100 km per hour, the distance traveled by A in the first hour = 100 km. Remaining distance between A and B = (total distance) - (distance traveled by A in the first hour) = 600-100 = 500 km. When A and B drive toward each other, they WORK TOGETHER to cover the remaining 500 km ...”
April 4, 2018
GMATGuruNY posted a reply to Of the goose eggs laid at a certain pond, 2/3 hatched and... in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total number of eggs. When the correct answer is plugged in, the number of geese that survive the first year = 120. The fractions in the prompt -- 2/3, 3/4 and 3/5 -- imply that the correct answer that the correct answer must be a multiple of 3, 4 ...”
April 4, 2018
GMATGuruNY posted a reply to The number of stamps that Kaye and Alberto had were... in the Problem Solving forum
“The answer choices imply that the values in the problem are all MULTIPLES OF 10. Since K:A = 5:3, the following options are implied: K=50, A=30 K=100, A=60 K=150, A=90 K=200, A=120. After K gives away 10 stamps and A receives 10 stamps, the resulting values for K and A must be in a ratio ...”
April 4, 2018
GMATGuruNY posted a reply to With the patience of its customers and.......OG2018 in the Sentence Correction forum
“The phrase in blue is not redundant. One definition of initiative is an action intended to solve a problem. Thus: new initiatives = new actions intended to solve a problem.”
April 3, 2018
GMATGuruNY posted a reply to Five years ago Jim was three times as old as Raoul in the Problem Solving forum
“Test the SMALLEST POSSIBLE CASE. Five years ago Jim was three times as old as Raoul was and Monica was six years older than Raoul was. Let R=1, implying that J = 3R = 3*1 = 3 and that M = R+6 = 1+6 = 7. In this case, their ages 5 years from now -- in other words, 10 years beyond 5 years ago -- ...”
April 3, 2018
GMATGuruNY posted a reply to Is |x−y|>|x+y| ? in the Data Sufficiency forum
“Is |x-y| > |x+y|? When each side of an inequality is an absolute value, we can square the inequality. (x-y)² > (x+y)² x² - 2xy + y² > x² + 2xy + y² 0 > 4xy 0 > xy. The resulting inequality is true only if x and y have different signs. Question stem, rephrased: ...”
April 3, 2018
GMATGuruNY posted a reply to If x and y are positive integer, what is the remainder in the Data Sufficiency forum
“When x is divided by y, the remainder is R. This statement implies the following: x is R more than a multiple of y. Translated into math: x = ky + R, where k is an integer such that k≥0. Statement 1: When x is divided by 2y, the remainder is 4 Case 1: y=3, implying that 2y=6 Here, when x ...”
April 2, 2018
GMATGuruNY posted a reply to Are there more girls than boys at a school? in the Data Sufficiency forum
“Statement 1: (3/7)G > (1/3)B G > (7/3)(1/3)B G > (7/9)B. Case 1: B=9 Substituting B=9 into G > (7/9)B, we get: G > (7/9)(9) G > 7. If G=8, then there are more boys than girls, so the answer to the question stem is NO. If G=10, then there are more girls than boys, so the ...”
April 2, 2018
GMATGuruNY posted a reply to What is the value of x^2 - y^2? in the Data Sufficiency forum
“Statement 1: x+y = 16 If x=8 and y=8, then x² - y² = 8² - 8² = 0. If x=10 and y=6, then x² - y² = 10² - 6² = 64. Since x² - y² can be different values, INSUFFICIENT. Statement 2: x-y = 0, implying that x=y Substituting x=y into x² - y², we get: x² - y² = x² - x² = 0. ...”
April 1, 2018
GMATGuruNY posted a reply to On his morning jog, Charles runs through a park in the in the Problem Solving forum
“rate = distance/time. Let the diameter = 7 meters, implying that the circumference of the semicircle = (πd)/2 = A.”
April 1, 2018
GMATGuruNY posted a reply to By recording the noise of crinkled wrappers as they were in the Sentence Correction forum
“A, C and E: By recording the noise of crinkled wrappers as they were slowly stretched out in an otherwise silent chamber, a team of scientists found the noise. The phrase in red distorts the intended meaning. When the crinkled wrappers were STRETCHED OUT, the noise was not found; it was CREATED. ...”
April 1, 2018
GMATGuruNY posted a reply to In a race of 6 horses A, B, C, D, E and F, what is the prob in the Problem Solving forum
“Within the race, the number of possible orderings for A, B and C = 3! = 6. Since there are 2 orderings in which A appears before both B and C -- ABC and ACB -- we get: P(A appears before both B and C) = 2/6 = 1/3. The correct answer is B.”
April 1, 2018
GMATGuruNY posted a reply to The discovery of glass being expandable and able to be shape in the Sentence Correction forum
“The wording in A indicates that the underlined portion should be extended as follows: A, B and C: The discovery of glass...revolutionized glass-working. This meaning is nonsensical. Whereas the red portion implies that glass was something NEW, the blue portion implies that glass HAD LONG ...”
March 31, 2018
GMATGuruNY posted a reply to Critical points method for inequality Is x^2 > 1/x? in the Data Sufficiency forum
“CRITICAL POINTS occur where an inequality is UNDEFINED and where the two sides are EQUAL. To determine the valid range for an inequality, test one value to the left and right of each critical point. Question stem: x² > 1/x ? Here, the critical points are x=0 (in which case 1/x is undefined) ...”
March 31, 2018
GMATGuruNY posted a reply to In many of the world’s regions, increasing pressure on wat in the Sentence Correction forum
“Generally: NO COMMA + so that serves to introduce the INTENT of the preceding clause. COMMA + so that serves to introduce the CONSEQUENCE of the preceding clause. OA: In many of the world’s regions, increasing pressure on water resources has resulted from expanding development, changes in ...”
March 30, 2018
GMATGuruNY posted a reply to A patient is given exactly 750 millimeters of a mixture of in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the amount of Medication B in the mixture. When the correct answer is plugged in, the amount of painkiller = 215. D: Medication B=425, implying that Medication A = 750-425 = 325 Amount of painkiller = (20% of B) + (40% of A) = 85 + 130 = 215. ...”
March 30, 2018
GMATGuruNY posted a reply to What is the area of the shaded region? in the Problem Solving forum
“Shaded region = (triangle area - sector area)/2 = (12 - sector area)/2 = 6 - (sector area)/2. The expression in blue implies that the correct answer must be A or B. Option A yields a negative value: 6 - 3π ≈ 6 - 9 = -3. The correct answer is B.”
March 30, 2018
GMATGuruNY posted a reply to Health insurance Plan A requires the insured to pay $1000 or in the Problem Solving forum
“Nothing is wrong with C; it is the OA. Several solutions are posted here: https://www.beatthegmat.com/health-insurance-plan-a-requires-the-insured-to-pay-1000-t301243.html”
March 29, 2018
GMATGuruNY posted a reply to Thomas Eakins' powerful style-The present perfect tense coul in the Sentence Correction forum
“Generally: to + NOUN serves to convey DIRECTION. The ball was thrown TO MARY. Conveyed meaning: The ball was thrown in Mary''s direction. for + NOUN serves to convey BENEFIT. Vegetables are good FOR CHILDREN. Conveyed meaning: Children derive BENEFIT from the consumption of vegetables. ...”
March 29, 2018
GMATGuruNY posted a reply to How many different three-digit numbers can be formed which c in the Problem Solving forum
“Integers with exactly 2 digits the same = Total integers - Integers with all 3 digits the same - Integers with all 3 digits different. Total integers: To count consecutive integers, use the following formula: Number of integers = biggest - smallest + 1. Biggest 3-digit integer = 999. Smallest ...”
March 29, 2018
GMATGuruNY posted a reply to In a rare coin collection, one in six coins is gold... in the Problem Solving forum
“Since all of the values in the problem are multiples of 10, the current number of coins is almost certainly a multiple of 10. Since 1 of every six coins is gold, G : S = 1:5, implying that the number of silver coins is 5 times the number of gold coins. Options for G and S: G=10, S=50 G=20, ...”
March 29, 2018
GMATGuruNY posted a reply to In how many ways can the letters of the word ABACUS... in the Problem Solving forum
“Since the vowels must appear together, put them together in a BLOCK: D: (4! * 3!)/2! = 4! * 3. The correct answer is D.”
March 29, 2018
GMATGuruNY posted a reply to Andrew borrows equal sums of money under simple interest... in the Problem Solving forum
“- Let x = the number of months of 5% interest, implying that x+6 = the number of months of 4% interest. Since the amount yielded in each case must be the SAME, we get: 0.05x = 0.04(x+6) 5x = 4(x+6) 5x = 4x + 24 x = 24. Thus, Andrew pays 24 months -- or 2 years -- of 5% interest, for a total ...”
March 28, 2018
GMATGuruNY posted a reply to OG Jacob Burkhardt's view that Renaissance in the Reading Comprehension forum
“Jacob Burckhardt’s view that Renaissance European women “stood on a footing of perfect equality” with Renaissance men has been repeatedly cited by feminist scholars as a prelude to their presentation of rich historical evidence of women’s inequality. A prelude is an INTRODUCTION. ...”
March 28, 2018
GMATGuruNY posted a reply to Under high pressure and intense heat, graphite in the Sentence Correction forum
“and must serve to connect PARALLEL FORMS. A, B and C: graphite changes...and remaining Here, changes (verb) and remaining (modifier) are not parallel forms. Eliminate A, B and C. Generally, in this way refers to the METHOD used to achieve a desired result. D: Under high pressure and intense ...”
March 28, 2018
GMATGuruNY posted a reply to og18: A pioneer journalist, Nellie Bly’s exploits in the Sentence Correction forum
“This SC is discussed at length here: https://www.beatthegmat.com/a-pioneer-journalist-nellie-bly-s-exploits-t278326-15.html”
March 28, 2018
GMATGuruNY posted a reply to Which of the following inequalities is equivalent to in the Problem Solving forum
“Since x=0 satisfies the given inequality, the correct answer must include 0 within its range. Eliminate A, B and D. Since x=2 satisfies the given inequality, the correct answer must include 2 within its range. Eliminate E. The correct answer is C.”
March 28, 2018
GMATGuruNY posted a reply to Is 2x+y>0? in the Data Sufficiency forum
“Both statements are satisfied by the following: Case 1: x=-1 and y=3 Case 2: x=-2 and y=3 In Case 1, 2x+y = 2(-1)+3 = 1, so the answer to the question stem is YES. In Case 2, 2x+y = 2(-2) + 3 = -1, so the answer to the question stem is NO. Since the answer is YES in Case 1 but NO in Case 2, the ...”
March 28, 2018
GMATGuruNY posted a reply to Is i>j? in the Data Sufficiency forum
“Statement 1: Case 1: k=1, j=2 and i=1, with the result that k²j=2 and ki=1 In this case, i < j, so the answer to the question stem is NO. Case 2: k=-1, j=-2 and i=3, with the result that k²j=-2 and ki=-3 In this case, i > j, so the answer to the question stem is YES. Since the answer is ...”
March 27, 2018
GMATGuruNY posted a reply to If function f(x) satisfies f(x)=f(x^2) . . . . in the Problem Solving forum
“Let the function be defined as follows: f(x) = 2. Implication: For any INPUT value, the OUTPUT value will always be 2, with the result that f(x) = f(x²) = 2. Since the output value will always be 2, the answer choices imply the following: A. f(4)=f(2)f(2) --> 2 = 2*2. B. f(16)-f(-2)=0 ...”
March 27, 2018
GMATGuruNY posted a reply to Is x < y? in the Data Sufficiency forum
“Statement 1: No information about x. INSUFFICIENT. Statement 2: No information about y. INSUFFICIENT. Statements combined: Case 1: z=0, y=2 and x=1 In this case, x < y so the answer to the question stem is YES. Case 2: z=0, y=1 and x=2 In this case, x > y, so the answer to the ...”
March 27, 2018
GMATGuruNY posted a reply to If a and b are both positive, what percent of b is a? in the Data Sufficiency forum
“Question: What FRACTION of b is a? In other words: a is what FRACTION of b? Answer: a/b. Question: What PERCENT of b is a? In other words: a is what PERCENT of b? Answer: a/b * 100. To convert the fraction in blue to a percent, we simply multiply by 100. Thus, to answer the question stem ...”
March 27, 2018
GMATGuruNY posted a reply to A code is to be made by arranging 7 letters. Three of the in the Problem Solving forum
“The clause in red seems to imply that repeated letters are IDENTICAL. Thus, the three A''s are identical and the two B''s are identical Number of ways to arrange 7 letters = 7!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of identical ...”
March 27, 2018
GMATGuruNY posted a reply to If x is an integer, is x odd? in the Data Sufficiency forum
“Statement 1: 3x + 3 = odd 3x = odd - 3 3x = odd - odd 3x = EVEN. Since x must be an integer, the resulting equation in blue is true only if x is EVEN. Thus, the answer to the question stem is NO. SUFFICIENT. Statement 2: Since x² is even -- and x must be an INTEGER -- x² must be an ...”
March 27, 2018
GMATGuruNY posted a reply to If u and v are positive real numbers, is u>v? in the Data Sufficiency forum
“The question stem asks whether v < u. As shown in my solution above, v < u would require that u simultaneously be both a fraction and a value greater than 1. Since it is not possible for u to be simultaneously both a fraction and a value greater than 1, we can conclude that v is NOT less ...”
March 26, 2018
GMATGuruNY posted a reply to Sam, Mark and Joe work every day of the week, and each works in the Problem Solving forum
“Alternate approach: Mark worked twice as many hours as Sam. Joe worked three times as many hours as Mark. Let S = 1 hour. Since Mark works twice as many hours as Sam, M = 2*1 = 2 hours. Since Joe works 3 times as many hours as Mark, J = 3*2 = 6 hours. Total work-hours = 1+2+6 = 9. Of the 9 ...”
March 26, 2018
GMATGuruNY posted a reply to How many ways can the five digits 3, 3, 4, 5, 6 be arranged in the Problem Solving forum
“Good arrangements = (all possible arrangements) - (bad arrangements). All possible arrangements: Number of ways to arrange 5 digits = 5! = 120. But the five digits here include two identical 3''s. When an arrangement includes IDENTICAL elements, we must divide by the number of ways each set ...”
March 26, 2018
GMATGuruNY posted a reply to If u and v are positive real numbers, is u>v? in the Data Sufficiency forum
“Since u and v are POSITIVE, the inequalities in the statements can be simplified by multiplying each side by v. Statement 1, rephrased: u³ < v Case 1: u=1 and v=2 In this case, u < v, so the answer to the question stem is NO. Case 2: u=1/2 and v=1/3 In this case, u > v, so the ...”
March 26, 2018
GMATGuruNY posted a reply to OG12: The play La Finestrina in the Critical Reasoning forum
“The correct answer must be supported by the information in the passage. C: In the United States, the training of actors in the twentieth century is based on principles that do not differ radically from those that underlay the training of actors in eighteenth-century Italy The passage offers no ...”
March 25, 2018
GMATGuruNY posted a reply to OG12: The play La Finestrina in the Critical Reasoning forum
“Since the correct answer must be supported by the passage -- implying that the correct answer is a valid INFERENCE that can be drawn from the passage -- the problem above may be considered an inference CR.”
March 25, 2018
GMATGuruNY posted a reply to In a two-month survey of shoppers, each shopper bought one o in the Data Sufficiency forum
“Statement 1: Let the total number of shoppers in the first month = 100, implying 50 X-shoppers and 50 Y-shoppers. Since 90% of the 50 shoppers in red repurchased X in the second month, the red group in the second month yields 45 X-shoppers and 5 Y-shoppers. Since 60% of the 50 shoppers in blue ...”
March 25, 2018
GMATGuruNY posted a reply to Last year 3/5 of the members of a certain club were males. T in the Data Sufficiency forum
“Let the total number of members last year = 50, implying that the number of male members last year = (3/5)(50) = 30. Question stem, rephrased: Is (new total males)/(new total members) > 3/5? Statement 2: New total members = (6/5)(50) = 60, implying that the number of new members = 10. No ...”
March 25, 2018
GMATGuruNY posted a reply to OG18: A long-term study of some 1,000 physicians indicates in the Sentence Correction forum
“Check my posts here: https://www.beatthegmat.com/a-long-term-study-of-some-1-000-physicians-indicates-that-t288311.html”
March 23, 2018
GMATGuruNY posted a reply to In country Z, 10% of the people do not have a university... in the Problem Solving forum
“Let J = job, NJ = no job, D = diploma, ND = no diploma. To organize the data, use the following DOUBLE-MATRIX: https://thumb.ibb.co/cGxPjc/matrix_job_and_diploma_0.png 40% of the people have the job of their choice. The following matrix is yielded: ...”
March 23, 2018
GMATGuruNY posted a reply to A street vendor sells only hot dogs and hamburgers, and at.. in the Problem Solving forum
“Let x = the multiplier for the original ratio and s = the number of hot dogs sold. Original ratio of hot dogs to hamburgers = 2x/x. After s hot dogs are sold, the remaining number of hot dogs = 2x - s. Since the resulting ratio of hot dogs to hamburgers is 1 to 2, we get: (2x-s)/x = 1/2 ...”
March 23, 2018
GMATGuruNY posted a reply to Richard began driving from home on a trip averaging... in the Problem Solving forum
“Since Richard travels alone at 30 mph for 1/2 hour, the distance by which Richard gets ahead = rt = (30)(1/2) = 15 miles. Since Carla is 15 miles behind Richard -- and she must catch up to Richard in 3 hours -- she must catch up by 5 miles each hour. To catch up by 5 miles each hour, Carla must ...”
March 23, 2018
GMATGuruNY posted a reply to Last year, for every 100 million vehicles that traveled on.. in the Problem Solving forum
“3 billion = 3,000,000,000 = 3*10⁹ 100 million = 100,000,000 = 10⁸. The goal is to convert 3*10⁹ vehicles into the correct number of accidents. Since there are 96 accidents for every 10⁸ vehicles, we get: (3*10⁹ vehicles) * (96 accidents)/(10⁸ vehicles) = 3*96*10 = 2880 accidents. ...”
March 22, 2018
GMATGuruNY posted a reply to If a and b are integers and 9 < a < 21 and 19 < b & in the Problem Solving forum
“Since a must be an integer: 10 ≤ a ≤ 20. Since b must be an integer: 20 ≤ b ≤ 30. Greatest option for a/b: (greatest possible a)/(smallest possible b) = 20/20 = 1. Smallest option for a/b: (smallest possible a)/(greatest possible b) = 10/30 = 1/3. Range: (greatest a/b) - ...”
March 22, 2018
GMATGuruNY posted a reply to If the positive integer n is greater than 6, what is in the Data Sufficiency forum
“-A quick lesson on remainders: Onto the problem at hand: Statement 1: In other words, n is 2 more than a MULTIPLE OF 9: n = 9a + 2, where a is nonnegative integer. Options for n: 2, 11, 20, 29... Since n must be greater than 6: If n=11, then dividing by 6 yields a remainder of ...”
March 22, 2018
GMATGuruNY posted a reply to According to the directions on a packet of smoothie mix in the Problem Solving forum
“150 12-ounce smoothies = 150*12 total ounces. Each 3-ounce packet is combined with 12 ounces of water to form one 15-ounce smoothie. Since we must make 150*12 total ounces, and every 15 ounces requires 1 packet, we get: (150*12)/15 = 120 packets. The correct answer is A.”
March 22, 2018
GMATGuruNY posted a reply to Is a + b > c + d? in the Data Sufficiency forum
“Inequalities can be ADDED together as long as the <> in each inequality faces the same direction. Here, d < b can be rephrased as b>d, allowing us to add together a>c and b>d: a+b > c+d.”
March 22, 2018
GMATGuruNY posted a reply to In how many ways can the letters of the word SPENCER be... in the Problem Solving forum
“The posted prompt has a typo: the word SPENCE should actually written as SPENCER, as follows: Since S and P must be together and N and C must be together, consider each pair a SEPARATE BLOCK in the arrangement, yielding the following list of 5 elements: E.”
March 22, 2018
GMATGuruNY posted a reply to Last year a global disturbance of weather patterns disrupted in the Critical Reasoning forum
“Premise: Despite a disruption of weather patterns, the soybean crop increased. Conclusion: The disruption of weather patterns is responsible for an increase in the price of soybeans. The correct answer choice must explain how the disruption of weather patterns has led to an increase in the price ...”
March 22, 2018
GMATGuruNY posted a reply to Pedanius Dioscorides, a first-century physician and botanist in the Sentence Correction forum
“A conjunction such as and must serve to connect PARALLEL FORMS. A: a compilation...and summarizing B: a compilation...and also summarizing D: compiling...and also a summary In these options, the two colored portions connected by and are not parallel forms. Eliminate A, B and D. A COMMA + ...”
March 22, 2018
GMATGuruNY posted a reply to Several people are sitting around a round table playing... in the Problem Solving forum
“Algebraic approach: Let p = the number of people at the table. After the p people at the table each receive c cards -- for a total of pc cards -- the 1 remaining card is given to Martin, with the result that he receives the last card. Since the deck is composed of 50 cards, we get: pc + 1 = ...”
March 22, 2018
GMATGuruNY posted a reply to Two people measure each other's height, the height of the... in the Problem Solving forum
“Alternate approach: Let the average height for the 2 people = 2. Since the difference between the two heights must be equal to the average of 2, L must be 1 LESS THAN 2, and H must be 1 MORE THAN 2, so that L and H are 2 apart from each other. Thus: L = 2-1 = 1. H = 2+1 = 3. H/L = 3/1= 3. ...”
March 21, 2018
GMATGuruNY posted a reply to A side of beef lost 35 percent of its weight in processing.. in the Problem Solving forum
“Always keep your eye on the answer choices. Since the weight loss = 35/100 = 7/20, the original weight decreases by 7/20. Since the resulting weight is an INTEGER VALUE -- 546 -- the original weight must be a MULTIPLE OF 20. Eliminate A, B and C. Since option E -- 1560 pounds -- would have to ...”
March 20, 2018
GMATGuruNY posted a reply to A baseball card decrease in value 20% in its first year... in the Problem Solving forum
“Let the original value of the card = 100. After a 20% decrease, the card = 100 - (20% of 100) = 100 - 20 = 80. After an additional 10% decrease, the card = 80 - (10% of 80) = 80 - 8 = 72. Total decrease = 100 - 72 = 28. Since the card loses $28 of its original $100 value, the total percent ...”
March 20, 2018
GMATGuruNY posted a reply to Machine A can produce balls at a constant rate of 2 balls pe in the Problem Solving forum
“I believe that the following reflects the intent of the problem. Since A''s rate = 2 balls per hour and B''s rate = 3 balls per hour, the combined rate for A+B working together = 5 balls per hour. We can PLUG IN THE ANSWERS, which represent the number of hours A and B work together. Since ...”
March 20, 2018
GMATGuruNY posted a reply to If |x+1/2|=|y+1/2|, what is the value of x+y? in the Data Sufficiency forum
“Case 1: Signs unchanged x + 1/2 = y + 1/2 x = y. Case 2: Signs changed in ONE of the absolute values x + 1/2 = -y - 1/2 x+y = -1 Question stem, rephrased: If x = y or x+y = -1, what is the value of x+y? Statement 1: xy<0 Since x≠y, x+y = -1. SUFFICIENT. Statement 2: x>0 ...”
March 20, 2018
GMATGuruNY posted a reply to If A and B are positive integers greater than 1 such that in the Problem Solving forum
“If A=3*5=15 and B=7*11=77, then I, II, IV, and V are not true. Since I, II, IV and V do not have to be true, eliminate any answer choice that includes I, II, IV and V. Eliminate A, C, D and E. The correct answer is B.”
March 19, 2018
GMATGuruNY posted a reply to 1/3 + 1/2 - 5/6 + . . . . . . . . . in the Problem Solving forum
“$$\frac{1}{3}+\frac{1}{2}−\ \frac{5}{6}+\frac{1}{5}+\frac{1}{4}−\ \frac{9}{20}=\ x$$ $$60(\frac{1}{3}+\frac{1}{2}−\ \frac{5}{6}+\frac{1}{5}+\frac{1}{4}−\ \frac{9}{20})=\ 60x$$ $$20+30-50+12+15-27 = 60x$$ $$0 = 60x$$ $$0 = x$$ The correct answer is A.”
March 19, 2018
GMATGuruNY posted a reply to The sum S of the arithmetic sequence a, a+d,.... in the Problem Solving forum
“For any EVENLY SPACED SET: Count = (biggest - smallest)/(increment) + 1. Average = (biggest + smallest)/2. Sum = (count)(average). The INCREMENT is the difference between successive values. Integers between 1 and 100, inclusive: Here, the integers are CONSECUTIVE, so the increment = 1. ...”
March 19, 2018
GMATGuruNY posted a reply to Given 2x + y + z = 3 and 5x + 3y + z = 8, what is the in the Problem Solving forum
“If we multiply 2x+y+z=3 by 2, we get: 4x+2y+2z=6. If we subtract the equation in blue from 5x+3y+z=8, we get: (5x+3y+z) - (4x+2y+2z) = 8-6 x+y-z = 2. The correct answer is E.”
March 19, 2018
GMATGuruNY posted a reply to square root in the Data Sufficiency forum
“Be definition: √(x²) = |x|. |x-y| is the DISTANCE between x and y. Thus, √(y-4)² = |y-4| = the distance between y and 4. Question rephrased: Is |y-4| = 4-y? In other words: Is the DISTANCE between y and 4 equal to the DIFFERENCE between 4 and y? A DIFFERENCE can be negative, 0, or ...”
March 19, 2018
GMATGuruNY posted a reply to What is the value of t? in the Data Sufficiency forum
“Statements combined: Test easy integer values for t (0, 1, 2, 3, etc.). t(t-1)² = 4t is satisfied by both t=0 and t=3. Since t can be different values, INSUFFICIENT. The correct answer is E.”
March 19, 2018
GMATGuruNY posted a reply to Even though the normal requirements for health and in the Sentence Correction forum
“A and B: their soldiers Here, their (plural) seems to refer to requirements (plural) or to health and marksmanship (also plural), but the intention is for their to refer to the reserve battalions. Since the other answer choices avoid this ambiguity, eliminate A and B. C and D: all their ...”
March 18, 2018
GMATGuruNY posted a reply to If 0<2x+3y<50 and −50<3x+2y<0 , then which of in the Problem Solving forum
“To eliminate x from the two inequalities, multiply the first by 3 (to yield 6x) and the second by -2 (to yield -6x) and then ADD the resulting inequalities: 0<2x+3y<50 --> 0<6x+9y<150 -50<3x+2y<0 --> 100>-6x-4y>0 --> 0<-6x-4y<100 Adding together the ...”
March 18, 2018
GMATGuruNY posted a reply to If 0<2x+3y<50 and −50<3x+2y<0 , then which of in the Problem Solving forum
“Here, the blue inequalities yielded by x=-1 are both satisfied by y=1, implying that x=-1 and y=1 constitute a valid solution for 0<2x+3y<50 and -50<3x+2y<0. Thus, it does NOT have to be true that x>0. Here, no value for x will satisfy the blue inequalities yielded by y=-1, ...”
March 18, 2018
GMATGuruNY posted a reply to Which of the following fractions expressed in the form in the Problem Solving forum
“P/Q ≈ 0.PQ P/Q ≈ (PQ)/100 100P ≈ Q * PQ The correct value for P/Q must satisfy the approximation in blue. A: 100*1 ≈ 8*18 B: 100*2 ≈ 9*29 C. 100*3 ≈ 4*34 D. 4*100 ≈ 5*45 E: 8*100 ≈ 9*89 Only E yields a valid approximation. The correct answer is E.”
March 18, 2018
GMATGuruNY posted a reply to Set T consist of 19 elements. The average of set T is L. in the Problem Solving forum
“The goal is to plug in easy numbers for L and K. Let L = 2. Sum of the original 19 numbers = (count)(average) = 19*2 = 38. Let K = 50, implying that the average increases 50% from 2 to 3. Since the average of the resulting set of 20 numbers = 3, the sum of the resulting set of twenty numbers = ...”
March 17, 2018
GMATGuruNY posted a reply to Set T consist of 19 elements. The average of set T is L. in the Problem Solving forum
“Let L = 10 and the added element = 10. Since the added element (10) is equal to the original average (also 10), the average for the set DOES NOT CHANGE when the new element is added, with the result that K=0%. The question stem asks for the value of the added element: 10. Now plug L=10 and K=0 ...”
March 17, 2018
GMATGuruNY posted a reply to John and Peter are among the nine players a basketball... in the Problem Solving forum
“One approach: From the 9 players, 5 are to be selected for the team. P(john is selected) = 5/9. From the 8 remaining players, 4 are to be selected for the team. P(Peter is selected) = 4/8. Multiplying the probabilities, we get: 5/9 * 4/8 = 5/18. The correct answer is D. An ...”
March 17, 2018
GMATGuruNY posted a reply to For over two centuries, no one had been able to make Damascu in the Critical Reasoning forum
“B does not imply that there was no production of Damascus blades. B: The iron with which the contemporary sword maker made Damascus blades came from a source of iron that was unknown two centuries ago. Here, the iron used by the contemporary sword maker was unknown to Damascus sword makers, ...”
March 16, 2018
GMATGuruNY posted a reply to Last Sunday a certain store sold copies of newspaper a for.. in the Problem Solving forum
“Plug in values that make the math easy. Let the number of copies of B sold = 4, so that the revenue from B = 4(1.25) = 5. Let the number of copies of A sold = 4, so that the revenue from A = 4*1 = 4. Since (copies of A)/(total copies) = 4/8 = 1/2, p = (1/2)100 = 50. Since (revenue from ...”
March 16, 2018
GMATGuruNY posted a reply to Some anthropologists believe that the genetic homogeneity in the Sentence Correction forum
“A COMMA + VERBing modifier is attributed to the SUBJECT of the preceding clause. In A, reducing seems to refer to our ancestors, implying that OUR ANCESTORS were greatly reducing their numbers. Not the intended meaning: our ancestors did not reduce their own numbers. The intended meaning is that ...”
March 16, 2018
GMATGuruNY posted a reply to If a right triangle has a hypotenuse that is twice the in the Problem Solving forum
“The sides of a 30-60-90 triangle are in the following ratio: x : x√3 : 2x Since the hypotenuse = 2x and the shortest side = x, the hypotenuse is twice the shortest side. No other right triangle has a hypotenuse that is twice the shortest side. Since the triangle must be a 30-60-90 ...”
March 16, 2018
GMATGuruNY posted a reply to If x, y are integers, is x+y an odd number? in the Data Sufficiency forum
“Parity = the state of being EVEN or ODD. x+y = ODD only if x and y have different parities (one is even, while the other is odd). Question stem, rephrased: Do x and y have different parities? Statement 1: Case 1: x = EVEN In this case, y = 3(EVEN) + 5 = EVEN + ODD = ODD. Here, x and y have ...”
March 16, 2018
GMATGuruNY posted a reply to In how many ways can N students be seated in a row with in the Data Sufficiency forum
“The number of ways to arrange N students = N!. Thus, to answer the question stem, we need to know the value of N. Question stem, rephrased: What is the value of N? Statement 1: If N-6 = 3, then N=9. If N-6 = -3, then N=3. Since N can be different values, INSUFFICIENT. Statement 2: N² - ...”
March 16, 2018
GMATGuruNY posted a reply to When a random experiment is conducted, the probability in the Problem Solving forum
“P(exactly n times) = P(one way) * (total number of ways). Let Y = the probability that the event occurs and N = the probability that the event does NOT occur. P(one way): One way to get exactly two Y''s over 5 experiments: YYNNN. P(YYNNN) = 1/3 * 1/3 * 2/3 * 2/3 * 2/3 = 8/243. Total ...”
March 16, 2018
GMATGuruNY posted a reply to If x > 0, what is the value of x? in the Data Sufficiency forum
“Statement 1: Since x can be any value greater than 5, INSUFFICIENT. Statement 2: 36 - x² = 0 36 = x² x = ±6. Since the prompt indicates that x>0, the only viable solution is x=6. SUFFICIENT. The correct answer is B.”
March 16, 2018
GMATGuruNY posted a reply to Each student at a certain business school is assigned a in the Problem Solving forum
“Number of options for the 1st digit = 9. (Any digit 1 through 9) Number of options for the 2nd digit = 10. (Any digit 0 through 9) Number of options for the 3rd digit = 10. (Any digit 0 through 9) Number of options for the 4th digit = 4. (Must be 2, 3, 5 or 7) To combine the options above, we ...”
March 16, 2018
GMATGuruNY posted a reply to Kim finds a 1-meter tree branch and marks it off in... in the Problem Solving forum
“Ignore the given length of 1-meter. The problem can be solved using any length. Let length = 15 meters. Dividing 15 into 3rds will yield markings at 5 and 10. Dividing 15 into 5ths will yield markings at 3, 6, 9, and 12. Listing the markings in order: ...”
March 16, 2018
GMATGuruNY posted a reply to If the center of a circle lies on a smaller circle... in the Problem Solving forum
“Let the diameter of the larger circle = 4, implying that the diameter of the smaller circle = 2. Area of the larger circle = πr² = π(2)² = 4π. Area of the smaller circle πr² = π(1)² = π. Area of the unshaded portion = larger circle - smaller circle = 4π - π = 3π. Thus: (unshaded ...”
March 16, 2018
GMATGuruNY posted a reply to The scoring system in a certain football competition... in the Problem Solving forum
“Since 9 points have been earned after 5 games, the team must earn 31 more points over the next 15 games to reach the 40-point mark. We can PLUG IN THE ANSWERS, which represent the least number of games that must be won. To MINIMIZE the number of wins, we must MAXIMIZE the number of points earned ...”
March 15, 2018
GMATGuruNY posted a reply to Health insurance Plan A requires the insured to pay $1000... 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 ...”
March 14, 2018
GMATGuruNY posted a reply to If triangle ABC is right angled at vertex A in the Data Sufficiency forum
“Since the right angle is at vertex A, AB and AC constitute the legs -- and thus are the base and the height -- of the triangle. Thus: Area = (1/2)(AB)(AC). To calculate the area, we need to know the value of the product in blue. Question stem, rephrased: What is the value of (AB)(AC)? ...”
March 14, 2018
GMATGuruNY posted a reply to In these difficult economic times, those who have---Veriats in the Sentence Correction forum
“In A, the referent for they is unclear. Eliminate A. C: those who have public pensions...operate without much oversight from banking regulators but are now drawing scrutiny from several other government organizations D: those who have public pensions...operating without much oversight from ...”
March 14, 2018
GMATGuruNY posted a reply to Out of 75 students, 17 students enrolled in a Physics class, in the Problem Solving forum
“We can use the following formula: Total = Group 1 + Group 2 + Group 3 - (at least 2 groups) + (all 3 groups) + None. In the problem above: Total = 75. Group 1 = physics = 17. Group 2 = chemistry = 28. Group 3 = biology = 39. At least 2 groups = (physics and biology) + (chemistry and ...”
March 14, 2018
GMATGuruNY posted a reply to A grocery store sells apples by the pound. If the price per in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the current price per pound. When the current price per pound increases by $1, the number of pounds that can be purchased with $12 decreases by 0.4 -- implying that the number of pounds that can be purchased with $120 must decrease by 4. The reasoning ...”
March 13, 2018
GMATGuruNY posted a reply to Is (x-1)^3< (x-1)? in the Data Sufficiency forum
“a³ < a if a < -1 or 0 < a < 1. By extension, (x-1)³ < (x-1) in the following cases: Case 1: x-1 < -1, with the result that x < 0 Case 2: 0 < x-1 < 1, with the result that 1 < x < 2 Question stem, rephrased: Is x < 0 or 1 < x < 2? Statement 1: x ...”
March 13, 2018
GMATGuruNY posted a reply to OG13 117 CR Northern Air has dozens of flights daily into an in the Critical Reasoning forum
“Like a road, a runway must be SHARED. Common sense tells us Skybuses at Belleville Airport will have to share the airport''s runways with OTHER PLANES -- especially given that the airport is highly congested. Whether these other planes are owned by Northern Air or by other airlines is irrelevant. ...”
March 12, 2018
GMATGuruNY posted a reply to Native American burial sites dating back 5,000 years in the Sentence Correction forum
“OA: Residents of Maine...were part of a widespread culture. The sentence above is correct. The SC above is featured in the OG10. An OA from GMAC is -- by definition -- correct as written.”
March 12, 2018
GMATGuruNY posted a reply to The king of Scotland in the early 14th century was the great in the Sentence Correction forum
“On reason to eliminate E: COMMA + with the results that is unidiomatic. Correct: COMMA + with the result that For an OA with this idiom, check here: https://www.beatthegmat.com/as-the-honeybeea-s-stinger-t81041.html”
March 12, 2018
GMATGuruNY posted a reply to A man is a climbing up a 100-foot high mountain. Each day... in the Problem Solving forum
“Look for a PATTERN. Every day the man climbs 20 feet from the height of the preceding day, then falls 20 feet. 1st day --> climb = 0+30 = 30, fall = 30-20 = 10. 2nd day --> climb = 10+30 = 40, fall = 40-20 = 20. 3rd day --> climb = 20+30 = 50, fall = 50-20 = 30. As indicated by the ...”
March 12, 2018
GMATGuruNY posted a reply to If x>0 and √5x = √3x+1, what is the value of 4x^2? in the Problem Solving forum
“We should ALWAYS keep our eyes on the answer choices. In the posted problem, none of the answers include √, so we should perform algebra that will eliminate this symbol. Squaring the equation in red will not eliminate the √ from the right side. Before squaring, we should isolate the ...”
March 12, 2018
GMATGuruNY posted a reply to If x + y > 0, is xy^2 + x^2y > 0? in the Data Sufficiency forum
“Since x+y>0, the inequality in the question stem can safely be divided by x+y, as follows: xy² + x²y > 0 xy(y + x) > 0 Statement 1: x>y Case 1: x=2 and y=1, satisfying the constraints that x+y > 0 and x>y In this case, xy > 0, so the answer to the rephrased question stem ...”
March 12, 2018
GMATGuruNY posted a reply to If (n+2)!= n!(an^2+bn+c), then abc=? in the Problem Solving forum
“(n+2)! = n!(an² + bn + c) (n+2)!/n! = an² + bn + c D.”
March 12, 2018
GMATGuruNY posted a reply to If x>0 and √5x = √3x+1, what is the value of 4x^2? in the Problem Solving forum
“Since none of the answer choices contains a √, perform algebra that will clear the √ symbols: √(5x) = √(3x) + 1 E.”
March 11, 2018
GMATGuruNY posted a reply to If x and y are two-digit integers such that x > 40 in the Problem Solving forum
“Since x and y are two-digit integers such that x>40 and y<70: 40 < x ≤ 99. 10 ≤ y < 70. Thus: Maximum possible value for x = 99. Maximum possible value for y = 69. Maximum possible value for xy = 99*69 = (100-1)(70-1) ≈ 100*70 = 7000. The correct answer is D.”
March 11, 2018
GMATGuruNY posted a reply to OG13 117 CR Northern Air has dozens of flights daily into an in the Critical Reasoning forum
“It is stated as a PREMISE that the Skybus'' fuel efficiency results in LOWER FUEL COSTS. A premise is a FACT. It cannot be disputed or weakened. Thus, the price of fuel is irrelevant. Whatever the price of fuel, the Skybus'' fuel efficiency will still result in LOWER fuel costs, since this ...”
March 11, 2018
GMATGuruNY posted a reply to Sentence Correction in the Sentence Correction forum
“A plural subject can be equated with a singular noun. John and Mary are a good team. Here, John and Mary (plural subject) are equated with a good team (singular). The verb (are) is plural because the subject (John and Mary) is plural. OA: Pollution and degradation...are a matter of universal ...”
March 11, 2018
GMATGuruNY posted a reply to Traffic safety officials predict that drivers will be equall in the Sentence Correction forum
“Check my posts here: https://www.beatthegmat.com/traffic-safety-t97680.html”
March 11, 2018
GMATGuruNY posted a reply to During the Great Depression in the Sentence Correction forum
“OA: Industrial output fell by nearly fifty percent Here, nearly is an adverb serving to modify by fifty percent. I recommend that you classify words such as nearly, only, and almost as LIMITERS. A limiter is a modifier that serves to LIMIT the scope of another word. Generally, a limiter should ...”
March 11, 2018
GMATGuruNY posted a reply to As the etched lines on computer memory chips have become in the Sentence Correction forum
“ELLIPSIS = the omission of words whose presence is understood. OA: As the etched lines on computer chips have become thinner and the chips'' circuits more complex Here, the verb in brackets is omitted but implied -- an example of ellipsis. The implied verb is understood because the two clauses ...”
March 11, 2018
GMATGuruNY posted a reply to A jury pool consists of 6 men and w women. If 2 jurors are s in the Data Sufficiency forum
“Statement 1: Case 1: w=3, for a total of 9 people (6 men and 3 women) From the 6 men, the number of ways to choose 2 = 6C2 = (6*5)/(2*1) = 15. From the 9 people, the number of ways to choose 1 man and 1 woman = (number of options for the 1 man)(number of options for the 1 woman) = 6*3 = 18. ...”
March 10, 2018
GMATGuruNY posted a reply to If n is a 27-digit positive integer, all of whose digits in the Problem Solving forum
“An integer is a multiple of 9 if its digit sum is a multiple of 9. Test the smallest possible case: Let n = 111, 111,111...111,111,111, where all 27 digits are 1. Since there are 27 digits of 1, the sum of the digits = 27*1 = 27. Since the digit sum is a multiple of 9, n is divisible by 9. ...”
March 10, 2018
GMATGuruNY posted a reply to Comparison SC in the Sentence Correction forum
“A: Approximately 75 million people visit France every year, more than any other country. Here, the red portion seems to convey that 75 million people are more than any other country or that France is more than any other country. Neither meaning makes sense. Eliminate A. C: Approximately 75 ...”
March 10, 2018
GMATGuruNY posted a reply to If Q is a set of consecutive integers, what is the in the Data Sufficiency forum
“SD describes how much a set of data DEVIATES from the mean. For any set of of consecutive integers, the mean = the median. Question rephrased: How do the integers in set Q deviate from the median? Statement 1: Set Q contains 21 terms. Any set of 21 consecutive integers will deviate from the ...”
March 9, 2018
GMATGuruNY posted a reply to At the beginning of a class, a classroom has 3 empty chairs in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of chairs. Since there are 3 empty chairs at the beginning of class, the original number of students is 3 less than the correct answer choice. Since the original number of students increases by 20% = 1/5, the original number of students must ...”
March 9, 2018
GMATGuruNY posted a reply to A circular mat with diameter 20 inches is placed... in the Problem Solving forum
“Circle area = πr² = π(10²) ≈ 3*100. Square area = 24*24. (circle)/(square) ≈ (3*100)/(24*24) = (3*2*2*25)/(3*2*2*2*24) = 25/48 ≈ 24/48 = 1/2. The correct answer is C.”
March 9, 2018
GMATGuruNY posted a reply to Is xy > 16? in the Data Sufficiency forum
“Both statements are satisfied by the following cases: Case 1: x=2 and y=20, with the result that xy > 16. Case 2: x=-2 and y=20, with the result that xy < 16. Since the answer is YES in Case 1 but NO in Case 2, the two statements combined are INSUFFICIENT. The correct answer is E.”
March 9, 2018
GMATGuruNY posted a reply to A car traveled 462 miles per tankful of gasoline on the high in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the miles per gallon in the city. Since the car drove 6 fewer miles per gallon in the city than on the highway, the highway rate must be 6 greater than the tested answer choice. When the correct answer choice is plugged in, the same amount of gas -- in ...”
March 9, 2018
GMATGuruNY posted a reply to OG: While it costs about the same to run nuclear in the Sentence Correction forum
“A and C: the fixed costs...that makes Here, makes (singular) does not agree with costs (plural). Eliminate A and C. In D and E, it is unclear whether they serves to refer to nuclear plants or to other types of power plants. Since B is free of errors and avoids this ambiguity, eliminate D and ...”
March 8, 2018
GMATGuruNY posted a reply to Although the ratio of physicians to total population in the Critical Reasoning forum
“Premise: The US has a higher ratio of surgeons per capita, and Americans undergo 40% more surgeries than Canadians. Conclusion: In the US, the greater number of surgeries is due to the higher ratio of surgeons per capita. Apply the NEGATION TEST. When the correct answer is negated, the ...”
March 8, 2018
GMATGuruNY posted a reply to Quickest Way to do this GMAT Diagnostic Test Question in the Problem Solving forum
“Since the answer choices are VERY spread out, we can BALLPARK. For every value that we round UP, we should compensate by rounding another value DOWN. 2*3*5*7*11*13*17*19 210 * 10*15 * 15*20 200*150*300 = 9,000,000. The closest power of 10 = 10,000,000 = 10⁷. The correct answer is C.”
March 8, 2018
GMATGuruNY posted a reply to Steve traveled the first 2 hours of his journey... in the Problem Solving forum
“2 hours are spent at 40mph. 3 hours are spent at 80mph. Average speed for all 5 hours = (2*40 + 3*80)/5 = 320/5 = 64. The correct answer is D.”
March 8, 2018
GMATGuruNY posted a reply to If xy does not equal zero, what is the value of xy in the Data Sufficiency forum
“Statement 1: 2/x + 2/y = 3 2/x = 3 - 2/y Case 1: y=1 Plugging y=1 into 2/x = 3 - 2/y, we get: 2/x = 3 - (2/1) 2/x = 1 2 = x xy = 2*1 = 2. Case 2: y=-1 Plugging y=-1 into 2/x = 3 - 2/y, we get: 2/x = 3 - (2/-1) 2/x = 5 2/5 = x xy = (2/5)(-1) = -2/5. Since xy can be different ...”
March 8, 2018
GMATGuruNY posted a reply to There are three parallel straight lines in the Problem Solving forum
“From the 6 points, ANY COMBINATION OF 3 can serve to form a triangle. Thus: Maximum number of triangles that can be formed from the 6 points = number of ways to choose 3 points from 6 options = 6C3 = (6*5*4)/(3*2*1) = 20. The correct answer does not seem to be among the answer choices. What is ...”
March 7, 2018
GMATGuruNY posted a reply to On a railway route between two places A and B, there are 10 in the Problem Solving forum
“Current number of ticket options: There are currently 12 stops: A, B, and the 10 stops between them. Number of options for the departure stop = 12. Number of options for the arrival stop = 11. To combine these options, we multiply: 12*11 = 132. New number of ticket options: After 4 stops ...”
March 7, 2018
GMATGuruNY posted a reply to Pat, Kate and Marck charged a total of 162 hours of... in the Problem Solving forum
“Test the SMALLEST POSSIBLE CASE. Let M = 6. Since Pat charged 1/3 as much as Mark, P = (1/3)(6) = 2. Since Pat charged twice as much as Kate, Kate''s amount is 1/2 Pat''s amount: K = (1/2)(2) = 1. Smallest possible total = 6+2+1 = 9. Since (actual total)/(smallest possible total) = 162/9 ...”
March 7, 2018
GMATGuruNY posted a reply to A draining pipe can empty a pool in 4 hours in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the capacity of the pool. When the correct answer is plugged in, the time to empty the pool when the draining pipe and intake pipe work simultaneously = 6 hours. The correct answer is likely to be divisible by the given times and rates (4 hours, 6 hours, ...”
March 7, 2018
GMATGuruNY posted a reply to If (x^3 - 2x^2 + x - 1)^2 - 1=(x - a) (x - b) (x - c) (x - d in the Problem Solving forum
“We are asked to determine the value of abcdef. If x=0, then x disappears from the right side of the question, leaving only the value of abcdef -- the very value that we seek to determine. For this reason, it makes sense to test x=0. As shown in my solution above: When x=0, abcdef = 0. Since ...”
March 6, 2018
GMATGuruNY posted a reply to If (x^3 - 2x^2 + x - 1)^2 - 1=(x - a) (x - b) (x - c) (x - d in the Problem Solving forum
“Let x=0. Plugging x=0 into (x³ - 2x² + x - 1)² - 1=(x - a)(x - b)(x - c)(x - d)(x - e)(x - f), we get: (0 - 1)² - 1 = (-a)(-b)(-c)(-d)(-e)(-f) 1 - 1 = abcdef 0 = abcdef. The correct answer is A.”
March 6, 2018
GMATGuruNY posted a reply to 10 members of a society, including members A and B, attended in the Problem Solving forum
“P(A or B is the first person selected) = 2/10. (Of the 10 people, 2 are A or B.) P(A or B is the second person selected) = 1/9. (Of the 9 remaining people, 1 is A or B). Since we want both events to happen, we MULTIPLY the probabilities: (2/10)(1/9) = 1/45. The correct answer is E. ...”
March 6, 2018
GMATGuruNY posted a reply to Under high pressure and intense heat, graphite in the GMAT Verbal & Essays forum
“and must serve to connect PARALLEL FORMS. A, B and C: graphite changes...and remaining Here, changes (verb) and remaining (modifier) are not parallel forms. Eliminate A, B and C. Generally, in this way refers to the METHOD used to achieve a desired result. D: Under high pressure and intense ...”
March 6, 2018
GMATGuruNY posted a reply to What is x? in the Data Sufficiency forum
“Statement 1: Here, x can be any value between -2 and 2. INSUFFICIENT. Statement 2: Case 1: signs unchanged x = 3x - 2 2 = 2x 1 = x x = 1. Case 2: signs changed in the absolute value -x = 3x - 2 2 = 4x 2/4 = x x = 1/2. When an equation has absolute value only ON ONE SIDE, plug the ...”
March 6, 2018
GMATGuruNY posted a reply to Using Double Matrix method--Felixity, a musician, never sing in the Data Sufficiency forum
“The conclusion in red is not justified. If we solve the equation for the center box, we get: 20 - x = 25 - (x+5) 20 - x = 25 - x - 5 20 - x = 20 - x 0 = 0. The resulting equation in blue tells us nothing about the value of x.”
March 6, 2018
GMATGuruNY posted a reply to Using Double Matrix method--Felixity, a musician, never sing in the Data Sufficiency forum
“Use a DOUBLE-MATRIX to organize the data. Every song is either ROCK or NOT ROCK. Every song is either SAD or NOT SAD. According to the prompt: Total not sad = 20. Total not rock = 25. Since Felixity never sings sad rock songs, both sad and rock = 0. The following matrix is yielded: ...”
March 5, 2018
GMATGuruNY posted a reply to A magician has five animals in his magic hat in the Problem Solving forum
“Alternate approach: From the 5 animals, the total number of ways to select a pair = 5C2 = (5*4)/(2*1) = 10. Number of ways to choose a NON-MATCHING PAIR = (number of dove options)(number of rabbit options) = 3*2 = 6. Since 6 of the 10 possible pairs are non-matching, the number of MATCHING ...”
March 5, 2018
GMATGuruNY posted a reply to The closing price of Stock X changed on each trading in the Problem Solving forum
“Let f = the price on the first day. The percent change from the first trading day to each of the other trading days was less than 50 percent. Thus, the percent change from f to the price on the second day -- $10 -- must be less than 50%. We must determine the range of f. To calculate the ...”
March 5, 2018
GMATGuruNY posted a reply to Running at their respective constant rates, machine X takes in the Problem Solving forum
“Let w = 60 widgets, implying that (5/4)w = (5/4)(60) = 75 widgets. Since X and Y together can produce (5/4)w widgets in 3 days, the combined rate for X and Y = w/t = 75/3 = 25 widgets per day. We can PLUG IN THE ANSWERS, which represent X''s time to produce 2w widgets. When the correct answer ...”
March 5, 2018
GMATGuruNY posted a reply to GMAT Question Pack 1 - modulus & inequality in the Data Sufficiency forum
“Nice work!”
March 5, 2018
GMATGuruNY posted a reply to Inequality!! in the Data Sufficiency forum
“Determine the CRITICAL POINTS. Statement 1: a³ - a < 0. a(a+1)(a-1) < 0. The critical points are a=0, a=-1, a=1. These are the only values where a(a+1)(a-1) = 0. When a is any other value, a(a+1)(a-1) < 0 or a(a+1)(a-1) > 0. To determine the range of a, test one value to the ...”
March 5, 2018
GMATGuruNY posted a reply to GMAT Question Pack 1 - modulus & inequality in the Data Sufficiency forum
“|xy| > x²y² ? Since neither an absolute value not the square of a value can be negative, both sides are of the inequality above are NONNEGATIVE. Thus, we can safely square the inequality: x²y² > x⁴y⁴. Since the resulting inequality is valid only if x and y are NONZERO, we can now ...”
March 5, 2018
March 4, 2018
GMATGuruNY posted a reply to Because an oversupply of computer chips has sent prices in the Sentence Correction forum
“In D and E, due to seems to refer to the manufacturer, implying that THE MANUFACTURER was DUE to plunging computer chip prices (in D) or to an oversupply (in E). These meanings are nonsensical. Eliminate D and E. which + SINGULAR VERB must serve to refer to a singular antecedent. In B, which ...”
March 4, 2018
GMATGuruNY posted a reply to If a bowl contains only white and black balls, what is the in the Data Sufficiency forum
“Statement 1: Of every 3 balls, 1 is black and 2 are white. Thus, the probability of extracting a white ball = 2/3. SUFFICIENT. Statement 2: Implication: The bowl contains at most 1 black ball, with the result that it is not possible to extract 2 black balls from the bowl. Case 1: 1 black ...”
March 4, 2018
GMATGuruNY posted a reply to Alex paid a $12 fee to receive a 10% discount off in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the list price. When the correct answer is plugged in, Alex and Victor pay the same amount. B: 60 Since Alex receives a 10% discount for a $12 fee, the amount paid by Alex = 60 - (10% of 60) + ($12 fee) = 60-6+12 = 66. Since Victor receives a 15% ...”
March 4, 2018
GMATGuruNY posted a reply to The ancient Nubians inhabited an area in which typhus occurs in the Critical Reasoning forum
“Premise: Tetracycline can flourish on the dried grain used for making beer and bread. Conclusion: Tetracycline explains the low incidence of typhus among ancient Nubians. Apply the NEGATION TEST. When the correct answer is negated, the conclusion will be invalidated. B, negated: ...”
March 3, 2018
GMATGuruNY posted a reply to A can complete a certain job in 12 days in the Problem Solving forum
“Since B is 60% more efficient that A, we get: B''s rate = (160/100)(A''s rate) = (8/5)(A''s rate). Rate and time have a RECIPROCAL RELATIONSHIP. Since B''s rate is 8/5 of A''s rate, B''s time is 5/8 of A''s time: (5/8)(12) = 15/2 = 7.5 days. The correct answer is D.”
March 3, 2018
GMATGuruNY posted a reply to OG: In 1923, the Supreme Court declared a minimum wage in the Sentence Correction forum
“and must serve to connect PARALLEL FORMS. A and B: declared...and ruling Here, declared (verb) and ruling (modifier) are not parallel forms. Eliminate A and B. COMMA + VERBing must refer to the preceding SUBJECT. D: A minimum wage...was declared unconstitutional by the Supreme Court, ruling ...”
March 3, 2018
GMATGuruNY posted a reply to If every boy in a kindergarten class buys a soda and. . . . in the Problem Solving forum
“The case above is not viable. Since S and J represent the price in cents, they must be positive integers. It is not possible that the price of a soda is 1/2 cent.”
March 3, 2018
GMATGuruNY posted a reply to A drink holding 6 ounces of an alcoholic drink that... in the Problem Solving forum
“6 ounces of an alcoholic drink is 1 part rum to 2 parts coke. Since rum : coke = 1:2 = 2:4, this drink is composed of 2 ounces of rum and 4 ounces of coke, for a total of 6 ounces. 32 ounces of an alcoholic drink that is 1 part rum to 3 parts coke Since rum : coke = 1:3 = 8:24, this drink is ...”
March 3, 2018
GMATGuruNY posted a reply to If 9^y + 3^b = 10*3^b, then 2y =' in the Problem Solving forum
“So that all of the terms with exponents have the same base, let b=2. Plugging b=9 into 9^y + 3^b = 10(3^b), we get: 9^y + 3² = 10(3²) 9^y + 9 = 10*9 9^y + 9 = 90 9^y = 81 y =2, with the result that 2y = 2*2 = 4. The question stem asks for the value of 2y (4). Now plug b=2 into the ...”
March 2, 2018
GMATGuruNY posted a reply to If every boy in a kindergarten class buys a soda and. . . . 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 ...”
March 2, 2018
GMATGuruNY posted a reply to Two motorists start a journey at opposite ends of the state in the Problem Solving forum
“When A and B travel toward each other, they WORK TOGETHER to cover the 375 miles between them. Motorist B travels at an average rate one-third slower than Motorist A travels. If A''s rate = 3 miles per hour, then B''s rate = 3 - (1/3)3 = 3-1 = 2 miles per hour. Implication: Of every 5 miles ...”
March 2, 2018
GMATGuruNY posted a reply to Ahmed earns $7 an hour for the first 40 hours of work in... in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represent the total number of hours. When the correct answer is plugged in, the total earned = $710. B: 90 hours, implying 80 hours of regular $7 pay and 10 hours of $10 overtime pay Total earned= (80*7) + (10*10) = 660. Since the total ...”
March 2, 2018
GMATGuruNY posted a reply to What is the value of x in the Data Sufficiency forum
“Statement 1: x³ + x² - 6x = 0 x(x² + x - 6) = 0 x(x+3)(x-2) = 0. Options for x: 0, -3, 2. Since x can be different values, INSUFFICIENT. Statement 2: 0 = x³ + 5x² - 14x 0 = x(x² + 5x - 14) 0 = x(x+7)(x-2) Options for x: 0, -7, 2. Since x can be different values, INSUFFICIENT. ...”
March 2, 2018
GMATGuruNY posted a reply to John would have reduced the time it took him to drive in the Problem Solving forum
“To reduce the time by 1/3 = to take 2/3 his actual time. Time and rate have a RECIPROCAL RELATIONSHIP. To take 2/3 his actual time, John must travel at 3/2 his actual speed. Since 3/2 his actual speed increases the speed by 15 miles per hour, we get: (3/2)s = s + 15 3s = 2s + 30 s = 30. The ...”
March 2, 2018
GMATGuruNY posted a reply to Three machines, A, B, and C, can complete a certain in the Problem Solving forum
“Let the task = the LCM of 10, 4 and 5 = 20 units. Since A takes 10 hours to complete the 20-unit task, A''s rate = w/t = 20/10 = 2 units per hour. Since B takes 4 hours to complete the 20-unit task, B''s rate = w/t = 20/4 = 5 units per hour. Since C takes 5 hours to complete the 20-unit task, ...”
March 1, 2018
GMATGuruNY posted a reply to A car traveling at a certain constant speed... in the Problem Solving forum
“80 kilometers per hour = 80 kilometers in 3600 seconds. A car takes 5 seconds longer. Since 1 kilometer takes 5 seconds longer, 80 kilometers takes 400 seconds longer, implying a rate of 80 kilometers in 4000 seconds: (80 kilometers)/(4000 seconds) * (3600 seconds)/(1 hour) = 72 kph. The ...”
February 28, 2018
GMATGuruNY posted a reply to After the announcement that London would host the 2012 Olymp in the Sentence Correction forum
“If a comparison allows for more than one logical interpretation, eliminate the answer choice. B: Paris had competed with London much longer than Madrid Interpretation 1: Paris had competed with London much longer than Madrid Interpretation 2: Paris had competed with London much longer than ...”
February 27, 2018
GMATGuruNY posted a reply to There are no legal limits, as there are for cod and haddock, in the Sentence Correction forum
“B: There are no legal limits, unlike cod D: Unlike cod, there are no legal size limits In these options, cod is illogically compared to legal limits. Eliminate B and D. C: monkfish, which contributes....through overfishing Here, overfishing seems to refer to monkish, implying that MONKFISH is ...”
February 27, 2018
GMATGuruNY posted a reply to Bert left the house with N dollars. He spent 1/4 of this... in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the total amount of money. When the correct answer is plugged in, the amount left in Bert''s pocket = 10. B: 44 Amount spent at the hardware store = (1/4)(44) = 11. Amount spent at the dry cleaners = 7. Remaining amount = 44-11-7 = 26. Since 1/2 of ...”
February 26, 2018
GMATGuruNY posted a reply to A physics class has majors and non-majors in a ratio of... in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which present the total number of people in the class. Let P = physics majors and N = non-physics majors. When the correct answer is plugged in, adding 2 physics majors will yield the following ratio: (New P)/N = 2/4 = 1/2. B: total = 28 In this case: Since P:N = ...”
February 26, 2018
GMATGuruNY posted a reply to Alice's take-home pay last year was the same each month... 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 amount not saved each month, the amount not saved each month = 12/3 = $4. Thus, the total monthly pay = (amount saved each month) + (amount not ...”
February 26, 2018
GMATGuruNY posted a reply to Traffic safety in the Sentence Correction forum
“Drivers will be as likely to exceed the proposed speed limit as they are exceeding the current one. Here, blue portion conveys a PROBABILITY (the likelihood that drivers will exceed the proposed speed limit), while the red portion conveys a FACT (drivers ARE EXCEEDING the current speed limit). ...”
February 26, 2018
GMATGuruNY posted a reply to If a,b,c and d are positive integers, is . . . . . in the Data Sufficiency forum
“Since the problem is constrained to POSITIVE VALUES, simplify (a/b)(c/d) > c/b: (a/b)(c/d) > c/b (a/d)(c/b) > c/b a/d > 1 a > d. Question stem, rephrased: Is a > d? Statement 1: No information about a or d. INSUFFICIENT. Statement 2: SUFFICIENT. The correct answer ...”
February 26, 2018
GMATGuruNY posted a reply to Which one of the following is the minimum value of in the Problem Solving forum
“Factor pairs of 36: 1*36 2*18 4*9 6*6 The smallest sum is yielded by the option in blue: 6+6 = 12. The correct answer is E. For any fixed product xy, the least possible value for x+y occurs when x=y. If xy = 16, where x and y are positive integers, we get the following options: x=1 ...”
February 26, 2018
February 26, 2018
GMATGuruNY posted a reply to Agela 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.”
February 26, 2018
GMATGuruNY posted a reply to Which of the following has the same value as 5^6? in the Problem Solving forum
“Since the 5⁶ = 5*5*5*5*5*5 = odd, the correct answer must also be odd and thus cannot have a units digit of 0. Eliminate A (30), B(50) and E(250). B: 25² = (5²)² = 5⁴. Eliminate B. The correct answer is D. D: 125² = (5³)² = 5⁶.”
February 26, 2018
GMATGuruNY posted a reply to A man sold an article at k percent profit after in the Problem Solving forum
“Let: L = the list price. C = the cost price. x = the difference between the two reduced prices. Discount = percentage of the LIST price. Since x increases the discount by 15% -- from k to k+15 -- x must be equal to 15% of the LIST price: x = (15/100)L. Profit = percentage of the COST ...”
February 25, 2018
GMATGuruNY posted a reply to Liz drove from point A to point B at 40km/h. On her way back in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represent the distance. Since the time difference yielded by the two speeds is an INTEGER VALUE -- one hour -- the correct answer is almost certain to be a multiple of the two speeds. Of the five answer choices, only B, D and E are divisible ...”
February 25, 2018
GMATGuruNY posted a reply to As the United States Census in the Sentence Correction forum
“A: more likely to own houses as to own apartments Here, as is unidiomatic. Correct: more likely to do X THAN to do Y Eliminate A. B: as likely to own...as it is D: more likely for college...than they are E: as likely that college...as they are In each of these options, the portion in red is ...”
February 25, 2018
GMATGuruNY posted a reply to A toy store's gross profit on a computer game was 10%... in the Problem Solving forum
“A toy store''s gross profit on a computer game was 10% of the cost of the game. The store increased the selling price of the game from $44. Since $44 yields 10% profit -- and 44 is 10% more than 40 -- the cost price of the game = 40. If the store increased the selling price of the game to $46 ...”
February 24, 2018
GMATGuruNY posted a reply to Three machines, A, B, and C, can complete a certain task in the Problem Solving forum
“Let the task = the LCM of 10, 4 and 5 = 20 units. Since A takes 10 hours to complete the 20-unit task, A''s rate = w/t = 20/10 = 2 units per hour. Since B takes 4 hours to complete the 20-unit task, B''s rate = w/t = 20/4 = 5 units per hour. Since C takes 5 hours to complete the 20-unit task, ...”
February 24, 2018
GMATGuruNY posted a reply to If m is the average (arithmetic mean) of the first 10 positi in the Problem Solving forum
“For any EVENLY SPACED SET, mean = median. The first 10 positive multiples of 5 constitute an evenly spaced set. Thus, mean = median, implying that M=m and that M-m = 0. The correct answer is B.”
February 24, 2018
GMATGuruNY posted a reply to If |x|=−x, which of the following must be true? in the Problem Solving forum
“Case 1: x=0, with the result that |x|=0 and -x=0 Eliminate C, D, and E, which are not true for x=0. Case 2: x=-1, with the result that |x|=1 and -x=1 Eliminate A, which is not true for x=-1. The correct answer is B.”
February 24, 2018
GMATGuruNY posted a reply to is an integer n even? in the Data Sufficiency forum
“Statement 1: Case 1: n=1, with the result that n(n+2) = 1*3 = 3 Since the value in red is not even, Case 1 is not viable. Case 2: n=3, with the result that n(n+2) = 3*5 = 15 Since the value in red is not even, Case 2 is not viable. Case 3: n=5, with the result that n(n+2) = 5*7 = 35 Since the ...”
February 24, 2018
GMATGuruNY posted a reply to Five drainage pipe, each draining water from a pool... in the Problem Solving forum
“Let the rate for each pipe = 1 liter per day, implying that the rate for 5 pipes = 5 liters per day. Since the pool is drained by 5 pipes in 12 days, the pool = rt = 5*12 = 60 liters. To drain the 60-liter pool in 4 days, the required rate = w/t = 60/4 = 15 liters per day. Since the rate must ...”
February 23, 2018
GMATGuruNY posted a reply to Residents of Milatia are known for their longevity. Nutritio in the Critical Reasoning forum
“Conclusion: Milatians can attribute their increased lifespans to their diets. Apply the NEGATION TEST. When the correct answer is negated, the conclusion will be invalidated. A, negated: Other aspects of the Militians’ lifestyle affect the observed trend of longevity in Milatia. This ...”
February 23, 2018
GMATGuruNY posted a reply to The Scandinavian assault on western Europe culminated in the Sentence Correction forum
“A and B: the English Kingdom, which other Scandinavian kings attempted to repeat Here, which seems to refer to the English kingdom, implying that other Scandanavian kings attempted to repeat THE ENGLISH KINGDOM -- a nonsensical meaning. Eliminate A and B. C: achievement that other Scandinavian ...”
February 23, 2018
GMATGuruNY posted a reply to Malik's recipe for 4 servings of a certain dish requires 3/2 in the Data Sufficiency forum
“3/2 cups of pasta are required for every 4 servings. Statement 1: Case 1: 8 servings made last time, 4 servings to be made next time Since 3/2 cups are required for every 4 servings, the number of cups required for the 4 cups to be made next time = 3/2. Case 2: 16 servings made last time, 8 ...”
February 23, 2018
GMATGuruNY posted a reply to Runners V, W, X, Y, and Z are competing in the Bayville loca in the Problem Solving forum
“Of the 5 positions in the race, 2 must be occupied by X-Y, in that order. From the 5 positions, the number of ways to choose 2 for X-Y = 5C2 = (5*4)/(2*1) = 10. The remaining 3 positions must be occupied by V-W-Z, in that order. Number of options for V-W-Z = 1. (They must occupy the remaining 3 ...”
February 22, 2018
GMATGuruNY posted a reply to Z is 120% of Y. X is smaller than Z by 80%. What percentage in the Problem Solving forum
“Alternate approach: X/Y = X/Z * Z/Y. Since X is 80% less than Z, X is 20% of Z: X/Z = 20/100 = 1/5. Since Z is 120% of Y, we get: Z/Y = 120/100 = 6/5. Substituting X/Z = 1/5 and Z/Y = 6/5 into the blue equation above, we get: X/Y = 1/5 * 6/5 = 6/25 = 24/100 = 24%. The correct answer ...”
February 21, 2018
GMATGuruNY posted a reply to What is the probability of rolling two fair dice and in the Problem Solving forum
“P(at least 1 even number) = 1 - P(2 odd numbers). Of the 6 numbers on a die, 1/2 are odd, 1/2 are even. Thus: P(2 odd numbers) = 1/2 * 1/2 = 1/4. P(at least 1 even number) = 1 - 1/4 = 3/4. The correct answer is B.”
February 21, 2018
GMATGuruNY posted a reply to A certain gallery is hanging a series of 7 paintings in the Problem Solving forum
“Number of options for the 2nd painting = 2. (Either of the 2 panel paintings.) Number of options for the 6th painting = 1. (Must be the 1 remaining panel painting.) Number of ways to arrange the remaining 5 paintings = 5! = 120. To combine the options above, we multiply: 2*1*120 = 240. The ...”
February 21, 2018
GMATGuruNY posted a reply to Tough Rate problem in the Data Sufficiency forum
“Statement 1: Each person in line has at least one present to be wrapped by one of the six clerks at the counter. Since there are 6 clerks -- and each wraps between 20 and 30 presents per hour -- the total number of presents that can be wrapped in one hour is between 120 and 180. Since each of the ...”
February 21, 2018
GMATGuruNY posted a reply to X takes 10 days to complete a task. Y takes half that... in the Problem Solving forum
“Let the task = 100 units. Since Y''s time is 1/2 X''s time -- and X''s time is 10 days -- Y''s time to complete the 100-unit task is 5 days. Thus, Y''s rate = w/t = 100/5 = 20 units per day. Since X produces 40% of the 100 units -- for a total of 40 units -- Y produces the remaining 60 units. ...”
February 20, 2018
GMATGuruNY posted a reply to If x and y are positive numbers and z = xy^2, a 50 percent.. in the Problem Solving forum
“Since x increases by 50% = 1/2, plug in an EVEN NUMBER for x: x=4. Since y decreases by 20% = 1/5, plug in a MULTIPLE OF 5 for y: y=5. Original z: z = xy² = (4)(5²) = 4*25 = 100. New z: x increased by 1/2 = 4 + (1/2)(4) = 4 + 2 = 6. y decreased by 1/5 = 5 - (1/5)(5) = 5 - 1 = 4. z = ...”
February 20, 2018
GMATGuruNY posted a reply to OG Resin is a plant secretion that hardens in the Reading Comprehension forum
“From the passage: Antiherbivore chemistry (plants'' chemical defenses against attack by herbivores such as insects). Resin...might induce the insects to feed on those plants. The portions above support A: Changes in a plant''s antiherbivore chemistry may affect insect feeding behavior. The ...”
February 20, 2018
GMATGuruNY posted a reply to A certain car traveled twice as many miles in the Problem Solving forum
“Let B to C = 18 miles. Since the rate from B to C is 18 miles per gallon, the amount of gas used from B to C = d/r = 18/18 = 1 gallon. Since the distance from A to B is twice the distance from B to C, A to B = 2*18 = 36 miles. Since the rate from A to B is 12 miles per gallon. the amount of gas ...”
February 20, 2018
GMATGuruNY posted a reply to Is the value of a^2 - b^2 in the Data Sufficiency forum
“a²-b² > (3a+3b)(2a-2b) a²-b² > 6a² - 6ab + 6ab - 6b² a²-b² > 6a² - 6b² 5b² > 5a² b² > a². Question stem, rephrased: Is b² > a²? Statement 1: Case 1: b=0, a=1 In this case, b² < a², so the answer to the question stem is NO. Case 2: b=-1, a=0 In ...”
February 20, 2018
GMATGuruNY posted a reply to Marcia took a trip consisting of three segments at three... in the Problem Solving forum
“Let v = 1 mph and D = 6 miles. Time to travel 5D miles at a speed of 2v mph = d/r = (5*6)/(2*1) = 15 hours. Time to travel 4D miles at a speed of 3v mph = d/r = (4*6)/(3*1) = 8 hours. Time to travel D miles at a speed of 6v mph = d/r = 6/(6*1) = 1 hour. Total time = 15+8+1 = 24 hours. ...”
February 19, 2018
GMATGuruNY posted a reply to Ann, Mark, Dave and Paula line up at a ticket window in the Problem Solving forum
“Number of options for the third position = 1. (Must be Dave.) Number of ways to arrange the remaining 3 people = 3!. To combine the options above, we multiply: 1*3! = 6. The correct answer is D. Most of the answer choices are quite small, implying that we can simply list all of the ...”
February 18, 2018
GMATGuruNY posted a reply to Audrey 4 hours to complete a certain job. Ferris can do... in the Problem Solving forum
“Let the job = the LCM of the 3 times = 12 units. Since Audrey''s time alone = 4 hours, Audrey''s rate = w/t = 12/4 = 3 units per hour. Since Ferris''s time alone = 3 hours, Ferris''s rate = w/t = 12/3 = 4 units per hour. Since Audrey works for the entire 2 hours, the work produced by Audrey = ...”
February 18, 2018
GMATGuruNY posted a reply to Salad dressing A is made up of 30% vinegar and 70% oil... in the Problem Solving forum
“Vinegar in A = 30%. Vinegar in B = 10%. Vinegar in the MIXTURE of A and B = 15%. To determine the ratio of A to B, use ALLIGATION -- a very efficient way to handle mixture problems. Step 1: Plot the 3 percentages on a number line, with the percentages for A and B (30% and 10%) on the ends ...”
February 18, 2018
GMATGuruNY posted a reply to At a circular table for eight will sit two children, their.. in the Problem Solving forum
“To count circular permutations: 1. Place one person at the table. 2. Count the number of ways to arrange the REMAINING people. After one of the two children has been placed at the table: Number of options for the other child = 2. (To the left or right of the first child.) Number of ...”
February 18, 2018
GMATGuruNY posted a reply to If a, b, and c are positive in the Data Sufficiency forum
“Statement 1: a/c > 1 a > c. Since b is positive, b > 0. Adding together a > c and b > 0, we get: a+b > c+0 a+b > c. Thus, the answer to the question stem is YES. SUFFICIENT. Statement 2: Since a > 0, we can divide both sides by a to yield the following: b > ...”
February 18, 2018
GMATGuruNY posted a reply to N and M are each 3-digit integers in the Problem Solving forum
“To MINIMIZE N-M: The difference between the HUNDREDS digits must be 1. The TENS digit of N must be as SMALL as possible (1) and the tens digit of M must be as GREAT as possible (8). Thus, there are only two cases to consider: Case 1: N = 31X and M = 28X. Case 2: N = 71X and M = 68X. ...”
February 18, 2018
GMATGuruNY posted a reply to In how many ways can the letters of word "EDUCATION&quo in the Problem Solving forum
“Number of ways to arrange the 5 vowels E, A, U, I, and O = 5!. Number of ways to arrange the 4 consonants D, C, T and N = 4!. To combine the options above, we multiply: 5!4!. Since VOWELS-CONSONANTS and CONSONANTS-VOWELS both constitute viable arrangements, the result above must be multiplied by ...”
February 18, 2018
GMATGuruNY posted a reply to For an odd integer n, the function f(n) is defined as the pr in the Problem Solving forum
“Since the difference between them is 1, f(71) and f(71)-1 are consecutive integers. Consecutive integers are COPRIMES: they share no factors other than 1. Let''s examine why: If x is a multiple of 2, then the next smallest multiple of 2 is x-2. If x is a multiple of 3, then the next ...”
February 17, 2018
GMATGuruNY posted a reply to In a certain housing development, each garden has... in the Problem Solving forum
“Each garden has the shape of a rectangle whose width is 2/3 its length. The perimeter of the smallest garden is 30 feet. Thus: W = (2/3)L 2(L + W) = 30, implying that L+W = 15. Substituting W = (2/3)L into L+W = 15, we get: L + (2/3)L = 15 3L + 2L = 45 5L = 45 L = 9. The length of the ...”
February 17, 2018
GMATGuruNY posted a reply to The price of each hair clip in the Problem Solving forum
“The problem above is the same as PS71 in the OG18. I posted three different approaches here: https://www.beatthegmat.com/algebra-statistics-t287565.html”
February 17, 2018
GMATGuruNY posted a reply to A car traveled 75% of the way from town A to town B... in the Problem Solving forum
“Since 75% = 3/4, let the total distance = 4 miles. A car traveled 75% of the way from town A to town B by traveling at T hours at an average speed of V mph. 3/4 of 4 miles = 3 miles. Let V = 3 mph and T = 1 hour, with the result that rt = 3*1 = 3 miles. The car travels at an average speed ...”
February 17, 2018
GMATGuruNY posted a reply to If k > 1, which of the following must be equal to... in the Problem Solving forum
“√2 ≈ 1.4. √3 ≈ 1.7. Let k=2. Plugging k=2 into the given expression, we get: 2/(√3 + √1) ≈ 2/(1.7 + 1) = 2/(2.7) = 20/27 ≈ 20/28 = 5/7. Now plug k=2 into the answer choices to see which yields a value close to 5/7. A quick scan reveals the following: The results from A, B, ...”
February 16, 2018
GMATGuruNY posted a reply to Captain Matthew Webb in the Sentence Correction forum
“In B, were (plural) does not agree with swimming (singular). Eliminate B. The past perfect (had + VERBed) serves to express a past action completed BEFORE another past event. C: eight years later...he had cost Here, the usage of had cost (past perfect) implies that the action in red was ...”
February 16, 2018
GMATGuruNY posted a reply to Min-Max problem in the Problem Solving forum
“Let''s say the following 32 problems are answered incorrectly: 1, 3, 4, 5, 7, 8, 10, 12, 13, 14 15, 16, 17, 19, 20, 21, 22, 24, 25, 26 27, 28, 29, 30, 33, 34, 36, 40, 41, 42 43, 44 The set in red constitutes the first 10 incorrect answers. Thus, each of these answers receives a mark of ...”
February 16, 2018
GMATGuruNY posted a reply to Despite Japan’s in the Sentence Correction forum
“In B, it lacks a clear referent. Eliminate B. C: Despite being relatively isolated, the prolonged peace Here, being relatively isolated seems to refer to the prolonged peace, implying that THE PROLONGED PEACE was being relatively isolated. This meaning is nonsensical. Eliminate C. In D, at ...”
February 16, 2018
GMATGuruNY posted a reply to A and B can complete a task in 20 days. B and C can... in the Problem Solving forum
“Let the task = the LCM of 20, 30, and 40 = 120 units. Since A+B take 20 days to complete the task, the rate for A+B = 120/20 = 6 units per day. Since B+C take 30 days to complete the task, the rate for B+C = 120/30 = 4 units per day. Since A+C take 40 days to complete the task, the rate for A+C ...”
February 15, 2018
GMATGuruNY posted a reply to Papayaya in the Problem Solving forum
“Recipe: Soda = 4/7. Lemon = 1/3. Remainder = 1/2 sugar, 1/2 puree. Let the total recipe = the LCM of 7, 3 and 2 = 42. Original values: Soda = (4/7)(42) = 24. Lemon = (1/3)(42) = 14. Remainder = 42-24-14 = 4, implying that sugar = 2 and that puree = 2. After the malfunction: Lemon ...”
February 15, 2018
GMATGuruNY posted a reply to Trains A and B start simultaneously from stations 300... in the Problem Solving forum
“Since A and B travel toward each other, they WORK TOGETHER to cover the 300 miles between them. When elements work together, ADD THEIR RATES. The combined rate for A and B = 50+40 = 90 miles per hour. Of every 90 miles traveled by A and B working together, 50 miles are traveled by A. ...”
February 15, 2018
GMATGuruNY posted a reply to In a survey of students, each student selected from a... in the Problem Solving forum
“Since the each of the 12 songs is selected 4 times, the total number of song selections = 12*4 = 48. Since each student makes 2 selections, we get: Number of students = (total selections)/(selections per student) = 48/2 = 24. The correct answer is D.”
February 15, 2018
GMATGuruNY posted a reply to In a certain quiz that consists of 10 questions, each questi in the Problem Solving forum
“Since each question is worth 4 more points than the preceding question, the point values constitute an EVENLY SPACED SET. For any evenly spaced set: Average = Median. Since the 10 point values sum to 360, we get: Average = median = 360/10 = 36. We can PLUG IN THE ANSWERS, which represent ...”
February 15, 2018
GMATGuruNY posted a reply to Pipe P can drain the liquid from a tank in 3/4 the time in the Problem Solving forum
“(P''s time)/(Q''s time) = 3/4 = 6/8. (P''s time)/(R''s time) = 2/3 = 6/9. Let: P''s time = 6 hours. Q''s time = 8 hours. R''s time = 9 hours. Let the tank = the LCM of the 3 times = 72 liters. Since P takes 6 hours to drain the 72-liter tank, P''s rate = w/t = 72/6 = 12 liters per hour. ...”
February 15, 2018
GMATGuruNY posted a reply to Is the average of ten integers greater than 10? in the Data Sufficiency forum
“If the average of 10 integers = 10, then the SUM of the 10 integers = (number of integers)(average of the integers) = 10*10 = 100. Implication: For the average of the 10 integers to be GREATER THAN 10, the sum of the 10 integers must be GREATER THAN 100. Question stem, rephrased: Is the sum of ...”
February 15, 2018
GMATGuruNY posted a reply to Min-Max problem in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the least number of questions that must be answered correctly to yield a nonnegative score. Since we need the least number of questions, start with the smallest answer choice. E: 17 Points earned for 17 correct answers = 17*1 = 17. Total number of ...”
February 14, 2018
GMATGuruNY posted a reply to Sentence Correction in the Sentence Correction forum
“A COMPOUND subject is composed of two nouns connected by and: X and Y. Generally, a compound subject requires a PLURAL verb. A, B and C: Pollution and degradation...is a matter Here, is (singular) does not agree with pollution and degradation (plural). Eliminate A, B and C. Generally, ...”
February 14, 2018
GMATGuruNY posted a reply to Which of the following inequalities in the Problem Solving forum
“|x-y| = the DISTANCE between x and y The midpoint between -2 and 4 = the average of -2 and 4 = (-2+4)/2 = 1. -2 < x < 4 implies that x can be any value between -2 (3 places to the LEFT of 1) and 4 (3 places to the RIGHT of 1). In other words: the distance between x and 1 must be less ...”
February 14, 2018
GMATGuruNY posted a reply to When a person aged 39 is added to a group of n people in the Problem Solving forum
“I received a PM requesting that I explain how the problem can be solved with alligation. Let A = the one added person. Case 1: Average age for the first N people = x. Average age for A = 39. Average for the MIXTURE of all the people = x+2. Step 1: Plot the 3 averages on a number line, with ...”
February 13, 2018
GMATGuruNY posted a reply to For Ralph Waldo Emerson, transcendentalism was his professed in the Sentence Correction forum
“to launch X = to initiate X. B: The contemporary American environmental movement launched itself Conveyed meaning: The movement INITIATED ITSELF. This meaning is nonsensical. Eliminate B. D: The contemporary American environmental movement launched Rachel Carson’s "Silent ...”
February 13, 2018
GMATGuruNY posted a reply to People who have spent a lot of time in contact with animals in the Critical Reasoning forum
“The key word in the argument is current: the survey included not ALL zoo employees, past and present, but only CURRENT zoo employees. One way to strengthen the argument would be to show that -- because the survey included only current employees -- the percentage with allergies was UNDERREPORTED. ...”
February 13, 2018
GMATGuruNY posted a reply to Beth and Jim each received a salary increase. If Jim's in the Data Sufficiency forum
“Let the percent increase = 10%. Statement 1: No information about Karen''s salary. INSUFFICIENT. Statement 2: Case 1: Beth''s salary = $500, Jim''s salary = (4/5)(500) = $400 Dollar increase for Beth = 10% of 500 = 50. Dollar increase for Jim = 10% of 400 = 40. In this case, Beth''s ...”
February 13, 2018
GMATGuruNY posted a reply to For integers a, b, and c, if ab = bc in the Problem Solving forum
“ab = bc ab - bc = 0 b(a-c) = 0. Implication: Either b=0 or a-c=0. Given this constraint, prove that four of the answer choices DON''T have to be true. Case 1: b=0, a=2, c=1 In this case, A, C, D and E are not true. Eliminate A, C, D and E. The correct answer is B.”
February 13, 2018
GMATGuruNY posted a reply to When a person aged 39 is added to a group of n people in the Problem Solving forum
“Alternate approach: Let s = the original sum. New sum when a person of 39 years is added = s+39. New sum when a person of 15 years is added = s+15. Difference between the two new sums = (s+39) - (s+15) = 24. We can PLUG IN THE ANSWERS, which represent the current number of people. Let a = ...”
February 13, 2018
GMATGuruNY posted a reply to Sentence Correction in the Sentence Correction forum
“like serves to compare one NOUN to another NOUN and means similar to. X is like Y = X is similar to Y. A: Like the veneration, George Washington This comparison is illogical, implying that GEORGE WASHINGTON is similar to THE VENERATION. Eliminate A. As leader of the student council, Mary ...”
February 12, 2018
GMATGuruNY posted a reply to If n is a positive integer and 10^n is a factor of m in the Data Sufficiency forum
“Since the statements refer to 40!, determine options for n if 10^n is a factor of 40!. Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of 40! will enable 10^n to divide into 40!. The prime-factorization of 40! includes FAR MORE 2''S than 5''s. Thus, the number ...”
February 12, 2018
GMATGuruNY posted a reply to If n = p/q, where p and q are nonzero integers in the Data Sufficiency forum
“Statement 1: Either n is an integer or n is an irrational number such as √2. An irrational number cannot be written as integer/integer. Since n = p/q = integer/integer, n cannot be an irrational number such as √2. Thus, n must be an integer, and the answer to the question stem is YES. ...”
February 12, 2018
GMATGuruNY posted a reply to If ab=ac is b=2? in the Data Sufficiency forum
“ab = ac ab - ac = 0 a(b-c) = 0. The resulting equation is valid only if a=0 or b=c. Implication: If a=0, then b can be ANY VALUE. If a≠0, then b=c. Statement 1: Case 1: a=0, b=2, c=1 In this case, the answer to the question stem is YES. Case 2: a=0, b=1, c=1 In this case, the answer ...”
February 12, 2018
GMATGuruNY posted a reply to The 8 spokes in the Problem Solving forum
“Since the difference between one central angle and the next is constant, the central angles constitute an EVENLY SPACED SET. For any evenly spaced set: Average = (biggest + smallest)/2. Since there are 8 spokes, the number of central angles = 8. Since the 8 central angles form a 360° circle, ...”
February 12, 2018
GMATGuruNY posted a reply to A certain company assign 5 rooms to each of its 5 employees in the Problem Solving forum
“The problem above is the same as the following: If the correct ordering for five letters is ABCDE, how many ways can the letters be arranged so that no letter is in the correct position? A DERANGEMENT is a permutation in which NO element is in the correct position. Given n elements (where ...”
February 11, 2018
GMATGuruNY posted a reply to Triangle ABC has a perimeter of 18. Which of the following in the Problem Solving forum
“Given a FIXED PERIMETER for a triangle, the greatest possible are will be yielded if the triangle is EQUILATERAL. The area of an equilateral triangle = (s²/4)√3. √3 ≈ 1.7. If a triangle with a fixed perimeter of 12 is equilateral -- implying that each side has a length of 4 -- we get: ...”
February 11, 2018
GMATGuruNY posted a reply to If xy > 0, is xyz < 0? in the Data Sufficiency forum
“Since xy>0, x and y have the SAME SIGN. Statement 1 implies that x and z have the same sign. Statement 2 implies that y and z have the same sign. Implication: When the two statements are combined, all three variables -- x, y and z -- must have the same sign. Statements combined: Case 1: ...”
February 11, 2018
GMATGuruNY posted a reply to Jennifer has 60 dollars more than Brian. If she were to in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent Jennifer''s amount. When the correct answer is plugged in, Brian''s new amount will be 75% of Jennifer''s new amount, with the result that his new amount will be 25% LESS than her new amount. Since the problem involves PERCENTS, start with J=100. B: ...”
February 11, 2018
GMATGuruNY posted a reply to Gall’s hypothesis in the Sentence Correction forum
“A: Gall''s hypothesis of there being different mental functions B: Gall''s hypothesis of different mental functions Conveyed meaning: Gall hypothesizes the EXISTENCE of different mental functions. Not the intended meaning. Since it is common knowledge that the brain is capable of different ...”
February 11, 2018
GMATGuruNY posted a reply to Problem Solving in the Problem Solving forum
“Since 15% = 15/100 = 3/20, let the rectangle be a SQUARE with a side of 20. Original area = s² = 20² = 400. After each side is increased by 15% to 23, the new area = s² = 23² = 529. Percent increase from 400 to 529 = (Difference/Smaller) * 100 = (129/400) * 100 = 129/4 = 32.25. The correct ...”
February 11, 2018
GMATGuruNY posted a reply to Four friends, Charles, Mike, Brian, and John, went on a... in the Problem Solving forum
“Mike spent $400 more than Brian did. Let B=1000, implying that M = 1000+400 = 1400. Charles spent $400 more than Mike did. Since M=1400, C = 1400+400 = 1800. John spent $1200 less than Charles did. Since C=1800, J = 1800-1200 = 600. How many more dollars did Brian spend than John did? ...”
February 10, 2018
GMATGuruNY posted a reply to Problem Solving in the Problem Solving forum
“Check here: https://www.beatthegmat.com/bob-bikes-to-school-t300244.html”
February 10, 2018
GMATGuruNY posted a reply to Sets X and Y consist solely of positive integers. Each set in the Data Sufficiency forum
“Statement 1: We don''t know which set has the greater range. More importantly, we know nothing about the how the values in each set are dispersed from the mean. Thus, we cannot determine which set has the greater SD. INSUFFICIENT. Statement 2: X = (1, 2), Y = (1, 4) X = (1, 3, 5), Y = (1, ...”
February 10, 2018
GMATGuruNY posted a reply to If a and b are integers in the Data Sufficiency forum
“Statement 1: Case 1: a=1 and b=1, with the result that a+b = 1+1 = 2 In this case, ab/4 = (1*1)/4 = 1/4, so the answer to the question stem is NO. Case 2: a=2 and b=2, with the result that a+b = 2+2 = 4 In this case, ab/4 = (2*2)/4 = 4/4 = 1, so the answer to the question stem is YES. ...”
February 10, 2018
GMATGuruNY posted a reply to If Jan spent 40% in the Problem Solving forum
“Let Jan''s income = 100. Since 40% is spend on housing, Jan''s housing payment = 40% of 100 = 40. Since the car payment is 20% less than the housing payment, Jan''s car payment = 40 - (20% of 40) = 40 - 8 = 32. What percent of her monthly income did she have left after making both her housing ...”
February 10, 2018
GMATGuruNY posted a reply to Problem Solving in the Problem Solving forum
“Since 40% - 33% = 7%, the taxpayer will save 7% of annual income: (7/100)(45000) = 3150. The correct answer is C.”
February 10, 2018
GMATGuruNY posted a reply to Ali and Moe can do a certain job together in 4 hours... in the Problem Solving forum
“Since Ali''s rate is 5 time''s Moe''s rate, let Moe''s rate = 1 unit per hour and Ali''s rate = 5 units per hour, for a combined rate of 6 units per hour. Working together at a rate of 6 units per hour, they complete the job in 4 hours, implying that the job = rt = 6*4 = 24 units. Since Ali''s ...”
February 9, 2018
GMATGuruNY posted a reply to Walking at 60% of his usual speed a man takes... in the Problem Solving forum
“Time and rate have a RECIPROCAL RELATIONSHIP: If Amy''s rate is 2 times Bob''s rate, then Amy''s time is 1/2 Bob''s time. If Amy''s rate is 3 times Bob''s rate, then Amy''s time is 1/3 Bob''s time. Since the man is walking at 60% = 3/5 of his normal speed, he will take 5/3 of his normal ...”
February 9, 2018
GMATGuruNY posted a reply to Although all the events in the Sentence Correction forum
“Non-underlined portion: the few events that were The words in brackets are omitted but implied. Conveyed meaning: SOME of the events were carried live. A and B: all of events...were not carried live Conveyed meaning: No events were carried live. This meaning contradicts the statement in ...”
February 9, 2018
GMATGuruNY posted a reply to Because it was long thought in the Critical Reasoning forum
“Premise: A substantial portion of the viewing public tuned into the advertisement. Conclusion: Many more people are interested in watching lengthy televised political messages than was previously thought. Apply the NEGATION TEST. When the correct answer is negated, the conclusion will be ...”
February 9, 2018
GMATGuruNY posted a reply to David covers a total of 240 miles journey, of which in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the greater of the two speeds. When the correct answer is plugged in, the time difference for the two speeds will be 1 hour. Since the time difference is an INTEGER VALUE, it is almost guaranteed that the two speeds will divide evenly into the 120-mile ...”
February 8, 2018
GMATGuruNY posted a reply to Speed in the Problem Solving forum
“The value in red is incorrect. x = Mary''s head start. When Dan starts to run, he is x meters behind Mary. As Dan races to close the x-meter gap between him and Mary, Mary CONTINUES TO MOVE FORWARD. Implication: To close the x-meter gap and overtake Mary in 10 seconds, Dan must travel in 10 ...”
February 8, 2018
GMATGuruNY posted a reply to Barbara walked up and down a 25 meter long in the Problem Solving forum
“Since the distance traveled at each speed is THE SAME, we can determine the average speed by plugging in ANY VALUE for the distance. Let the distance in each direction = 4 meters. When Barbara travels the 4-meter corridor at a rate of 4 meters per second, her time = d/r = 4/4 = 1 second. When ...”
February 8, 2018
GMATGuruNY posted a reply to Speed in the Problem Solving forum
“Alternate approach: Time and rate have a RECIPROCAL RELATIONSHIP: If Amy''s rate is 2 times Bob''s rate, then Amy''s time is 1/2 Bob''s time. If Amy''s rate is 3 times Bob''s rate, then Amy''s time is 1/3 Bob''s time. Since the rate ratio for Dan and Mary = 5:4, Dan''s rate is 5/4 Mary''s ...”
February 8, 2018
GMATGuruNY posted a reply to GMAT Prep QP1 : In the English-Speaking world Anton in the Sentence Correction forum
“The COMPARATIVE form of an adjective serves to compare two things: Adam is TALLER than Bob. Chocolate is MORE POPULAR than vanilla. The SUPERLATIVE form of an adjective serves to indicate the MOST EXTREME member of a group: Adam is the TALLEST member of the team. Chocolate is the MOST POPULAR ...”
February 8, 2018
GMATGuruNY posted a reply to Mark biked in the Data Sufficiency forum
“Let t = the number of hours. Statement 1: Since the distance can be any positive value, the value of t cannot be determined. INSUFFICIENT. Statement 2: Case 1: r = 72 blocks per hour, implying that d = 72t If the rate increases by 8 blocks per hour to 80 blocks per hour, Mark takes 1 fewer ...”
February 8, 2018
GMATGuruNY posted a reply to Speed in the Problem Solving forum
“Your understanding seems correct. To give a person a head start = to allow that person to start EARLY. In my solution, Dan takes 10 seconds to catch-up to Mary, with the result that Dan overtakes Mary at the 50-meter mark. Since Mary''s rate = 4 meters per second, the time for Mary to reach the ...”
February 7, 2018
GMATGuruNY posted a reply to Speed in the Problem Solving forum
“In my post above, Dan takes 10 seconds to catch up to Mary. Since Dan''s rate = 5 meters per second, the distance traveled by Dan in 10 seconds = rt = 5*10 = 50 meters. Implication: Dan overtakes Mary at the 50-meter mark. Put another way: When Dan overtakes Mary, BOTH runners have traveled 50 ...”
February 7, 2018
GMATGuruNY posted a reply to Speed in the Problem Solving forum
“Let Dan''s rate = 5 meters per second and Mary''s rate = 4 meters per second. Since Mary finishes the race in 60 seconds, the total distance = rt = 4*60 = 240 meters. Mary is given a head start of x meters. Since Dan takes 20 SECONDS to catch up to Mary by x meters and then travel ahead another ...”
February 7, 2018
GMATGuruNY posted a reply to A carpenter worked alone for 1 day on a job that... in the Problem Solving forum
“Let F = the first carpenter and S = the second carpenter. Since F works for 1 day and would need 6 more days to complete the job, F''s time for the whole job = 7 days. Let the job = the LCM of 7 days and 4 days = 28 units. Since F takes 7 days to complete the 28-unit job, F''s rate = w/t = ...”
February 7, 2018
GMATGuruNY posted a reply to The population of a certain country X in the Problem Solving forum
“Density of X = (population)/(square kilometers) = (120,108,000)/(2,998,000) ≈ (120,000,000)/(3,000,000) = 120/3 = 40. Density of Y = (population)/(square kilometers) = (200,323,00)/(7,899,000) ≈ (200,000,000)/(8,000,000) = 200/8 = 25. The population density of country X is approximately ...”
February 7, 2018
GMATGuruNY posted a reply to If P and Q in the Data Sufficiency forum
“Statement 1: Case 1: larger circle = 50π, smaller circle = 40π Case 2: larger circle = 60π, smaller circle = 30π Since the larger circle can have different areas, its radius cannot be determined. INSUFFICIENT. Statement 2: Here, the radius of the larger circle can be any positive value. ...”
February 7, 2018
GMATGuruNY posted a reply to How many values of x satisfy the equation ||x-7|-9|=11? in the Problem Solving forum
“Case 1: |x-7| - 9 = 11 |x-7| = 20 If x-7 = 20, then x=27. If x-7 = -20, then x = -13. Case 2: |x-7| - 9 = -11 |x-7| = -2 Since an absolute value cannot be equal to a negative, Case 2 is not possible. Only the values in blue are viable solutions. The correct answer is B.”
February 7, 2018
GMATGuruNY posted a reply to Is it true that x > 0? in the Data Sufficiency forum
“Statement 1: x² - 2x = 0 x(x-2) = 0. The resulting equation is satisfied by x=0 (in which case the answer to the question stem is NO) or by x=2 (in which case the answer to the question stem is YES). INSUFFICIENT. Statement 2: x³ - 3x = 0 x(x² - 3) = 0. The resulting equation is ...”
February 6, 2018
GMATGuruNY posted a reply to Which of the following in the Problem Solving forum
“RULE: If x+y = k, then the greatest possible value for xy occurs when x=y. For example: If x+y = 10, then the greatest possible value for xy occurs when x=y=5: If x=1 and y=9, then xy = 9. If x=2 and y=8, then xy = 16. If x=3 and y=7, then xy = 21. If x=4 and y=6, then xy = 24. If x=5 and ...”
February 6, 2018
GMATGuruNY posted a reply to If (1+x)y=y, which of the following must be true? in the Problem Solving forum
“Once you have determined that xy=0, consider each solution separately. One solution for xy=0 is x=0. A: x=-1 or y=0 If x=0, then it does not have to be true that x=-1 or y=0. Eliminate A. C: x=1 or y=1 If x=0, then it does not have to be true that x=1 or y=1. Eliminate C. D: x=-1 or ...”
February 6, 2018
GMATGuruNY posted a reply to The bolas spider, in its sticky globules, hanging from silke in the Sentence Correction forum
“Let ⬇︎ represent the silken threads. A: The bolas spider...hanging from silken threads dangled from its front legs B and D: Hanging from silken threads dangled from its front legs, the bolas spider E: The bolas spider...hangs from silken threads dangled from its front legs According to ...”
February 5, 2018
GMATGuruNY posted a reply to Last year, Company X paid out a total of $1,05,000... in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the smallest possible salary. To MINIMIZE the smallest salary, we must MAXIMIZE the other 20 salaries. Thus, each of the other 20 salaries must be the maximum allowed value: 20% greater than the smallest salary. Since the sum of the salaries is ...”
February 5, 2018
GMATGuruNY posted a reply to Two teams are distributing information booklets. Team A... in the Problem Solving forum
“To determine what COULD be the total number of booklets, test the SMALLEST POSSIBLE CASE. Since 60% = 3/5, plug in the SMALLEST POSSIBLE VALUE -- 5 -- for the unknowns attributed to team B. Team B: Let the number of boxes = 5. Let the booklets per box = 5. Total booklets = 5*5 = 25. ...”
February 5, 2018
GMATGuruNY posted a reply to At a certain university in the Problem Solving forum
“Let a = the number of advisers. Since there are 3500 residents -- and the ratio of advisers to residents must be at least 7/200 -- we get: a/3500 ≥ 7/200 200a ≥ 3500*7 2a ≥ 35*7 2a ≥ 245 a ≥ 122.5. Since the value of a must be an INTEGER, the least possible value for a is 123. ...”
February 5, 2018
GMATGuruNY posted a reply to There are 5 couples. If they sit on 10 chairs around a round in the Problem Solving forum
“For circular arrangements: 1. Place an element at the table. 2. Count the number of ways to arrange the REMAINING elements. Once a couple has been placed at the table: Number of ways to arrange the remaining 4 couples = 4! = 24. Since the members of each couple can be arranged 2 ways -- and ...”
February 5, 2018
GMATGuruNY posted a reply to At the beginning of 2010, 60% of the population of Town X li in the Problem Solving forum
“Alternate approach: Let the population in the south = 600 and the population in the north = 400, for a total of 1000 people. Total growth for entire population of 1000 people = 5.5% of 1000 = 55. Growth for the 600 people in the south = 4.5% of 600 = 27. Growth for the 400 people in the north ...”
February 4, 2018
GMATGuruNY posted a reply to During the Great Depression in the Sentence Correction forum
“to fall down = to collapse from an upright position onto the floor. A: Output fell...from its peak...down to its nadir Here, the usage of fell down implies that the output was in an upright position and collapsed onto the floor. Not the intended meaning. Eliminate A.”
February 4, 2018
GMATGuruNY posted a reply to A wire is cut into three equal parts. The resulting... in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the minimum length of the wire. When we plug in the correct answer, we will be able to divide the wire first into 3 equal parts and then into 4, 6, and 8 equal parts. Since the question stem asks for the MINIMUM length, start with the smallest answer ...”
February 4, 2018
GMATGuruNY posted a reply to What percent in the Data Sufficiency forum
“Statements combined: Case 1: 20 women and 80 men, for a total of 100 people Since 5% of the women have red hair, the number of women with red hair = (5/100)(20) = 1. Since 10% of the men have red hair, the number of men with red hair = (10/100)(80) = 8. What percent of a group of people are ...”
February 4, 2018
GMATGuruNY posted a reply to If 7x – y in the Problem Solving forum
“Adding together the two equations, we get: (7x-y) + (7y-x) = 23 + 31 6x + 6y = 54 x+y = 9. The correct answer is E.”
February 4, 2018
GMATGuruNY posted a reply to Neither of my aunts, both of whom visited Venice last spring in the Sentence Correction forum
“neither of the X''s = not ONE of the X''s. As a result, neither of the X''s is SINGULAR. In A, B and C, want (plural) does not agree with neither of my aunts (singular). Eliminate A, B and C. The present perfect (has/have + VERBed) cannot serve to express an action performed at a particular ...”
February 3, 2018
GMATGuruNY posted a reply to Machine M, N, O working simultaneously. Machine M can... in the Problem Solving forum
“Let O''s time to produce x units = 12 hours. Since N''s time is 2/3 of O''s time, N''s time to produce x units = (2/3)(12) = 8 hours. Since M''s time is 3/4 of N''s time, M''s time to produce x units = (3/4)(8) = 6 hours. Let x = 24 units. Since O takes 12 hours to produce 24 units, O''s rate ...”
February 3, 2018
GMATGuruNY posted a reply to If −1/3 ≤ x ≤−1/5 and -1/2 ≤ y ≤ −1/4 in the Problem Solving forum
“Calculate using EVERY COMBINATION OF ENDPOINTS: (-1/3)²(-1/2) = -1/18. (-1/3)²(-1/4) = -1/36. (-1/5)²(-1/2) = -1/50. (-1/5)²(-1/4) = -1/100. The results above indicate the following: The smallest possible product is -1/18. The greatest possible product is -1/100. Thus: -1/18 ≤ x²y ...”
February 3, 2018
GMATGuruNY posted a reply to During a certain in the Problem Solving forum
“We can also calculate step-by step. Since the rate is 5 gallons per 2 hours, and the total gas used = 3.75 gallons, we can set up the following proportion: (5 gallons)/(2 hours) = (3.75 gallons)/(x hours). 5x = (2)(3.75) 5x = 7.5 x = 1.5 hours. 1.5 hours = 90 minutes. Since the car ...”
February 3, 2018
GMATGuruNY posted a reply to During a certain in the Problem Solving forum
“Since 5 gallons are used every 2 hours, 2 hours is the equivalent of 5 gallons. Since there are 60 minutes in an hour, 60 minutes is the equivalent of 1 hour. Since the rate is 1 mile per minute, 1 mile is the equivalent of 1 minute. Use the ratios above to convert the amount of gas used -- ...”
February 3, 2018
GMATGuruNY posted a reply to Pat is reading a book in the Data Sufficiency forum
“Test EXTREMES. Statements combined: Case 1: The first 3 chapters have 11 pages each, the next 2 chapters have 1 page each, and the last 10 chapters have 10 pages each. In this case: Pages in the first 5 chapters = (pages in the first three 11-page chapters) + (pages in the next two 1-page ...”
February 3, 2018
GMATGuruNY posted a reply to In the diagram, what is the value of x? in the Problem Solving forum
“The GMAT does not expect knowledge of cosines. This problem can be solved using two common triangles: 45-45-90 and 30-60-90. Step 1: Divide the 30-75-75 triangle into common triangles https://preview.ibb.co/bNUzg6/30_75_75_0.png Step 2: Calculate the sides of 45-45-90 triangle ADC In a ...”
February 2, 2018
GMATGuruNY posted a reply to A test maker is to design a probability test from a list... in the Problem Solving forum
“Hard: From 7 options, the number of ways to choose 2 = 7C2 = (7*6)/(2*1) = 21. Medium: From 7 options, the number of ways to choose 2 = 7C2 = (7*6)/(2*1) = 21. Easy: From 7 options, the number of ways to choose 2 = 7C2 = (7*6)/(2*1) = 21. To combine the options for each category, we ...”
February 2, 2018
GMATGuruNY posted a reply to The useful life of a certain piece of equipment is... in the Problem Solving forum
“Original values: Let d=1 and h=2, with the result that u = 8d/h² = (8*1)/2² = 2. New values: When d is doubled to 2 and h is halved to 1, u = 8d/h² = (8*2)/1² = 16. Percent increase from 2 to 16 = Difference/Smaller * 100 = (16-2)/2 * 100 = 700. The correct answer is D.”
February 2, 2018
GMATGuruNY posted a reply to It take 6 days for 3 women and 2 men working together... in the Problem Solving forum
“We can PLUG IN THE ANSWERS. When the correct answer is plugged in, 3 men will take 5 fewer days than 9 women to complete the job. Since the time for 3 men is much less than the time for 9 women, the men must work MUCH FASTER than the women. Thus, the correct answer is probably D or E. D: 6 ...”
February 2, 2018
GMATGuruNY posted a reply to Eight friends in the Problem Solving forum
“Original cost per person = (total bill)/(number of people) = 480/8 = 60. Since the total cost is discounted by 25%, the cost per person is also discounted by 25%: 60 - (25/100)(60) = 60 - (1/4)(60) = 60 - 15 = 45. The correct answer is C.”
February 2, 2018
GMATGuruNY posted a reply to If 2^n+2^n-2=5120, then n=? in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the value of n. When the correct answer is plugged in, the given expression will be equal to 5120. D: n=11 Plugging n=11 into the given expression, we get: 2¹¹ + 2¹¹¯² = 2¹¹ + 2⁹ = 2⁹(2² + 1) = 512(5) = 2560. Since the result is too ...”
February 2, 2018
GMATGuruNY posted a reply to Is the positive integer x divisible by 60? in the Data Sufficiency forum
“Statements combined: Case 1: x=30, with the result that x is divisible by both 6 and 10 Here, x is NOT divisible by 60, so the answer to the question stem is NO, .. Case 2: x=60, with the result that x is divisible by both 6 and 10 Here, x IS divisible by 60, so the answer to the question stem ...”
February 2, 2018