# gmatgeek2

Brent@GMATPrepNow posted a reply to Madge paid A dollars for R bananas. Dean paid B dollars for in the Data Sufficiency forum
“ Given: Madge paid A dollars for R bananas. Dean paid B dollars for S bananas. Target question: Which one of them paid a higher price-per-banana? Statement 1: B > A This tells us that Dean PAID more than Madge paid. However, we don''t know HOW MANY bananas each person bought. ...”
Today
Brent@GMATPrepNow posted a reply to Jason's salary and Karen's salary were each p percent in the Data Sufficiency forum
“Target question: What is the value of p? Given: Jason''s salary and Karen''s salary were each p percent greater in 1998 than in 1995. IMPORTANT: If my 1998 salary is p percent greater than my 1995 salary, then: 1998 salary = (1 + p/100)(1995 salary) For example, if my 1998 salary is 7 percent ...”
Today
Brent@GMATPrepNow posted a reply to If w + 2x = 150, 2w + 3y = 100, and x + 3z = 50, what is the in the Problem Solving forum
“GIVEN: w + 2x = 150 2w + 3y = 100 x + 3z = 50 If we add all 3 equations, we get: 3w + 3x + 3y + 3z = 300 Divide both sides by 3 to get: w + x + y + z = 100 Answer: D Cheers, Brent”
Today
GMATGuruNY posted a reply to Did Jeff record more sales revenue this month than Dan did? in the Data Sufficiency forum
“Statement 1: For every $100 commission that Dan earns, Jeff earns$120 in commission. Since the commission rates for Dan and Jeff are unknown, no way to determine whether Jeff recorded more sales revenue than Dan. INSUFFICIENT. Statement 2: Since Jeff''s sales and Dan''s sales can be any ...”
Yesterday
GMATGuruNY posted a reply to If sets A and B have the same number of terms, is the standa in the Data Sufficiency forum
“Standard deviation describes how much the values in a set deviate from the mean. A larger standard deviation indicates that the values are deviating more -- getting farther away from -- the mean. So the question can be rephrased: Do the values in set A deviate more from the mean than the do ...”
Yesterday
GMATGuruNY posted a reply to Is (y−10)^2>(x+10)^2? ----Veritas in the Data Sufficiency forum
“x² < y² can be rephrased as follows: |x| < |y| Thus, the question stem can be rephrased as follows: Is |x+10| < |y-10|? |a-b| = the distance between a and b |a+b| = |a-(-b)| = the distance between a and -b Thus, the question stem can be further rephrased as follows: Is the ...”
Yesterday
Brent@GMATPrepNow posted a reply to If A is the center of the circle shown above and AB = BC in the Problem Solving forum
“First recognize that all radii (indicated with BLUE lines) have equal length https://i.imgur.com/iz8ur0Z.png Since BC and CD are both equal to the radius AB, we can see that all BLUE lines have equal length https://i.imgur.com/mF0UxTp.png This means the 2 blue triangles are EQUILATERAL ...”
December 13, 2018
GMATGuruNY posted a reply to Three congruent circles overlap in such a way that each circ in the Problem Solving forum
“The statement above is incorrect. https://i.postimg.cc/jL1NMjTL/three-congruent-circles-shaded-region.png The shaded region encompassing the equilateral triangle is not a circle.”
December 13, 2018
Brent@GMATPrepNow posted a reply to If m and n are positive integers, is mn an even number? in the Data Sufficiency forum
“Some important rules: #1. ODD +/- ODD = EVEN #2. ODD +/- EVEN = ODD #3. EVEN +/- EVEN = EVEN #4. (ODD)(ODD) = ODD #5. (ODD)(EVEN) = EVEN #6. (EVEN)(EVEN) = EVEN Target question: Is mn an even number? Given: m and n are positive integers Statement 1: m/n is an even number. ...”
December 13, 2018
Brent@GMATPrepNow posted a reply to What distance did Jane travel? in the Data Sufficiency forum
“Target question: What distance did Jane travel? Statement 1: Bill traveled 40 miles in 40 minutes. No info about Jane Statement 1 is NOT SUFFICIENT Statement 2: Jane traveled at the same average rate as Bill We don''t know Bill''s speed (rate) Statement 2 is NOT SUFFICIENT ...”
December 13, 2018
GMATGuruNY posted a reply to Three congruent circles overlap in such a way that each circ in the Problem Solving forum
“Area of an equilateral triangle = (s²/4)√3. √3 ≈ 1.7. https://i.postimg.cc/1gCbnSTK/three-congruent-circles.png Each circle has a radius of 8, yielding the equilateral triangle above. Area of the equilateral triangle = (8²/4)√3 = 16√3 ≈ (16)(1.7) = 27. The three circles form ...”
December 13, 2018
Brent@GMATPrepNow posted a reply to If Mike buys a biclycle and a helmet for a total cost of in the Data Sufficiency forum
“Target question: How much does the helmet cost? Given: bicycle + helmet = $315 Statement 1: The bicycle costs twice as much as the helmet. Let x = cost of helmet So, 2x = cost of bicycle Since the total cost is$315, we can write: x + 2x = 315 Simplify: 3x = 315 Solve: x = 315/3 = ...”
December 13, 2018
Brent@GMATPrepNow posted a reply to In isosceles triangle DEF, what is the measure of angle E? in the Data Sufficiency forum
“Target question: What is the measure of ∠E? Given: Triangle DEF is an ISOSCELES triangle This tells us that there are 2 equal angles Statement 1: ∠D measures 42 degrees Here it''s hard to tell whether there''s a second 42-degree angle or whether the other two angles are different. ...”
December 12, 2018
Brent@GMATPrepNow posted a reply to Ramon wants to cut a rectangular board into identical square in the Problem Solving forum
“If we aren''t wasting any wood, the length and width must be divisible by one side of the square So, this question is a clever way of asking us what the greatest common divisor (GCD) of 18 and 30 The GCD of 18 and 30 is 6, so if we cut squares that are 6 x 6, then we won''t waste any wood. We ...”
December 12, 2018
Brent@GMATPrepNow posted a reply to How many perfect squares lie between 2^4 and 2^8, inclusive? in the Problem Solving forum
“First rewrite 2^4 and 2^8 as SQUARES of integers (aka perfect squares) 2^4 = (2²)² = 4² 2^8 = (2^4)² = 16² So, we want to find the number of perfect squares FROM 4² to 16² inclusive Let''s list them: 4², 5², 6², 7², 8², 9², 10², 11², 12², 13², 14², 15², and 16² There are ...”
December 12, 2018
Brent@GMATPrepNow posted a reply to If 5x + 3y = 17, what is the value of x? in the Data Sufficiency forum
“Target question: What is the value of x? Given: 5x + 3y = 17 Statement 1: x is a positive integer Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here are two: Case a: x = 1 and y = 4 (these values satisfy the given equation, 5x + 3y = 17). In ...”
December 12, 2018
GMATGuruNY posted a reply to A baseball team’s season consists of playing 162 games. At in the Problem Solving forum
“The team has won 58 percent of the games it has played. 58% = 58/100 = 29/50. The fraction in blue implies that the number of wins must be a MULTIPLE OF 29: If 50 games are played, the number of wins = (29/50)(50) = 29. If 100 games are played, the number of wins = (29/50)(100) = 58. If 150 ...”
December 12, 2018
GMATGuruNY posted a reply to Effect of several Tsunamis in the Sentence Correction forum
“A method is a PROCEDURE for accomplishing a particular goal. Since the clause in red does not discuss a procedure, it cannot be summed up as a METHOD.”
December 11, 2018
GMATGuruNY posted a reply to Effect of several Tsunamis in the Sentence Correction forum
“The SC above is modeled -- not altogether successfully -- after SC30 in the OG12: https://www.beatthegmat.com/not-sure-about-the-answer-of-a-question-from-og12-t265701.html Rather than study the SC above, stick to the official SC.”
December 11, 2018
GMATGuruNY posted a reply to The table above shows the number of students in three clubs in the Problem Solving forum
“The values in the chart DOUBLE-COUNT any student who belongs to 2 of the 3 clubs. The totals for chess and drama -- 40 and 30 -- double-count the 10 students who belong to both chess AND drama. The totals for chess and math -- 40 and 25 -- double-count the 5 students who belong to both chess AND ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to How many integers between 324,700 and 458,600 have tens in the Problem Solving forum
“We want to determine how many integers end in 13 For example, 324713, 324813, 324913, 325013, . . . etc. Recognize that, for every 100 consecutive integers, only 1 will end in 13. There are 133,900 integers between 324,700 and 458,600 (since 458,600 - 324,700 = 133,900) Of those 133,900 ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to The quadrilateral ABCD is a square with sides of length 12. in the Problem Solving forum
“This question could take a while to answer (especially if you don''t know where to begin! :-). Fortunately, we can take advantage of an IMPORTANT feature about geometric diagrams on the GMAT: The diagrams in GMAT problem solving questions are DRAWN TO SCALE unless stated otherwise. We have ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to A palindrome is a number that reads the same forward and in the Problem Solving forum
“Take the task of building palindromes and break it into stages. Stage 1: Select the ten-thousands digit We can choose 1, 2, or 3 So, we can complete stage 1 in 3 ways Stage 2: Select the thousands digit We can choose 1, 2, or 3 So, we can complete stage 2 in 3 ways Stage 3: Select ...”
December 11, 2018
GMATGuruNY posted a reply to This year, a woman has a lucrative one-year position. During in the Problem Solving forum
“Let r=9, with the result that 1+r = 10. Her husband can turn each dollar she gives him into 1+r, which will be deposited in a bank account. Let the wife give the husband $1, implying that the husband turns this$1 into 1+r = $10. Thus, the amount deposited into the account =$10. The ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to This year, a woman has a lucrative one-year position. During in the Problem Solving forum
“Let T = the woman''s total salary for the year During this year, she will give a fraction f of her salary to her husband, a private investor, to invest and they will live this year on the remainder. So, the amount SAVED (and then given to huspand)= fT This means the amount SPENT = T - fT ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to A frog is climbing a greasy pole. The frog can climb 2 in the Problem Solving forum
“Let''s solve this by making table Time elapsed | height 1 hours | 4 cm 2 hours | 8 cm REST (slide) 2.5 hours | 7 cm 3.5 hours | 11 cm 4.5 hours | 15 cm REST (slide) 5 hours | 14 cm 6 hours | 18 cm 7 hours | 22 cm REST (slide) 7.5 hours | 21 cm 8.5 hours | 25 cm 9.5 hours | 29 cm ...”
December 11, 2018
Brent@GMATPrepNow posted a reply to Oil, vinegar, and water are mixed in a 3 to 2 to 1 ratio to in the Problem Solving forum
“GIVEN: oil: vinegar : water = 3 : 2 : 1 Let''s first try to use ALL 8 cups of oil Take 3 : 2 : 1 and multiply all 3 parts by 8/3 to get the EQUIVALENT ratio 8 : 16/3 : 8/3 Simplify to get: 8 : 5 1/3 : 2 2/3 So, in this case, the dressing is comprised of 8 cups of oil, 5 1/3 cups of vinegar, ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to Line DB divides Rectangle ABCD into two equal triangles. Is in the Data Sufficiency forum
“IF all 4 sides of the rectangle have EQUAL length (i.e,, the shape is a square), then the diagonal will create two 45-45-90 right triangles. However, if the sides are not all the same length, the resulting triangles will NOT be 45-45-90 right triangles. Cheers, Brent”
December 10, 2018
GMATGuruNY posted a reply to Line DB divides Rectangle ABCD into two equal triangles. Is in the Data Sufficiency forum
“Yes, the line will be a diagonal, but the four angles created by this diagonal will each be 45 degrees only if the rectangle is a square.”
December 10, 2018
Brent@GMATPrepNow posted a reply to A father distributed his total wealth to his two sons. How in the Data Sufficiency forum
“ Given: A father distributed his total wealth to his two sons. Target question: How much wealth did the father have? Statement 1: The elder son received 3/5 of the wealth. Without any dollar values, there''s no way to answer the target question with certainty. So, statement 1 is NOT ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to At what speed was Erik running when he was at the halfway po in the Data Sufficiency forum
“IMPORTANT: The two statements essentially provide the exact same information. If it took Erik 2 hours to travel 10 miles, we can conclude that his average speed was 5 miles per hour. When the two statements provide the same information in a Data Sufficiency question, the correct answer must be ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to [x] is the greatest integer less than or equal to x. What is in the Data Sufficiency forum
“Here are a few similar questions to practice with: - https://www.beatthegmat.com/if-is-the-greatest-integer-less-than-or-equal-to-x-what-t302459.html - https://www.beatthegmat.com/g-x-is-the-greatest-integer-less-than-or-equal-to-x-t298237.html - ...”
December 10, 2018
GMATGuruNY posted a reply to What is the solution set of (1+|x|)(1+x) > 0? in the Problem Solving forum
“x=0 satisfies (1+|x|)(1+x) > 0. Since x=0 is not included in B, C, D or E, eliminate B, C, D and E. The correct answer is A.”
December 10, 2018
GMATGuruNY posted a reply to Tom drives from town A to town B, driving at a constant spee in the Problem Solving forum
“Let the distance between A and B = 120 miles. Since the 120-mile distance between A and B is twice the distance between B and C, the distance between B and C = 60 miles, implying that the total distance = 120+60 = 180 miles. Since the average speed for the 120-mile leg between A and B = 60 ...”
December 10, 2018
Brent@GMATPrepNow posted a reply to When 6 is multiplied by x, the result is the same as when x in the Problem Solving forum
“When 6 is multiplied by x, the result is the same as when x is added to 9 In other words: 6x = 9 + x Subtract x from both sides: 5x = 9 Divide both sides by 5 to get: x = 9/5 Answer: E Cheers, Brent”
December 9, 2018
Brent@GMATPrepNow posted a reply to Three photographers, Lisa, Mike and Norm, take photos of a w in the Problem Solving forum
“We can also solve the question using 1 variable Norms photos number 10 more than twice the number of Lisa''s photos Let x = the number of photographs that Lisa took. So, 2x + 10 = the number of photographs that Norm took. The total of Lisa and Mikes photos is 50 less than the sum of ...”
December 9, 2018
Brent@GMATPrepNow posted a reply to At a certain factory, each employee working the second shift in the Problem Solving forum
“Let''s assign a "nice" value to the number of widgets made by ONE employee. We''ll also assign a nice value to the number of employees on each shift. At a certain factory, each employee working the SECOND shift produced 2/3 as many widgets as each employee working the FIRST shift. ...”
December 9, 2018
GMATGuruNY posted a reply to If the average (arithmetic mean) of five consecutive negativ in the Problem Solving forum
“The value of k is irrelevant. For any set of 5 consecutive integers, the difference between the greatest and least will always be 4. The correct answer is A.”
December 9, 2018
GMATGuruNY posted a reply to Three photographers, Lisa, Mike and Norm, take photos of a w in the Problem Solving forum
“The sum for Lisa and Mike is 50 less than the sum for Norm and Mike. Since Mike is common to both sums, the 50-photo difference must be yielded solely by Lisa and Norm. Implication: Lisa took 50 fewer photos than Norm. We can PLUG IN THE ANSWERS, which represent the number of photos taken ...”
December 9, 2018
GMATGuruNY posted a reply to Andrew sells vintage clothing at a flea market at which he in the Problem Solving forum
“Let h=3. Since an average of $78 is sold per hour, the total revenue for 3 hours = 3*78 = 234. Since the cost for the day is composed of$150 for the table rental and $10 per hour for the assistant, the cost for the day = 150 + 3*10 = 180. P = profit = revenue - cost = 234 - 180 = 54. The ...” December 9, 2018 GMATGuruNY posted a reply to OG2019 -Logical flow in the Critical Reasoning forum “It takes for granted that X implies that X is an ASSUMPTION: a statement that must be true for the conclusion to hold. Thus, when X is negated, the conclusion must be invalidated. B: It takes for granted that the volunteers with the highest levels of self-esteem had better social skills than did ...” December 8, 2018 GMATGuruNY posted a reply to OG2019 -Logical flow in the Critical Reasoning forum “Premise: Volunteers with the highest levels of self-esteem consistently rated themselves as having much better social skills than did the volunteers with moderate levels. Conclusion: Attaining an exceptionally high level of self-esteem greatly improves one’s social skills. The correct answer ...” December 8, 2018 Brent@GMATPrepNow posted a reply to If two of the four expressions x+y, x+5y, x-y, and 5x-y are in the Problem Solving forum “Okay, first recognize that x² - (by)² is a DIFFERENCE OF SQUARES. Here are some examples of differences of squares: x² - 25y² 4x² - 9y² 49m² - 100k² In general, we can factor differences of squares as follows: a² - b² = (a-b)(a+b) So . . . x² - 25y² = (x+5y)(x-5y) 4x² - ...” December 8, 2018 Brent@GMATPrepNow posted a new topic called CHALLENGE: What is the value of k? in the Data Sufficiency forum “What is the value of k? $$(1) k^2-5k-66=0$$ $$(2) \frac{2k}{k^2+5k}=\frac{1}{8}$$ Source: www.gmatprepnow.com Answer: B Estimated difficulty level: 600-650” December 7, 2018 Brent@GMATPrepNow posted a reply to Circle question help in the Problem Solving forum “We''ll begin by arbitrarily placing point A somewhere on the circumference. https://i.imgur.com/hRHtq4o.png So, we want to know the probability that a randomly-placed point B will yield a chord AB that is at least 2 cm long. So, let''s first find a location for point B that creates a chord ...” December 7, 2018 Brent@GMATPrepNow posted a reply to Let C be defined as the sum of all prime numbers between in the Problem Solving forum “C = 2 + 3 + 5 + 7 + 11 + 13 + 17 + 19 + 23 + 29 = 129 So, C/3 = 129/3 = 43 Answer: E Cheers, Brent” December 7, 2018 Brent@GMATPrepNow posted a reply to 2k years ago Frank was 3k years old. In k years Frank's age, in the Problem Solving forum “These kinds of questions (Variables in the Answer Choices - VIACs) can be answered algebraically or using the input-output approach. Mitch has solved the question using the input-output approach, so let''s use the algebraic approach. 2k years ago Frank was 3k years old. We''re given Frank''s ...” December 7, 2018 GMATGuruNY posted a reply to 2k years ago Frank was 3k years old. In k years Frank's age, in the Problem Solving forum “Let k=10. 2k years ago Frank was 3k years old. Since k=10, 20 years ago Frank was 30 years old, implying that his age now = 30+20 = 50. In k years Frank''s age, in years, will be: Since Frank is now 50 years old, Frank''s age in 10 years = 50+10 = 60. The correct answer must yield a value ...” December 7, 2018 GMATGuruNY posted a reply to Which of the following equations is satisfied by x=1+√2? in the Problem Solving forum “Alternate approach: For any quadratic in the form x² + bx + c = 0, where b and c are rational numbers: If one of the roots is m+√n, then the other root is m-√n. Sum of the roots = -b Product of the roots = c Here, since one of the roots is 1+√2, the other root is 1-√2. Thus: -b ...” December 7, 2018 Brent@GMATPrepNow posted a reply to In a 200 member association consisting of men and women, exa in the Problem Solving forum “In order to minimize the number of homeowners, we must MAXIMIZE the number of men in the group, since the proportion of male homeowners (20%) is less than the proportion of female homeowners (25%) So, let''s see what happens if there are 199 men and 1 woman. If 20% (aka 1/5) of the men are ...” December 6, 2018 Brent@GMATPrepNow posted a reply to If all of the telephone extensions in a certain company must in the Problem Solving forum “NOTE: Always SCAN the answer choices before performing any calculations. Here, we notice that the answer choices are pretty small, so if we don''t come up a full solution, we should consider LISTING AND COUNTING We get the following extensions: 1236 1326 1362 1632 2136 2316 3126 3162 ...” December 6, 2018 Brent@GMATPrepNow posted a reply to If all of the telephone extensions in a certain company must in the Problem Solving forum “Take the task of arranging the 4 digits and break it into stages. We’ll begin with the most restrictive stage. Stage 1: Select the digit in the units position Since the 4-digit extension must be EVEN, the unit digit must be either 2 or 6 So, we can complete stage 1 in 2 ways Stage ...” December 6, 2018 Brent@GMATPrepNow posted a reply to What was the revenue that a theater received from the sale in the Data Sufficiency forum “Target question: What was the revenue that a theater received from the sale of 400 tickets Jump straight to . . . Statements 1 and 2 combined The combined statements tell us that 100 tickets sold for the full price of$25 each. The remaining 300 tickets were sold at some reduced price. ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to A certain high school offers two foreign languages, Spanish in the Problem Solving forum
“Another approach is to use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of students, and the two characteristics are: - ...”
December 6, 2018
Brent@GMATPrepNow posted a reply to In year x, it rained on 40% of all Mondays and 20% of all in the Data Sufficiency forum
“In any given year, there will be 52 or 53 Mondays, 52 or 53 Tuesdays, etc. So, it''s impossible to say that it rained on 40% of all Mondays or 20% of all Tuesdays, etc. For example, if there are 52 Mondays, then 40% of 52 = 20.8, which means that it rained on 20.8 days (impossible). Cheers, ...”
December 6, 2018
GMATGuruNY posted a reply to Each day at Dan’s new job, he earns $10 more than the day in the Data Sufficiency forum “Since each payday is$10 more than the preceding payday, the list of 15 paydays constitutes an EVENLY SPACED SET. Statement 1: For any evenly spaced set: Median = Sum/Quantity. Thus: Pay on the 14th day = median of the 3 most recent days = sum/quantity = 690/3 = 330. Since the pay on the ...”
December 6, 2018
GMATGuruNY posted a reply to Tom saved $10,000 at a constant compound interest rate of r in the Problem Solving forum “Original deposit: 10,000. The balance doubles every 10 years. After 10 years, we get: 2*10,000 = 20,000. After 20 years, we get: 2*20,000 = 40,000. After 30 years, we get: 2*40,000 = 80,000. The correct answer is E.” December 6, 2018 GMATGuruNY posted a reply to If a, b, and c are positive integers such that a < b < in the Data Sufficiency forum “Does (a/100) * (b/100) * c = integer? Test integer values such that a < b < c. Statement 1: b = (a/100)¯¹ Thus, b = 100/a. Test the smallest possible value for a. Case 1: a=1 Here, b =100/1 = 100. In this case, (a/100) * (b/100) * c = 1/100 * 100/100 * c = c/100. If c ...” December 5, 2018 Brent@GMATPrepNow posted a reply to Three men sit at a table. One dollar is placed in front of in the Problem Solving forum “Let''s see what happens if a man waits until the last (5th) round to take the money. Round #1:$1 placed in front of the man (but he doesn''t take it) Round #2: Now, $2 placed in front of the man (but he doesn''t take it) Round #3: Now,$4 placed in front of the man (but he doesn''t take it) ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to If a, b, and c are positive integers such that a < b < in the Data Sufficiency forum
“Target question: Is a% of b% of c an integer? This is a great candidate for rephrasing the target question. Aside: We have a free video with tips on rephrasing the target question: a% of b% of c is the same as (a/100)(b/100)(c), which equals abc/10,000 So, we can rephrase the target ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to If w, x, and y are consecutive odd positive integers and w & in the Problem Solving forum
“Here''s a 3rd approach: GIVEN: w, x, and y are consecutive odd positive integers and w < x < y Since consecutive odd integers go up by 2, we can write: x = w + 2, and y = w + 2 + 2 = w + 4 So, y - x - w = (w + 4) - (w + 2) - w = w + 4 - w - 2 - w = 2 - w Since w is an ODD integer, ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to What is the difference between the number of three-member in the Problem Solving forum
“The number of three-member committees that can be formed from a group of nine members Since the order in which we select the 3 people does not matter, we can use combinations. We can choose 3 people from 9 people in 9C3 ways 9C3 = (9)(8)(7)/(3)(2)(1) = 84 three-member committees The total ...”
December 5, 2018
Brent@GMATPrepNow posted a reply to All the 7 books of the fictional character series Horry in the Problem Solving forum
“At $8 per book, the 8 books SHOULD have cost$64 (8 x $8 =$64) However, Harry bought the 8 books for $60 So, the amount Harry saved =$64 - $60 =$4 What is savings percentage for Harry, who bought the whole set together? Percent savings = 100(amount saved)/(original price) = 100(4)/64 = ...”
December 5, 2018
GMATGuruNY posted a reply to If a, b, and c are positive integers, what is the remainder in the Data Sufficiency forum
“Statement 1: No information about b. INSUFFICIENT. Statement 2: No information about a. INSUFFICIENT. Statements combined: Case 1: c=3, with the result that a=3³=27 and that b=(3-2)³=1 In this case, a-b = 27-1 = 26. Dividing 26 by 6, we get: 26/6 = 4 R2 Case 2: c=4, with the ...”
December 5, 2018
GMATGuruNY posted a reply to If w, x, and y are consecutive odd positive integers and w & in the Problem Solving forum
“Test easy cases: 5-3-1 = 1 7-5-3 = -1 The case in green indicates that -1 is a possible value of y-x-w. The correct answer is C.”
December 5, 2018
GMATGuruNY posted a reply to x is a positive number. What is the median of x, √x and x^ in the Data Sufficiency forum
“To determine the median of x, √x and x², we need to know the value of x. Statement 1: Since x is positive, we can safely divide both sides by x: x²/x = x/x x = 1 SUFFICIENT. Statement 2: x² + x + 1 = 3x x² - 2x + 1 = 0 (x-1)² = 0 x = 1 SUFFICIENT. The correct answer is D.”
December 5, 2018
GMATGuruNY posted a reply to A triangle is formed by connecting three randomly chosen ver in the Problem Solving forum
“Let the 6 vertices = A, B, C, D, E and F. P(the triangle includes AT LEAST 1 side of the hexagon) = 1 - P(the triangle includes NO sides of the hexagon). From the 6 vertices, the number of ways to choose 3 to form a triangle = 6C3 = (6*5*4)/(3*2*1) = 20. Of these 20 triangles, only 2 include ...”
December 5, 2018
GMATGuruNY posted a reply to Working together, Machine A and Machine B can produce a in the Data Sufficiency forum
“Since A+B take 4 hours to produce 200 widgets, the combined rate for A+B = w/t = 200/4 = 50 widgets per hour. To determine A''s time to produce 200 widgets, we need to know A''s rate. Question stem, rephrased: What is A''s rate? Statement 1: Since B takes 5 hours to produce 50 widgets, B''s ...”
December 4, 2018
Brent@GMATPrepNow posted a reply to Charlie takes 2.5 hours to fly from Los Angeles to Mexico Ci in the Problem Solving forum
“Average speed = (total distance traveled)/(total travel time) So, Average speed = 1200/2.5 = 2400/5 = 4800/10 = 480 mph Answer: D Cheers, Brent”
December 4, 2018
Brent@GMATPrepNow posted a reply to In her position as a real estate agent, Sarah receives a bon in the Problem Solving forum
“Last week, Sarah earned a $4,000 bonus, which decreased her average bonus amount to$4800. This represents a decrease of 4%. Let x = OLD average bonus amount We can write: x - 0.04x = $4800 Simplify: 0.96x =$4800 Solve: x = $4800/(0.96) =$5000 How many sales has Sarah made? Let n = the ...”
December 4, 2018
GMATGuruNY posted a reply to How many positive two-digit integers have a remainder of 1 w in the Problem Solving forum
“A quick lesson on remainders: Onto the problem at hand: a remainder of 1 when divided by 2 x = 2a + 1 = 1, 3, 5, 7... In other words, x must be ODD. a remainder of 4 when divided by 5 x = 5b + 4 = 4, 9, 14, 19... Since x must be odd, we get: x = 9, 19, 29.... a remainder of ...”
December 4, 2018
Brent@GMATPrepNow posted a reply to If there are 4 pairs of twins, and a committee will be in the Problem Solving forum
“Here''s another approach. Take the task of selecting the 3 committee members and break it into stages. Stage 1: Select the 3 twins from which we will select 1 spouse each. There are 4 sets of twins, and we must select 3 of them. Since the order in which we select the 3 twins does not ...”
December 3, 2018
GMATGuruNY posted a reply to If there are 4 pairs of twins, and a committee will be in the Problem Solving forum
“Number of options for the 1st person = 8. Number of options for the 2nd person = 6. (Of the 7 people left, we can''t use the twin of the 1st person chosen, leaving 7-1= 6 choices.) Number of options for the 3rd person = 4. (Of the 6 people left, we can''t use the twins of the 2 people already ...”
December 3, 2018
GMATGuruNY posted a reply to For each of her sales, a saleswoman receives a commission in the Problem Solving forum
“The first $500 of the$800 sale earns 20% commission, while the remaining $300 earns 30%. Average commission percentage per$800 = (500*20 + 300*30)/800 = (5*20 + 3*30)/8 = 190/8 = 23.75 ≈ 24. The correct answer is B.”
December 1, 2018
Brent@GMATPrepNow posted a reply to For each of her sales, a saleswoman receives a commission in the Problem Solving forum
“Saleswoman receives a commission equal to 20 percent of the first $500 of the total amount of the sale, plus 30 percent of the total amount in excess of$500 If she sold $800, then... Commission = (20 percent of$500) + (30 percent of $300) =$100 + $90 =$190 The saleswoman''s commission ...”
December 1, 2018
Brent@GMATPrepNow posted a reply to Portia purchased a laptop for $480, but after checking the in the Problem Solving forum “Let x = the INTENDED price of the laptop Portia was overcharged by 20% So, x + (20% of x) = the amount Portia paid In other words: x + 0.2x =$480 Simplify: 1.2x = 480 Solve: x = 480/1.2 = 400 So, Portia was SUPPOSED to pay $400, but she actually paid$480 So, Portia was overcharged ...”
December 1, 2018
Brent@GMATPrepNow posted a reply to When a certain tree was first planted, it was 4 feet tall in the Problem Solving forum
“Height of tree on day 0 = 4 Let d = the height increase each year Height of tree at the end of the 1st year = 4+d Height of tree at the end of the 2nd year = 4+d+d = 4 + 2d Height of tree at the end of the 3rd year = 4+d+d+d = 4 + 3d Height of tree at the end of the 4th year = 4+d+d+d+d = 4 + ...”
December 1, 2018
GMATGuruNY posted a reply to When a certain tree was first planted, it was 4 feet tall in the Problem Solving forum
“Let x = the yearly increase. Height after 4 years = 4 + 4x. Height after 6 years = 4 + 6x. At the end of the 6th year, the tree was 1/5 taller than it was at the end of the 4th year. The phrase in red implies the following: The height in the 6th year was 6/5 of the height in the 4th ...”
December 1, 2018
Brent@GMATPrepNow posted a reply to Last Friday a certain shop sold 3/4 of the sweaters in its in the Data Sufficiency forum
“ Given: Last Friday a certain shop sold 3/4 of the sweaters in its inventory. Each sweater sold for $20. Target question: What was the total revenue last Friday from the sale of this sweaters? Statement 1: When the shop opened last Friday, there were 160 sweaters in its inventory. 3/4 ...” November 30, 2018 Brent@GMATPrepNow posted a reply to When running a mile during a recent track meet, Nuria was in the Problem Solving forum “The long approach is to meticulously convert 11/25 of a minute to seconds, and then ADD that unaccounted time to Nuria''s recorded time (of 5 minutes, 44 seconds) However, when we check the answer choices before performing any calculations (ALWAYS check the answer choices before performing any ...” November 30, 2018 GMATGuruNY posted a reply to If k is a positive integer and n=(k-1)k(k+1), is n a multipl in the Data Sufficiency forum “Every other even integer is a MULTIPLE OF 4: 2, 4, 6, 8, 10, 12... Thus, the product of two consecutive even integers = product of a multiple of 4 and an even non-multiple of 4 = MULTIPLE OF 8: 2*4 = 8 4*6 = 2*2*2*3 = 8*3 10*12 = 2*5*2*2*3 = 8*15 Statement 1: Since k is odd, k-1 and k+1 ...” November 30, 2018 GMATGuruNY posted a reply to If x^2=x+1, then x^4=? in the Problem Solving forum “Squaring both sides, we get: (x²)² + (x+1)² x⁴ = x² + 2x + 1 Substituting x²=x+1 into x⁴ = x² + 2x + 1, we get: x⁴ = (x+1) + 2x + 1 x⁴ = 3x + 2 The correct answer is A.” November 30, 2018 GMATGuruNY posted a reply to Is the positive integer p a multiple of 50? in the Data Sufficiency forum “Any integer that is a multiple 10 is also a multiple of 5. Implication: Any integer that satisfies Statement 1 will also satisfy Statement 2. Both statements are satisfied by the following cases: Case 1: p=10, which is a multiple of 10 (and thus is also a multiple of 5) In this case, p is NOT a ...” November 30, 2018 GMATGuruNY posted a reply to The point A, B, C, and D are on the number line, not in the Data Sufficiency forum “The drawings below satisfy both statements: http://s4.postimage.org/1yjxdhskk/ABCD_number_line.jpg Since in the first case BD=1 and in the second case BD=17, the two statements combined are insufficient. The correct answer is E.” November 30, 2018 GMATGuruNY posted a reply to In a business school case competition, the top three teams in the Problem Solving forum “Case 1: Team A wins a prize, with the result that Team B must win a prize Number of prizes that could be won by A = 3. Number of remaining prizes that could be won by B = 2. Number of teams that could win the third prize = 4. (Any of the 4 remaining teams.) To combine these options, we ...” November 30, 2018 GMATGuruNY posted a reply to The juice stall at the circus stocked just 2 brands of in the Problem Solving forum “Let n=50, implying that 50% of the sold juice packs are A, while the other half are B. In other words, the store sells an EQUAL NUMBER of each type of juice pack. Let the store sell 2 OF EACH TYPE of juice pack. Revenue from two$1 packs of A = 2*1 = 2. Revenue from two $1.5 packs of B = ...” November 29, 2018 Brent@GMATPrepNow posted a reply to GMAT PREP CR... why is A wrong? in the Critical Reasoning forum “A student asked me to answer this question, so here it goes . . . 1) Read the question stem to determine the question type. Tricky! With fill-in-the-blank questions, it''s often difficult to determine the question type. The last sentence reads Unitron is not going to hire department heads ...” November 29, 2018 Brent@GMATPrepNow posted a reply to New cars leave a car factory in a repeating pattern of red, in the Problem Solving forum “Let''s examine the pattern. CAR # | color 1 | red 2 | blue 3 | black 4 | gray 5 | red 6 | blue 7 | black 8 | gray 9 | red . . . The pattern REPEATS EVERY 4 CARS. So, we say the pattern has CYCLE 4 Also, notice that every car # that''s divisible by 4 is gray So, let''s find a ...” November 29, 2018 GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum “Let James'' rate = 3 mph. James started from his home and drove eastwards at a constant speed. Exactly 90 minutes after James stated from his home, his brother Patrick started from the same point and drove in the same direction as James did at a different constant speed. Patrick overtook James ...” November 29, 2018 GMATGuruNY posted a reply to The equation of a circle in the x-y coordinate plane is x^2 in the Problem Solving forum “The equation for a circle with its center at the origin and a radius of r is as follows: x² + y² = r². Thus, x² + y² = 25 is a circle with its center at the origin and a radius of 5. A point on this circle will have integer coordinates in three cases: Case 1: The radius is horizontal ...” November 29, 2018 Brent@GMATPrepNow posted a reply to If each of the two digits X and Y is distinct, is the two di in the Data Sufficiency forum “Target question: Is the two-digit integer xy prime? Given: Each of the two digits x and y is distinct Statement 1: Each of the digits x and y is the sum of 2 distinct single digit prime numbers. Let''s TEST some values. There are several values of x and y that satisfy statement 1. Here ...” November 29, 2018 Brent@GMATPrepNow posted a reply to Joan spent$10 to buy at least one piece each of apples and in the Data Sufficiency forum
“Target question: How many apples did Joan buy? Given: Joan spent $10 to buy at least one piece each of apples and oranges at a store where each apple cost$2 and each orange cost $1. Since there are only a handful of possible outcomes, we might benefit from quickly listing them: i) Joan ...” November 29, 2018 Brent@GMATPrepNow posted a reply to If 320 people attended the wedding and 200 attendees drank in the Data Sufficiency forum “This question is somewhat ambiguous, since it''s hard to say whether "nondrinkers" in statement 1 refers to people who drank neither beer nor wine, or did not drink beer. I''m assuming that it means to not drink beer, so I''ve add that to the question below. One approach is to use ...” November 28, 2018 Brent@GMATPrepNow posted a reply to Difficult Manhatan Problem in the Problem Solving forum “Target question: What is the hundreds digit of the product AB? Given: The difference between positive two-digit integer A and the smaller two-digit integer B is twice A‘s units digit Let x = the tens digit of A, and let y = the units digit of A So, the VALUE of A = 10x + y From the ...” November 28, 2018 Brent@GMATPrepNow posted a reply to If a child is randomly selected from Columbus Elementary in the Data Sufficiency forum “Target question: What is the probability that the child will be a boy? This is a good candidate for rephrasing the target question. Let G = # of girls in the school Let B = # of boys in the school So, G + B = total number of children in the school So, P(selected child is a boy) = B/(G + B) ...” November 28, 2018 Brent@GMATPrepNow posted a reply to A club has 10 members. One president and two vice-presidents in the Problem Solving forum “Take the task of selecting the president and two vice-presidents and break it into stages. Stage 1: Select the president There are 10 people to choose from. So, we can complete stage 1 in 10 ways Stage 2: Select two people to be the vice-presidents Since the order in which we select the ...” November 28, 2018 Brent@GMATPrepNow posted a reply to On a partly cloudy day, Derek decides to walk back from work in the Problem Solving forum “Let''s PLUG IN a nice value for the total distance traveled. If Derek''s average speed is 2.8 mph, then let''s say that he traveled a total of 28 miles. At an average rate of 2.8 mph, a 28 mile trip will take 10 hours. Since Derek''s average speed is BETWEEN 2 and 3 mph, we can conclude that ...” November 28, 2018 GMATGuruNY posted a reply to On a partly cloudy day, Derek decides to walk back from work in the Problem Solving forum “The average speed -- 2.8 miles per hour -- must be BETWEEN the two individual rates (s and s+1). Thus, s = 2 miles per hour and s+1 = 3 miles per hour. We can PLUG IN THE ANSWERS, which represent the fraction traveled at 2 miles per hour. When the correct fraction is plugged in, the average ...” November 28, 2018 GMATGuruNY posted a reply to Eight consecutive integers are selected from the integers 1 in the Data Sufficiency forum “When consecutive positive integers are divided by positive integer x, the resulting remainders also are consecutive: If x=4: 16/4 = 4 R0. 17/4 = 4 R1. 18/4 = 4 R2. 19/4 = 4 R3. 20/4 = 5 R0. From here, the cycle of remainders will repeat: 0,1,2,3,0,1,2,3... The smallest remainder is 0. The ...” November 28, 2018 GMATGuruNY posted a reply to A club has 10 members. One president and two vice-presidents in the Problem Solving forum “Number of options for president = 10. (Any of the 10 members.) From the remaining 9 members, the number of ways to choose 2 to serve as vice-president = 9C2 = (9*8)/(2*1) = 36. To combine these options, we multiply: 10*36 = 360. The correct answer is E.” November 28, 2018 Brent@GMATPrepNow posted a reply to The weights of four packages are 1, 3, 5, and 7 pounds, resp in the Problem Solving forum “That''s MUCH better than my solution!! Cheers, Brent<i class="em em---1"></i>” November 27, 2018 Brent@GMATPrepNow posted a reply to The weights of four packages are 1, 3, 5, and 7 pounds, resp in the Problem Solving forum “For each answer choice, if we CAN create the total given weight, then we can ELIMINATE that answer choice. a) 9 = 1 + 3 + 5 ELIMINATE b) 10 = 3 + 7 ELIMINATE c) 12 = 5 + 7 ELIMINATE d) 13 = 1 + 5 + 7 ELIMINATE By the process of elimination, the correct answer is E Cheers, Brent” November 27, 2018 Brent@GMATPrepNow posted a reply to If 1+2+2^2+... +2^n=2^{n+1}-1, what is the largest prime fac in the Problem Solving forum “GIVEN: 1 + 2 + 2^2 + ... + 2^n = 2^{n+1} - 1 So, 1 + 2 + 2^2 + ... + 2^7 = 2^{7+1} - 1 = 2^8 - 1 If we recognize that the above expression is a difference of squares, we can factor it to get.... 2^8 - 1 = (2^4 + 1)(2^4 - 1) = (2^4 + 1)(2^2 + 1)(2^2 - 1) = (16 + 1)(4 + 1)(4 - 1) = ...” November 27, 2018 Brent@GMATPrepNow posted a reply to How many integers from 0 to 50, inclusive, have a remainder in the Problem Solving forum “When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k are: 1, 1+5, 1+(2)(5), 1+(3)(5), ...” November 27, 2018 Brent@GMATPrepNow posted a reply to Is b even? in the Data Sufficiency forum “Target question: Is b even? KEY POINT: We are not told that a and b are INTEGERS. As such, we can jump straight to. . . . Statements 1 and 2 combined There are several values of a and b that satisfy BOTH statements. Here are two: Case a: a = 4 and b = 2. Notice that a/b = 4/2 = 2, ...” November 27, 2018 Brent@GMATPrepNow posted a reply to In the rectangular coordinate system shown above, does the in the Data Sufficiency forum “Target question: Does line k intersect quadrant II? Statement 1: The slope of k is -1/6 Here are a few lines with slope -1/6 https://i.imgur.com/1p6USLh.png KEY CONCEPT: As we travel from right to left along a line with slope -1/6, we keep moving up. So, at some point, the line will ...” November 27, 2018 Brent@GMATPrepNow posted a reply to A certain recipe calls for 2 cups of sugar and 3 1/2 cups of in the Problem Solving forum “Judging from the OA, I''ve added some key text below A certain recipe calls for 2 cups of sugar and 3 1/2 cups of flour So sugar/flour = 2/3.5 Check answer choices . . . . not there. Looks like we need to create a ratio that''s EQUIVALENT to 2/3.5 Multiply top and bottom by 2 to get ...” November 27, 2018 Brent@GMATPrepNow posted a reply to When the positive integer x is divided by 6, the remainder in the Problem Solving forum “Good catch - thanks Fabio! I''ve edited my response accordingly. Cheers, Brent” November 26, 2018 Brent@GMATPrepNow posted a reply to In a certain state, gasoline stations compute the price per in the Problem Solving forum “In a certain state, gasoline stations compute the price per gallon "p", in dollars, charged at the pump by adding a 4 percent sales tax to the dealer''s price per gallon "d", in dollars . . . We can write: p = d + 4% of d = d + 0.04d = 1.04d So, we have: p = 1.04d . . . ...” November 26, 2018 Brent@GMATPrepNow posted a reply to When the positive integer x is divided by 6, the remainder in the Problem Solving forum “APPROACH#2 When the positive integer x is divided by 6, the remainder is 4 In other words, x is 4 greater than some multiple of 6 We can write: x = 6k + 4, where k is an integer If x = 6k + 4, we can also write: x = 6k + 3 + 1 Factor to get: x = 3(2k + 1) + 1 Since 2k+1 must be an integer, ...” November 26, 2018 Brent@GMATPrepNow posted a reply to When the positive integer x is divided by 6, the remainder in the Problem Solving forum “----ASIDE------------------- When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k are: 1, ...” November 26, 2018 Brent@GMATPrepNow posted a reply to A chili recipe calls for the final mixture to consist of 1/2 in the Problem Solving forum “A chili recipe calls for the final mixture to consist of 1/2 meat and 1/3 beans, with the remainder an even mixture of sauce and various spices Let''s see what fraction of the final mixture is sauce and various spices 1/2 + 1/3 = 3/6 + 2/6 = 5/6 If 5/6 of the mixture is meat and beans, then the ...” November 26, 2018 Brent@GMATPrepNow posted a reply to A store sells only two types of shirts, branded and in the Data Sufficiency forum “ Given: All the branded shirts are priced at$60 per unit and all the non-branded shirts are priced at $20 per unit. On a certain day, the store sold a total of 30 shirts. Let B = # of branded shirts sold Let N = # of non-branded shirts sold If a TOTAL of 30 shirts were sold, we can write: N + ...” November 26, 2018 Brent@GMATPrepNow posted a reply to Of the 4,800 voters who voted for or against Resolution K, in the Data Sufficiency forum “Target question: What was the total number of female voters who voted for Resolution K? When solving Data Sufficiency questions, it''s important that you don''t perform more calculations than are necessary. So, for this question, we need only determine whether or not we have sufficient ...” November 26, 2018 Brent@GMATPrepNow posted a reply to If x and y are nonnegative integers, what is the value of y? in the Data Sufficiency forum “The above solutions are great. I just wanted to add that whenever you''re told that a value is non-negative on the GMAT, you should be sure to consider what happens when that value equals zero Keep in mind that, if the test-makers wanted to restrict a value to POSITIVE values only, then they''d ...” November 25, 2018 Brent@GMATPrepNow posted a reply to If n is the smallest integer such that 432 times n is the in the Problem Solving forum “IMPORTANT CONCEPT: The prime factorization of a perfect square (the square of an integer) will have an even number of each prime For example: 400 is a perfect square. 400 = 2x2x2x2x5x5. Here, we have four 2''s and two 5''s This should make sense, because the even numbers allow us to split the ...” November 25, 2018 Brent@GMATPrepNow posted a reply to Set P {a, b, c, d, e, f, g} Set Q {a, b, c, d, e, f} If a, b in the Problem Solving forum “The key here is MUST be true. So, if we can find an example in which a statement is NOT true, then we can ELIMINATE it. We have: Set P {a, b, c, d, e, f, g} Set Q {a, b, c, d, e, f} I''ll make the extra value red so it''s easier to compare the two sets So, the sets COULD be: Set P {1, 2, ...” November 25, 2018 Brent@GMATPrepNow posted a reply to Every object in a box is either a sphere or a cube, and ever in the Data Sufficiency forum “Target question: How many objects are in the box? Given: Every object in a box is either a sphere or a cube, and every object in the box is either red or green. We can solve this using the Double Matrix Method. This technique can be used for most questions featuring a population in which ...” November 25, 2018 GMATGuruNY posted a reply to Twelve identical machines, running continuously at the same in the Problem Solving forum “One approach is to use the following equation: (machines)(time) / output = (machines)(time) / output In the equation above: Machines and time are INVERSELY PROPORTIONAL. As the number of machines increases, the amount of time required to produce the same output decreases. Machines and ...” November 24, 2018 GMATGuruNY posted a reply to In a plane, there are two parallel lines. One line has 5 in the Problem Solving forum “One approach: Good Cases = Total Cases - Bad Cases. Total Cases: From 9 points, the number of ways to choose 3 = 9C3 = (9*8*7)/(3*2*1) = 84. Bad Case 1: Choosing 3 collinear points from the 5-point line, with the result that a triangle cannot be formed From the 5 points on this line, the ...” November 24, 2018 Brent@GMATPrepNow posted a reply to Last month, a florist gave 7 percent of her sales revenue to in the Problem Solving forum “Choose a "nice" number for the sales revenue Let$100 = LAST MONTH''s revenue So, $120 = THIS MONTH''s revenue (since sales were up 20 percent from last month) LAST month, a florist gave 7 percent of her sales revenue to her employees in bonuses So, bonuses = 7% of$100 = $7 ...” November 23, 2018 Brent@GMATPrepNow posted a reply to In a plane, there are two parallel lines. One line has 5 in the Problem Solving forum “There are two ways in which we can create a triangle. #1) Select 2 points from the 5-point line and select 1 point from the 4-point line. #2) Select 2 points from the 4-point line and select 1 point from the 5-point line. #1) Select 2 points from the 5-point line and select 1 point from the ...” November 23, 2018 Brent@GMATPrepNow posted a reply to GMAT PREP KAPLAN VIDEO in the The 60-Day GMAT Study Guide forum “Thanks for the heads up. This video should serve as a replacement: https://www.gmatprepnow.com/module/general-gmat-strategies/video/1250 Cheers, Brent” November 23, 2018 Brent@GMATPrepNow posted a reply to Alan and Peter are cycling at different constant rates on a in the Data Sufficiency forum “ Given: Alan is NOW 3 miles ahead of Peter Target question: How many minutes from now will Peter be 1 mile ahead of Alan? Statement 1: ONE HOUR AGO, Alan was 7 miles ahead of Peter. Alan is NOW 3 miles ahead of Peter So, in one hour, the GAP between Alan and Peter decreased by 4 miles ...” November 23, 2018 Brent@GMATPrepNow posted a reply to List M consists of 50 decimals, each of which has a value be in the Problem Solving forum “Let''s examine the EXTREME CASES S - T = x percent of T So, S - T = (x/100)T Divide both sides by to get: (S - T)/T = x/100 Multiply both sides by 100 to get: x = 100(S - T)/T First, we we''ll MINIMIZE the value of x by minimizing the value of S - T and maximizing the value of T. This ...” November 23, 2018 Brent@GMATPrepNow posted a reply to R and S can complete a certain job in 6 and 4 days respectiv in the Problem Solving forum “Let''s assign a "nice" value to the job, a value that works well with the given values (6 days and 4 days ). So, let''s say the ENTIRE job is to make 24 widgets R can complete a certain job in 6 days In other words, R can make 24 widgets in 6 days So, R can make 4 widgets per day ...” November 23, 2018 Brent@GMATPrepNow posted a reply to A certain telephone company offers two plans, A and B. Under in the Problem Solving forum “Let x = the duration of the phone call (in minutes) Under plan A, the company charges a total of$0.60 for the first 7 minutes of each call and $0.06 per minute thereafter. So, the TOTAL cost =$0.60 + (x - 7 minutes)($0.06) = 0.60 + (0.06x - 0.42) = 0.06x + 0.18 Under plan B, the company ...” November 23, 2018 GMATGuruNY posted a reply to Find x^4 + 1/x^4 if x – 1/x = 2. in the Problem Solving forum “(x – 1/x)² = 2² x² + 1/x² - 2(x)(1/x) = 4 x² + 1/x² - 2 = 4 x² + 1/x² = 6 (x² + 1/x²)² = 6² x⁴ + 1/x⁴ + (2)(x²)(1/x²) = 36 x⁴ + 1/x⁴ + 2 = 36 x⁴ + 1/x⁴ = 34. The correct answer is D.” November 23, 2018 GMATGuruNY posted a reply to If n is an integer greater than 1, what is the value of n? in the Data Sufficiency forum “Since the prompt indicates that n is an integer greater than 1, the case in red is not possible. The only value that satisfies Statement 2 is n=2, making Statement 2 SUFFICIENT. The correct answer thus is not C but B.” November 23, 2018 GMATGuruNY posted a reply to What is the sum of the prime factors of 2^8-1? in the Problem Solving forum “Alternate approach: 2⁸ - 1 = 256 - 1 = 255 = 5*51 = 5*3*17. Sum of the prime factors = 5+3+17 = 25. The correct answer is E.” November 22, 2018 GMATGuruNY posted a reply to June 25, 1982, fell on a Friday. On which day of the week in the Problem Solving forum “Between 1982 and 1987 are 4 non-leap years and 1 leap year. Each non-leap year is composed of 365 days; a leap year is composed of 366 days. Thus, from June 25, 1982 to June 25, 1987, the total number of days = 4(365) + 366. Since June 25, 1982 is a Friday, every passing of 7 days will yield ...” November 22, 2018 GMATGuruNY posted a reply to A man walking at a constant rate of 4 miles per hour is pass in the Problem Solving forum “(man''s rate)/(woman''s rate) = (4 mph)/(20 mph) = 1/5. Between the moment when the woman passes the man and the moment when she stops to wait, the woman and the man each travel for 5 minutes. During these 5 minutes, the woman travels x miles. Since the man''s rate is 1/5 the woman''s rate, the ...” November 21, 2018 Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum “The Something Method for solving certain equations Video: https://www.youtube.com/watch?v=mmTisgtNfTI Cheers, Brent” November 21, 2018 GMATGuruNY posted a reply to Six countries in a certain region sent a total of 75 in the Data Sufficiency forum “Let the 6 countries be A, B, C, D, E and F. The question stem asks whether A≥10. Plug in A=10 (which satisfies statement 2 and is at least 10) and A=9 (which also satisfies statement 2 but is NOT at least 10). To save time, let F=41, which satisfies statement 1. Case 1: Total = 75, ...” November 21, 2018 Brent@GMATPrepNow posted a reply to If m represents the slope of a line in the coordinate geomet in the Data Sufficiency forum “Target question: Does the line intersect quadrant III? Jump straight to... Statements 1 and 2 combined Here are two scenarios that satisfy BOTH statements: Case a: m = 3 https://i.imgur.com/2SVui9E.png In this case, the answer to the target question is YES, the line DOES intersect ...” November 21, 2018 Brent@GMATPrepNow posted a reply to In the first year of a pyramid scheme, John convinced y of in the Data Sufficiency forum “Target question: What was the value of y? Statement 1: The revenue for the website that year was$36,000. First round of "investors": y people paying $30 each = 30y dollars Second round of "investors": y² people paying$15 each = 15y² dollars Total revenue = 15y² + ...”
November 21, 2018
Brent@GMATPrepNow posted a reply to Missing day 20 in the The 60-Day GMAT Study Guide forum
“Done! Cheers, Brent”
November 21, 2018
GMATGuruNY posted a reply to If n is an integer greater than 1, what is the value of n? in the Data Sufficiency forum
“Statement 1: Here, n can be any prime number. INSUFFICIENT. Statement 2: (n+2)/n = n/n + 2/n = 1 + 2/n. Given that n must be an integer, 1 + 2/n will yield an integer value only if n is a FACTOR OF 2. Factors of 2: 1 and 2. Since n must be greater than 1, n=2. SUFFICIENT. The correct ...”
November 21, 2018
Brent@GMATPrepNow posted a reply to Luxo paint contains only alcohol and pigment. What is the in the Data Sufficiency forum
“Target question: What is the ratio of alcohol to pigment in Luxo paint? Given: Luxo paint contains ONLY alcohol and pigment. Statement 1: Exactly 7 ounces of pigment are contained in a 12-ounce can of Luxo paint. If 7 of the 12 ounces of paint are PIGMENT, then the remaining 5 ounces ...”
November 21, 2018
Brent@GMATPrepNow posted a reply to A children's theater sels tickets to a show. Tickets for in the Data Sufficiency forum
“ Given: Tickets for children cost $10 and tickets for adults cost$35. Ticket revenues from the last performance were $390 Let A = # of adults in attendance Let C = # of children in attendance So, we can write: 35A + 10C = 390 Since A and C must be POSITIVE INTEGERS, there are not many ...” November 20, 2018 GMATGuruNY posted a reply to A number when divided by 4 and 5 leaves remainders 1 and 4 in the Problem Solving forum “Please fix the prompt, which has been transcribed incorrectly. It should include the word in red:” November 20, 2018 Brent@GMATPrepNow posted a reply to A number when divided by 4 and 5 leaves remainders 1 and 4 in the Problem Solving forum “When it comes to remainders, we have a nice rule that says: If N divided by D, leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k are: 1, 1+5, 1+(2)(5), 1+(3)(5), ...” November 20, 2018 GMATGuruNY posted a reply to A woman has seven cookies - four chocolate chip and three in the Problem Solving forum “Alternate approach: Case 1: Deborah and Kim each receive an oatmeal cookie In this case, 4 chocolate chip cookies and 1 oatmeal cookie remain. The remaining oatmeal cookie has 5 options: Nicole, Ronit, Mark, Terrance, or no one. Total ways = 5. Case 2: Deborah and Kim each receive a ...” November 20, 2018 Brent@GMATPrepNow posted a reply to The number line above represents which of the following in the Problem Solving forum “We can also solve the question by testing the answer choices Here''s what I mean: The diagram tells us that x= 0 is a solution to the inequality. When we check the answer choices, we see that answer choice D (1 < 2x < 3) does NOT have x = 0 as a solution. When we let x = 0, the ...” November 19, 2018 Brent@GMATPrepNow posted a reply to If n is an integer between 30 and 50 inclusive, what is the in the Data Sufficiency forum “Target question: What is the value of n? Given: n is an integer between 30 and 50 inclusive Statement 1: When n is divided by 8, the remainder is 7 ------ASIDE-------------------------------------- When it comes to remainders, we have a nice rule that says: If N divided by D leaves ...” November 19, 2018 Brent@GMATPrepNow posted a reply to When sold at a 40% discount, a sweater nets the merchant a in the Problem Solving forum “Let''s work BACKWARDS. Let''s say the WHOLESALE price was$100 the merchant made a net profit of 20% on the wholesale cost (which was $100) So, the merchant sold the sweater for$120 Let M = the markup price on the label (before any discounts). So, 40% less than M = $120 In other ...” November 19, 2018 GMATGuruNY posted a reply to The Lewiston Road Race is how many kilometers long? in the Data Sufficiency forum “Statement 1: Rate and time have a RECIPROCAL relationship. A rate ratio of (40kph) : (50kph) = 4:5 implies a time ratio of 5:4 = 10:8. The time ratio in blue implies that -- for the time at 40kph to be 2 hours more than the time at 50kph -- the time at 40kph must be 10 hours, while the time at ...” November 17, 2018 Brent@GMATPrepNow posted a reply to Kevin buys beer in bottles and cans. He pays$1.00 for each in the Data Sufficiency forum
“Target question: How many bottles of beer did Kevin buy? Given: Kevin pays $1.00 for each can of beer and$1.50 for each bottle of beer. Kevin buys a total of 15 bottles and cans of beer Let C = the NUMBER of Cans that Kevin bought Let B = the NUMBER of Bottles that Kevin bought So, we can ...”
November 16, 2018
GMATGuruNY posted a reply to Tim and Glenn are running laps around a circular track. in the Data Sufficiency forum
“Statement 1: The TIME RATIO for Tim and Glenn = 48:60 = 4:5. Since time and rate have a RECIPROCAL relationship, the RATE RATIO for Tim and Glenn = 5:4. Implication: For every 5 laps that Tim runs, Glenn runs only 4 laps. Thus, after running 5 laps, Tim will have run 1 more lap than Glenn. ...”
November 16, 2018
Brent@GMATPrepNow posted a reply to What is the least possible product of 4 different integers, in the Problem Solving forum
“We want values with the greatest MAGNITUDE So (10)(9)(8)(-5) = -3600 Answer: -3600 Answer: B”
November 16, 2018
Brent@GMATPrepNow posted a reply to A reatil appliance store priced a video recorder at 20 in the Problem Solving forum
“A retail appliance store priced a video recorder at 20 percent above the wholesale cost of $200 20% of$200 = $40 So, the retail price =$200 + $40 =$240 If a store employee applied the 10 percent employee discount to the retail price to buy the recorder, how much did the employee pay for the ...”
November 16, 2018
Brent@GMATPrepNow posted a reply to Planning is in progress for a fenced, rectangular playground in the Problem Solving forum
“It''s a good idea to first try to understand what the graph is telling us. For example, the leftmost point on the curve has the coordinates (10, 340) This tells us that, if the length of the playground is 10 meters, then a total of 340 meters of fencing is required. This makes sense, since we ...”
November 16, 2018
Brent@GMATPrepNow posted a reply to When a certain tree was first planted, it was 4 feet tall, in the Problem Solving forum
“Height of tree on day 0 = 4 Let d = the height increase each year Height of tree at the end of the 1st year = 4+d Height of tree at the end of the 2nd year = 4+d+d = 4 + 2d Height of tree at the end of the 3rd year = 4+d+d+d = 4 + 3d Height of tree at the end of the 4th year = 4+d+d+d+d = 4 + ...”
November 16, 2018
Brent@GMATPrepNow posted a reply to In the rhombus ABCD, the length of diagonal BD is 6 and the in the Problem Solving forum
“In a rhombus, the diagonals are perpendicular bisectors. http://i1168.photobucket.com/albums/r500/GMATPrepNow/rhmbs1_zps1nyufj6q.png So, we can add our lengths as follows. http://i1168.photobucket.com/albums/r500/GMATPrepNow/rhmbs2_zpskyv3wwkl.png From here, if we focus on one of the 4 ...”
November 16, 2018
GMATGuruNY posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom in the Problem Solving forum
“Let the one-bedroom rent = $2 per month, implying that the two-bedroom rent = 2 + (50% of 2) = 2 + 1 =$3 per month. Since the rent for a one-bedroom apartment = $2 per month, the total amount to rent a one-bedroom apartment for 12 months = 2*12 =$24. For $24, the number of months yielded for a ...” November 16, 2018 Brent@GMATPrepNow posted a reply to If xy is not equal to zero, what is the ratio of x to y? in the Data Sufficiency forum “NOTE: We can write the ratio x:y as a fraction x/y Target question: What is the value of x/y ? Statement 1: 3x = 4y Divide both sides by y to get: 3x/y = 4 Divide both sides by 3 to get: x/y = 4/3 So, the answer to the target question is x/y = 4/3 Since we can answer the target question ...” November 16, 2018 Brent@GMATPrepNow posted a reply to At the Trenchard Oaks apartment complex, a two-bedroom in the Problem Solving forum “A fast and easy approach is to assign a "nice" value to the monthly rent of a ONE-bedroom apartment. Let''s say the rent on a ONE-bedroom apartment is$100 per month A two-bedroom apartment costs 50% more to rent than a one-bedroom apartment 50% of $100 =$50 So, the rent on a ...”
November 15, 2018
Brent@GMATPrepNow posted a reply to If line k in the xy-coordinate plane has the equation Ax + B in the Data Sufficiency forum
“ Given: Line k has the equation Ax + By = C Target question: What is the slope of line k ? This is a good candidate for rephrasing the target question. Let''s take the given equation Ax + By = C and rewrite it in slope y-intercept form, y = mx + b, where m = slope and b = y-intercept ...”
November 15, 2018
Brent@GMATPrepNow posted a reply to What is the ratio of x:y:z? in the Data Sufficiency forum
“Target question: What is the ratio of x:y:z? Statement 1: xy = 14 In information about z Statement 1 is NOT SUFFICIENT Statement 2: yz = 21 In information about x Statement 2 is NOT SUFFICIENT Statements 1 and 2 combined There are several values of x, y and z that satisfy BOTH ...”
November 15, 2018
Brent@GMATPrepNow posted a reply to If xy : yz : zx = 1:2:3, then what is x : y : z ? in the Problem Solving forum
“Let''s focus on pairs of values If xy : yz : zx = 1:2:3, then we know that xy : yz = 1:2 Take xy : yz and divide both sides by y to get the EQUIVALENT ratio x:z This means x:z = 1:2 Check the answer choices... A. 2 : 3 : 6 this answer choice says x:z = 2:6. We need x:z = 1:2 ELIMINATE A ...”
November 15, 2018
Brent@GMATPrepNow posted a reply to Over a four-game stretch, Dennis's bowling scope average 240 in the Problem Solving forum
“In other words, an increase from 240 to 300 represents what kind of percent increase? Percent increase = (100)(new - old)/old = (100)(300 - 240)/240 = (100)(60)/240 = (100)(1/4) = 25% Answer: B Cheers, Brent”
November 15, 2018
GMATGuruNY posted a reply to A certain store will order 25 crates of apples. The apples in the Problem Solving forum
“Let W = Winesap crates, M = McIntosh crates, and R = Roma crates. Since a total of 25 crates are ordered, we get: W + M + R = 25. To MINIMIZE the value of W, we must MAXIMIZE the values of M and R. Since the store is to order more crates of Winesap than crates of McIntosh and more crates of ...”
November 15, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“The prompt states: Every day, the two machines operate constantly from 08:00 to 18:00. As shown in my post above, Statement 2 yields the following rate ratio: (W alone) : (W and D together) = 1:5. The rate ratio indicates that -- of every 5 kg produced when W and D work together from 8:00 to ...”
November 15, 2018
GMATGuruNY posted a reply to Organized in 1966 by the Fish and Wildlife in the Sentence Correction forum
“Generally, for + VERBing is an ADJECTIVE serving to modify a NOUN. A: The Breeding Bird Survey uses annual roadside counts along established routes for monitoring. Here, for monitoring seems to be an ADJECTIVE modifying routes, implying that the ROUTES were designed FOR MONITORING. Not the ...”
November 15, 2018
Brent@GMATPrepNow posted a reply to The table above shows the distribution of tests scores for a in the Problem Solving forum
“Since we have an ODD number of values, the median will be the MIDDLEMOST value. In other words, if we arrange all 73 values in ASCENDING order, the median will be the 37th value (i.e., 36 values are below and 36 values are above). The table says the first 2 scores in the 50-59 range. So, the 1st ...”
November 15, 2018
Brent@GMATPrepNow posted a reply to # X-Axis Intercepts in the Problem Solving forum
“Let''s find some points that lie on each of the curves. So, for each equation, we''ll find a pair of values (an x-value and a y-value) that satisfy each equation. We''ll do so by plugging in some x-values and calculating the corresponding y-values. Let''s start with x = 0 Plug x = 0 into ...”
November 14, 2018
GMATGuruNY posted a reply to A marzipan factory has two machines producing marzipan. in the Data Sufficiency forum
“Statement 1: Let N = 50 kg. Since W and D produce the entire 50 kg over the 10 hours between 8:00 and 18:00, the combined rate for W and D = 50/10 = 5 kg per hour. Since W takes 25 hours to produce N/2 = 25 kg, W''s rate alone = w/t = 25/25 = 1 kg per hour. Of every 5 kg produced each hour ...”
November 14, 2018
GMATGuruNY posted a reply to If x and y are unknown positive integers, is the mean of the in the Data Sufficiency forum
“Known values, in ascending order: 1, 5, 6, 7 Statement 1: x+y = 7 Mean = sum/quantity = (1+5+6+7+x+y)/6 = (1+5+6+7+7)/6 = 26/6 = 13/3 = 4.33. Text EXTREMES. Case 1: x and y are far from each other If x=1 and y=6, we get: 1, 1. 5, 6, 6, 7 Median = (5+6)/2 = 11/2 = 5.5 Case 2: x and y ...”
November 14, 2018
GMATGuruNY posted a reply to How many positive two-digit numbers yield a remainder of 1 in the Problem Solving forum
“Let x = the two-digit number. Since dividing by 4 leaves a remainder of 1, x is equal to one more than a multiple of 4: x = 4k + 1 Since dividing by 14 leaves a remainder of 1, x is equal to one more than a multiple of 14: x = 14m + 1 Since the two expressions in blue must be equal, we ...”
November 14, 2018
Brent@GMATPrepNow posted a reply to How many positive two-digit numbers yield a remainder of 1 in the Problem Solving forum
“When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k are: 1, 1+5, 1+(2)(5), 1+(3)(5), ...”
November 14, 2018
GMATGuruNY posted a reply to On a wedding catering service, An experienced chef can in the Problem Solving forum
“Let service = 24 units. Rate for each experienced chef = w/t = 24/8 = 3 units per hour. Rate for each novice chef = w/t = 24/12 = 2 units per hour. Combined rate for 1 experienced chef and 1 novice chef working together = 3+2 = 5 units per hour. To produce 24 units in 1.6 hours, rate = w/t = ...”
November 13, 2018
GMATGuruNY posted a reply to Jake and Ryan worked together on a job for which they were in the Problem Solving forum
“Let the hourly wage = $1 per hour. Let Ryan''s time = 10 hours, implying that Jake''s time = 10 + (20% of 10) = 10 + 2 = 12 hours. Thus: Total number of work hours = 10+12 = 22 hours. Total pay = (hourly wage)(total number of work hours) = 1*22 =$22. Since the total pay = 10+12 = $22, and ...” November 13, 2018 Brent@GMATPrepNow posted a reply to When Leo imported a certain item, he paid a 7 percent import in the Problem Solving forum “Here''s a step-by-step algebraic solution. Let T = the TOTAL value of the item. Leo paid a 7% import tax on the portion of the total value of the item in EXCESS of$1000 So, Leo pays tax on the amount that''s GREATER then $1000 So, Leo pays 7% tax on (T - 1000) We can write: import tax = ...” November 13, 2018 Brent@GMATPrepNow posted a reply to If xy ≠ 0 and x^2+4y^2=4xy, (x+y)/(x-y)=? in the Problem Solving forum “GIVEN: x² + 4y² = 4xy Subtract 4xy from both sides to get: x² - 4xy + 4y² = 0 Factor left side to get: (x - 2y)(x - 2y) = 0 So, we can conclude that (x - 2y) = 0, which means x = 2y Now take (x+y)/(x-y) and replace x with 2y to get: (x + y)/(x - y) = (2y + y)/(2y - y) = 3y/y = 3 ...” November 13, 2018 GMATGuruNY posted a reply to A store purchased 20 coats that each cost an equal amount in the Data Sufficiency forum “Statement 1: If the selling price per coat had been twice as much , the store’s gross profit on the 20 coats would have been$2,400 When the selling price per coat is doubled, the resulting profit per coat = (total profit)/(number of coats) = 2400/20 = 120. Case 1: Double the selling price = ...”
November 13, 2018
GMATGuruNY posted a reply to If 60! is written out as an integer, with how many in the Problem Solving forum
“60! = 60*59*58*....*3*2*1. Since 10=2*5, EVERY COMBINATION OF 2*5 contained within the prime-factorization of 60! will yield a 0 at the end of the integer representation of 60!. The prime-factorization of 60! is composed of FAR MORE 2''S than 5''s. Thus, the number of 0''s depends on the ...”
November 13, 2018
GMATGuruNY posted a reply to In the figure AB and CD are two diameters of circle. in the Problem Solving forum
“An INSCRIBED ANGLE is formed by two chords. A CENTRAL ANGLE is formed by two radii. When an inscribed angle and a central angle intercept the same two points on a circle, the inscribed angle is 1/2 the central angle. https://i.postimg.cc/qgbxWKdW/Angle-CEB-1.png Here, inscribed angle CFB and ...”
November 12, 2018
Brent@GMATPrepNow posted a reply to OG #217 question in the Problem Solving forum
“P(selecting a sibling pair) = P(select a junior with a sibling AND select the senior who is that junior''s sibling) = P(select a junior with a sibling) x P(select the senior who is that junior''s siblingx 1/800 = 60/800,000 = 3/40,000 = A Note: P(select a junior with a sibling) = 60/1000, ...”
November 12, 2018
Brent@GMATPrepNow posted a reply to In the figure AB and CD are two diameters of circle. in the Problem Solving forum
“Let''s use some useful circle properties First let''s add a blue line, to divide ∠CEB into 2 angles https://i.imgur.com/xe05QIU.png CD is the DIAMETER of the circle Since ∠CED is an inscribed angle containing (aka "holding") the diameter, we can conclude that ∠CED = 90° ...”
November 12, 2018
Brent@GMATPrepNow posted a reply to Is the tallest child in Class A taller than tallest child in in the Data Sufficiency forum
“Target question: Is the tallest child in Class A is taller than tallest child in Class B? Jump to . . . Statements 1 and 2 COMBINED There are several scenarios that satisfy BOTH statements. Here are two: Case a: Class A heights = {1, 50} and Class B heights = {2, 40}. In this case, the ...”
November 12, 2018
Brent@GMATPrepNow posted a reply to Eight women and two men are available to serve on a in the Problem Solving forum
“When it comes to probability questions involving "at least," it''s best to try using the complement. That is, P(Event A happening) = 1 - P(Event A not happening) So, here we get: P(getting at least 1 man) = 1 - P(not getting at least 1 man) What does it mean to not get at least 1 man? ...”
November 11, 2018
Brent@GMATPrepNow posted a reply to If the positive integer n is greater than 6, what is the in the Data Sufficiency forum
“Here''s a somewhat long approach (but it works!): Target question: What is the remainder when n is divided by 6? Given: Positive integer n is greater than 6 Statement 1: When n is divided by 9, the remainder is 2. ------ASIDE---------------- When it comes to remainders, we have a ...”
November 11, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive integers, what is the remainder when in the Data Sufficiency forum
“Hi Swerve, To avoid ambiguity, you might want to add some spaces or brackets to the original expression. As it stands, 10^x+y could be interpreted as either 10^(x+y) or (10^x) + y Cheers, Brent”
November 11, 2018
GMATGuruNY posted a reply to If x and y are positive integers such that x = 8y + 12, what in the Data Sufficiency forum
“Statement 1: x=12u, where u is an integer and x=8y+12. In other words, x is a multiple of 12. For x to be a multiple of 12, 8y must be a multiple of 12. If y=3, then x = 8*3 + 12 = 36. The GCD of 3 and 36 is 3. If y=6, then x = 8*6 + 12 = 60. The GCD of 6 and 60 is 6. Since the ...”
November 11, 2018
GMATGuruNY posted a reply to Eight women and two men are available to serve on a in the Problem Solving forum
“P(at least 1 man) = 1 - P(no men). P(no men): P(1st person selected is a woman) = 8/10. (Of the 10 people, 8 are women.) P(2nd person selected is a woman) = 7/9. (Of the 9 remaining people, 7 are women.) P(3rd person selected is a woman) = 6/8. (Of the 8 remaining people, 6 are women.) To ...”
November 11, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive integers such that x = 8y + 12, what in the Data Sufficiency forum
“Target question: What is the greatest common divisor of x and y? Given: x = 8y + 12 Statement 1: x = 12u, where u is an integer. There are several pairs of values that satisfy the given conditions. Here are two: Case a: x=36 and y=3, in which case the GCD of x and y is 3 Case b: x=60 ...”
November 11, 2018
Brent@GMATPrepNow posted a reply to Which of the following is closest to the value of (2^23) in the Problem Solving forum
“(2^23)(5^26) = (2^23)(5^23)(5^3) = (2^23)(5^23)(5^3) = (10^23)(5^3) = (10^23)(125) ≈ (10^23)(100) ≈(10^23)(10^2) ≈10^25 Answer: C Cheers, Brent”
November 11, 2018
Brent@GMATPrepNow posted a reply to A gardener is going to plant 2 red rosebushes and 2 white in the Problem Solving forum
“We can also apply probability rules: P(2 middle bushes are red) = P(1st bush is white AND 2nd bush is red AND 3rd bush is red AND 4th bush is white) = P(1st bush is white) x P(2nd bush is red) x P(3rd bush is red) x P(4th bush is white) = 2/4 x 2/3 x 1/2 x 1/1 = 1/6 = B Cheers, Brent”
November 11, 2018
Brent@GMATPrepNow posted a reply to A gardener is going to plant 2 red rosebushes and 2 white in the Problem Solving forum
“As with many probability questions, we can also solve this using counting techniques. P(2 middle are red) = (# of outcomes with 2 red in middle)/(total number of outcomes) Label the 4 bushes as W1, W2, R1, R2 total number of outcomes We have 4 plants, so we can arrange them in 4! ways = ...”
November 11, 2018
GMATGuruNY posted a reply to A gardener is going to plant 2 red rosebushes and 2 white in the Problem Solving forum
“Moving LEFT TO RIGHT along the row: P(1st rosebush is white) = 2/4. (Of the 4 rosebushes, 2 are white.) P(2nd rosebush is red) = 2/3. (Of the 3 remaining rosebushes, 2 are red.) P(3rd rosebush is red) = 1/2. (Of the 2 remaining rosebushes, 1 is red.) P(4th rosebush is white) = 1/1. (The one ...”
November 10, 2018
Brent@GMATPrepNow posted a reply to Of the first three dozen cookies baked at a bake shop on a in the Data Sufficiency forum
“ Given: Of the first three dozen (36) cookies baked at a bake shop on a certain day, 1/3 were chocolate chip cookies. 1/2 of the remaining cookies that were baked that day were chocolate chip cookies, 1/3 of 36 = 12. So, 12 chocolate cookies were baked in the first round of baking. Let x = ...”
November 10, 2018
Brent@GMATPrepNow posted a reply to There were 36,000 hardback copies of a certain novel sold in the Problem Solving forum
“From the time the first paperback copy was sold until the last copy of the novel was sold 9 times as many paperback copies as hardback copies were sold Let x = number of hardback copies sold during this time So 9x = number of paperback copies sold during this time So, x + 9x = total number of ...”
November 10, 2018
Brent@GMATPrepNow posted a reply to A box contains 10 balls numbered from 1 to 10 inclusive. If in the Problem Solving forum
“P(Ann and Jane remove same ball) = P(Ann removes ANY ball AND Jane''s ball matches Ann''s ball) = P(Ann removes ANY ball) x P(Jane''s ball matches Ann''s ball) = 1 x 1/10 = 1/10 Answer: D Aside: Once Jane removes her ball (and then replaces it), we have 10 balls, and 1 of them is the one ...”
November 10, 2018
GMATGuruNY posted a reply to Every day at noon, a bus leaves for Townville and travels at in the Problem Solving forum
“Time and rate have a RECIPROCAL RELATIONSHIP: 2 times as fast implies 1/2 the time. 3 times as fast implies 1/3 the time. Let t = the normal time. Since the bus travels today at 7/6 its normal rate, the time today is equal to 6/7 of the normal time: (6/7)t. Since the bus leaves 1/2 hour late ...”
November 9, 2018
Brent@GMATPrepNow posted a reply to If CD = 6, what is the length of BC? in the Data Sufficiency forum
“Is there an image? Cheers, Brent”
November 9, 2018
Brent@GMATPrepNow posted a reply to Andrew has a certain number of coins in his pocket. He has in the Problem Solving forum
“Let x = number of QUARTERS in pocket So, 0.25x = VALUE of quarters in pocket He has three times as many dimes as quarters So, 3x = number of DIMES in pocket So, 0.10(3x) = 0.3x = VALUE of dimes in pocket He has six times as many nickels as dimes. So, (6)(3x) = number of NICKELS in ...”
November 8, 2018
Brent@GMATPrepNow posted a reply to Challenge: Al, Bob, Cal and Don each own 1 hat. If the 4... in the Problem Solving forum
“I created this question to highlight many students'' tendency to avoid listing and counting as a possible approach. As you''ll see, the approach is probably the fastest approach. P(no one receives his own hat) = (# of outcomes in which no one receives his own hat)/(TOTAL number of outcomes) ...”
November 8, 2018
Brent@GMATPrepNow posted a reply to There are 27 different three-digit integers that can be in the Problem Solving forum
“Yes, great work, Mitch! I thought I''d mention that, once we know the correct answer is a multiple of 222 (which is also a multiple of 3), then the correct answer will be a multiple of 3. Useful property: If a number is a multiple of 3, then the sum of its digits is also a multiple of 3. When we ...”
November 7, 2018
Brent@GMATPrepNow posted a new topic called Challenge: Al, Bob, Cal and Don each own 1 hat. If the 4... in the Problem Solving forum
“Al, Bob, Cal and Don each own 1 hat. If the 4 hats are randomly distributed so that each man receives exactly 1 hat, what is the probability that no one receives his own hat? A) 1/8 B) 1/4 C) 1/3 D) 3/8 E) 1/2 Answer: D Difficulty level: 650 – 700 Source: www.gmatprepnow.com”
November 7, 2018
Brent@GMATPrepNow posted a reply to If x, y and z are non-negative integers such that x < y & in the Problem Solving forum
“I created this question to show that there can be times when the best (i.e., fastest) way to solve a counting question is by listing and counting How do we know when it''s not a bad idea to use listing and counting? The answer choices will tell us (ALWAYS scan the answer choices before ...”
November 7, 2018
Brent@GMATPrepNow posted a reply to How many men are in a certain company's vanpool program? in the Data Sufficiency forum
“Target question: How many men are in a certain company''s vanpool program? Statement 1: The ratio of men to women in the program is 3 to 2. Let''s TEST some values. There are several scenarios that satisfy statement 1. Here are two: Case a: There are 3 men and 2 women in the program. In ...”
November 7, 2018
GMATGuruNY posted a reply to There are 27 different three-digit integers that can be in the Problem Solving forum
“Given any set that is symmetrical about the median: Sum = (quantity)(median) The set of 3-digit integers that can be formed from the digits 1,2 and 3 is symmetrical about the median (222): ...212, 213, 221, 222, 223, 231, 232... Thus: Sum of the 27 integers = (quantity)(median) = 27*222 = ...”
November 7, 2018
Brent@GMATPrepNow posted a reply to Speed Time Distance MGMAT in the Problem Solving forum
“GIVEN: When the men start walking, Brian has a 30-mile lead Let B = Brian''s walking speed (in miles per hour) Let A = Ashok''s walking speed (in miles per hour) Since Ashok''s speed is greater than Brian''s speed, the rate at which the gap shrinks = (A - B) miles per hour For example, if A ...”
November 6, 2018
Brent@GMATPrepNow posted a reply to 2019 GMAC Official Guide applicable for 60-Day Study Guide? in the The 60-Day GMAT Study Guide forum
“If you go here (https://www.gmatprepnow.com/content/improvement-chart) and download the Improvement Chart for the OG2016, you''ll see the question breakdown for each topic. This should help. Cheers, Brent”
November 6, 2018
Brent@GMATPrepNow posted a reply to In a certain game, a large bag is filled with blue, green, in the Problem Solving forum
“This question begs for some prime factorization. 88,000 = (2)(2)(2)(2)(2)(2)(5)(5)(5)(11) First, we can see that there must be one (11-point) red chip. Now, what role do these 2''s play? Since there are no 2''s hiding among the 5-point chips or the 11-point chips, the 2''s must be associated ...”
November 6, 2018
Brent@GMATPrepNow posted a reply to [x] is the greatest integer less than or equal x, what is th in the Problem Solving forum
“GIVEN: For example, [3.2] = 3, since 3 is the greatest integer that is less than (or equal) to 3.2 Likewise, [8.7] = 8, since 8 is the greatest integer that is less than (or equal to) 8.7 Now onto the question.... √25 = 5 √36 = 6 √49= 7 √64 = 8 Since √30 is BETWEEN √25 ...”
November 6, 2018
Brent@GMATPrepNow posted a reply to If in k+1 years from now John will be m years old, then how in the Problem Solving forum
“In k+1 years from now John will be m years old So, m - (k + 1) = John''s PRESENT age How old was John t-1 years ago? So, m - (k + 1) - (t - 1) = John''s age (t-1) YEARS AGO Simplify m - (k + 1) - (t - 1) to get: m - k - t Answer: A Cheers, Brent”
November 6, 2018
Brent@GMATPrepNow posted a reply to Pipe A runs 30 liters of water per minute into a pool that in the Problem Solving forum
“Let''s determine the COMBINED RATE of the two pipes Given: Pipe A''s RATE = 30 liters per minute This is equivalent to 1800 liters per HOUR Pipe B fills a third of the pool in 6 hours So, Pipe B fills the ENTIRE pool (3600 liters) in 18 hours Rate = Output/time = 3600/18 = 200 liters ...”
November 6, 2018
GMATGuruNY posted a reply to Is x^2>xy? in the Data Sufficiency forum
“For the purposes of a Y/N DS problem, the rephrase is the equivalent of the original question stem. Original question stem: Is x² > xy? The answer will be YES if y/x is less than 1.. The answer will be NO if y/x is NOT less than 1. Thus, the original question stem can be rephrased as ...”
November 5, 2018
Brent@GMATPrepNow posted a new topic called If x, y and z are non-negative integers such that x < y < z, in the Problem Solving forum
“If x, y and z are non-negative integers such that x < y < z, then the equation x + y + z = 11 has how many distinct solutions? A) 5 B) 10 C) 11 D) 22 E) 78 Answer: B Difficulty level: 600-650 Source: www.gmatprepnow.com”
November 5, 2018
Brent@GMATPrepNow posted a reply to Challenge question: Is |1 - 4k| < k? in the Data Sufficiency forum
“Target question: Is |1 - 4k| < k? Statement 1: k > 4x³ This pretty much tells is that k can have ANY value. For example, notice that, if x = -100, then 4x³ = -4,000,000 So, for this value of x, k can be any number greater than -4,000,000 Let''s TEST some values. There are ...”
November 5, 2018
Brent@GMATPrepNow posted a reply to Which sport utility vehicle has a higher list price, the in the Data Sufficiency forum
“Target question: Which sport utility vehicle has a higher list price, the Touristo of the Leisure? Statement 1: The list price of the Leisure is 5/6 the list price of the Touristo. If the Leisure''s price is 5/6 of the Touristo''s price, then the answer to the target question is the Touristo ...”
November 5, 2018
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Here''s our video on Range and Standard Deviation https://www.youtube.com/watch?v=FbAlIjw2fwY Cheers, Brent”
November 5, 2018
GMATGuruNY posted a reply to Is x^2>xy? in the Data Sufficiency forum
“x² > xy is true only if x is NONZERO, in which case we can safely divide by x², since the square of a nonzero value must be positive: x²/x² > (xy)/x² 1 > y/x Question stem, rephrased: Is y/x < 1? Statement 1: x > y If x=2 and y=1, then y/x =1/2. so the answer to the ...”
November 5, 2018
GMATGuruNY posted a reply to | 1 - | 2 - | 3 - | 4 – π | | | | in the Problem Solving forum
“Let π=3 in the original expression and simplify the blue portion below: | 1 - | 2 - | 3 - | 4 – 3 | | | | Simplify the red portion below; | 1 - | 2 - | 3 - 1 | | | Simplify the green portion below: | 1 - | 2 - 2 | | = | 1 - 0 | = 1 The correct answer choice must yield a value of ...”
November 5, 2018
Brent@GMATPrepNow posted a reply to If xy=-18, is x less than y? in the Data Sufficiency forum
“ Given: xy = -18 Target question: is x less than y? Statement 1: x < 0 In other words, x is NEGATIVE So, our given information (xy = -18) becomes: (NEGATIVE)(y) = -18 In other words: (NEGATIVE)(y) = NEGATIVE This tells us that y is POSITIVE If y is POSITIVE, and x is NEGATIVE, the ...”
November 4, 2018
GMATGuruNY posted a reply to Working alone, three persons P, Q, and R can do a certain in the Problem Solving forum
“Let the job = the LCM of the 3 times = 60 widgets. Maximum time: The maximum time is yielded when the slowest person -- R -- works alone. Since R takes 15 hours to complete the 60-widget job, the maximum time = 15 hours. Minimum time: The minimum time is yielded when all 3 people work ...”
November 4, 2018
GMATGuruNY posted a reply to Triplets Adam, Bruce, and Charlie enter a triathlon. If ther in the Problem Solving forum
“One approach: P(good outcome) = 1 - P(bad outcome). Bad outcome #1: Exactly 1 triplet wins. P(triplet wins 1st place) = 3/9. (Of the 9 competitors, 3 are triplets) P(non-triplet wins 2nd place) = 6/8. (Of the 8 remaining competitors, 6 are non-triplets) P(non-triplet wins 3rd place) = 5/7. ...”
November 4, 2018
Brent@GMATPrepNow posted a reply to Challenge #2: If x and y are different positive integers, wh in the Problem Solving forum
“i) When x is divided by y, the remainder is 2x The remainder cannot be greater than the dividend (the number we''re dividing) For example, it CANNOT be the case that 17 divided by 5 leaves a remainder of 34 Statement i can never be true Check the answer choices. . . . ELIMINATE A and D ii) ...”
November 3, 2018
Brent@GMATPrepNow posted a new topic called Challenge question: Is |1 - 4k| < k? in the Data Sufficiency forum
“Is |1 - 4k| < k? (1) k > 4x³ (2) k < 2x – x² - 2 Answer: B Difficulty level: 700+ Source: www.gmatprepnow.com”
November 3, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“Nicely done! Because the comparison in D allows for more than one logical interpretation, eliminate D. In fact, the ambiguity cited above is the most compelling reason to eliminate D.”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“X led to Y implies that X did not directly cause Y but that X was a factor that helped to yield Y. SC755 in the OG17: An inability to adapt led to their extinction. Here, an inability to adapt did not directly cause the extinction but was a factor that helped to yield the extinction. A cause ...”
November 2, 2018
Brent@GMATPrepNow posted a reply to If the average (arithmetic mean) of p, q, and r is 6, what i in the Data Sufficiency forum
“ Given: The average (arithmetic mean) of p, q, and r is 6 We can write: (p + q + r)/3 = 6 This means: p + q + r = 18 Target question: What is the value of r? Statement 1: p = -r Given: p + q + r = 18 Replace p with -r to get: -r + q + r = 18 Simplify: q = 18 What about the value of ...”
November 2, 2018
Brent@GMATPrepNow posted a reply to Cars J and K are making the trip from City A to City B. in the Problem Solving forum
“Car K travels at a constant speed that is 80% the constant speed of Car J Let''s assign some nice values to the speeds. Let''s say Car J travels 40 miles per hour So, Car K travels 32 miles per hour Car J departs from City A 15 minutes after Car K does Let''s calculate the distance that Car ...”
November 2, 2018
GMATGuruNY posted a reply to Ryunosuke Akutagawa in the Sentence Correction forum
“Generally, COMMA + as-clause implies that the clause after as LEADS to the preceding clause, with the result that the two clauses happen concurrently. An OA in GMATPrep: The steel industry has changed radically over the last two decades, as large, integrated companies such as Bethlehem Steel have ...”
November 2, 2018
GMATGuruNY posted a reply to Barry walks from one end to the other of a 30-meter long in the Problem Solving forum
“Let B = Barry''s rate and W = the walkway''s rate. The distance can be ANY VALUE. Let the distance = 240 meters. WITH the walkway, the time = 30 seconds: Here, Barry and the walkway WORK TOGETHER, so we ADD their rates: B+W = d/t = 240/30 = 8 meters per second. AGAINST the walkway, the ...”
November 2, 2018
Brent@GMATPrepNow posted a reply to At a family summer party, each of the x members of the in the Problem Solving forum
“Let''s use the INPUT-OUTPUT approach. It might be useful to choose a number that works well with the fractions given in the question (1/3 and 1/7). So, let''s say there are 21 family members at the party. In other words, we''re saying that x = 21 1/3 chose to have a hamburger, and of ...”
November 1, 2018
GMATGuruNY posted a reply to At a family summer party, each of the x members of the in the Problem Solving forum
“Let the x family members = the product of the two denominators = 3*7 = 21. Number who chose to have a hamburger = (1/3)(21) = 7. Since 1/7 of the hamburger-eaters also had a hot dog, the number who had both = (1/7)(7) = 1. Thus, the number who did NOT have both = (total members) - (number who had ...”
November 1, 2018
GMATGuruNY posted a reply to How many positive five-digit integers contain the digit in the Problem Solving forum
“I believe that the prompt above is outdated; regardless, it does not list a correct answer. The prompt below appears in Manhattan''s 5 lb. Book of GRE Practice Problems: Case 1: 57XXX Number of options for the hundreds digit = 10. (Any digit 0-9.) Number of options for the tens digit = 10. ...”
November 1, 2018
Brent@GMATPrepNow posted a reply to When a positive integer n is divided by 19, what is the rema in the Data Sufficiency forum
“Target question: When n is divided by 19, what is the remainder? Statement 1: n-17 is a multiple of 19 ----ASIDE------------------------------------------- If N is a multiple of d, then we can write N = dk (for some integer k) For example, if N is a multiple of 5, then we can write N = 5k ...”
November 1, 2018
Brent@GMATPrepNow posted a reply to In the diagram above, points A, B, C, D, and E represent the in the Problem Solving forum
“points A, B, C, D, and E represent the five teams in a certain league in which each team must play each of the other teams exactly once. Let''s first determine the total number of games that will be played. There are 5 teams, so each team will play 4 games (since a team can''t play itself) So, ...”
November 1, 2018
GMATGuruNY posted a reply to Two teachers, Ms. Ames and Mr. Betancourt, each had N in the Data Sufficiency forum
“Since the N cookies can be divided evenly among 24 or 18 students, N must be divisible by both 24 and 18. One way to determine the LCM of two integers is to take multiples of the LARGER integer until we get a multiple of the SMALLER integer. Multiples of 24: 24, 48, 72... We can stop here: the ...”
November 1, 2018
GMATGuruNY posted a reply to Did one of the 3 members of a certain team sell at least 2 in the Data Sufficiency forum
“Statement 1: If NONE of the members sells at least 2 tickets, then the 3 members sell a maximum of 1 ticket each, yielding the following total: 1+1+1 = 3. Too small, since the total number of tickets sold = 6. Implication: For a total of 6 tickets to be sold, one of the 3 members must sell at ...”
October 31, 2018
GMATGuruNY posted a reply to A football team averaged 35 points per game over the first in the Problem Solving forum
“This is a weighted average/mixture problem. Average score for the first N games = 35. Score for the final game = 28. Average score for the MIXTURE of all the games = 34. Step-by-step instruction for the alligation approach: Step 1: Plot the 3 averages on a number line, with the average ...”
October 31, 2018
Brent@GMATPrepNow posted a reply to In four years, Andy will be twice as old as Betsy. How old in the Data Sufficiency forum
“ Given: In four years, Andy will be twice as old as Betsy. Let A = Andy''s PRESENT age Let B = Betsy''s PRESENT age So, A+4 = Andy''s age IN 4 YEARS And so, B+4 = Betsy''s age IN 4 YEARS If Andy will be twice as old as Betsy IN 4 YEARS, we can write: A+4 = 2(B+4) Expand: A + 4 = 2B + 8 ...”
October 31, 2018
Brent@GMATPrepNow posted a reply to If m and n are integers, is m+m^2-n an even number? in the Data Sufficiency forum
“ Given: m and n are integers Target question: Is m + m² - n an even number? This is a good candidate for rephrasing the target question Aside: Here’s a video with tips on rephrasing the target question: We can take the expression, m + m² - n and rewrite it as m(1 + m) - n Now notice ...”
October 31, 2018
Brent@GMATPrepNow posted a reply to In 1995 a certain store had 1,800 tools in stock that had in the Problem Solving forum
“1,000 of these tools were sold in 1995 for $40 each So, the REVENUE = (1000)($40) = $40,000 The 1000 tools were purchased for$30 each. So, the EXPENSE = (1000)($30) =$30,000 PROFIT for 1995 = $40,000 -$30,000 = $10,000 ----------------------------------------------- The remaining 800 ...” October 31, 2018 GMATGuruNY posted a reply to 3, 6, 9, 12, … are multiples of 3. How many multiples of 3 in the Problem Solving forum “The difference between the endpoints of the range = 200-10 = 190. Since neither endpoint is a multiple of 3, we can count the multiples of 3 simply by dividing 3 into 190: 190/3 ≈ 63. The correct answer is D.” October 31, 2018 Brent@GMATPrepNow posted a reply to Tom, Bill, Robert, Roger, and Terry are standing in a row in the Problem Solving forum “One approach is to ignore the rule and determine the total number of ways to arrange all 5 people, and then subtract the number of arrangements that BREAK the rule. I''m sure someone will post that kind of solution shortly. Here''s another approach: Take the task of arranging the 5 men and ...” October 30, 2018 Brent@GMATPrepNow posted a new topic called Challenge #2: If x and y are different positive integers, wh in the Problem Solving forum “If x and y are different positive integers, which of the following COULD be true: i) When x is divided by y, the remainder is 2x ii) When x is divided by 2y, the remainder is y iii) When (2x + y) is divided by (x + y), the remainder is y A) i only B) ii only C) iii only D) i & ii ...” October 30, 2018 Brent@GMATPrepNow posted a reply to Challenge: If x and y are different positive integers, which in the Problem Solving forum “i) When x is divided by y, the remainder is x This occurs any time x < y For example, if x = 5 and y = 7, then statement i becomes: When 5 is divided by 7, the remainder is 5 So true! Scan the answer choices....eliminate D ----------------------------------------------------- ii) When 2x ...” October 30, 2018 Brent@GMATPrepNow posted a reply to Carmelo and LeBron participate in a seven-person footrace on in the Problem Solving forum “Here are three similar questions to practice with: - http://www.beatthegmat.com/counting-six-mobsters-t47167.html - http://www.beatthegmat.com/permutation-and-combination-t273916.html - http://www.beatthegmat.com/permutations-with-waiting-line-t274020.html Cheers, Brent” October 30, 2018 GMATGuruNY posted a reply to A group of 20 friends formed an investment club, with each in the Problem Solving forum “Let d=100. After the value of the stock increases by 40% to$140, the share received by each of the 20 friends = 140/20 = 7. The correct answer must yield a value of 7 when d=100. Only E works: (7d)/100 = (7*100)/100 = 7. The correct answer is E.”
October 30, 2018
Brent@GMATPrepNow posted a reply to A certain basket contains 10 apples, 7 of which are red and in the Problem Solving forum
“Jay has demonstrated a solution that involves counting techniques. Here''s one that involves probability rules. Let''s find the probability of selecting a red apple 1st, a red apple 2nd, and a green apple 3rd (aka RRG) P(red apple 1st AND red apple 2nd AND green apple 3rd) = P(red apple 1st) x ...”
October 30, 2018
Brent@GMATPrepNow posted a reply to A salesperson for an automobile dealer earns an annual in the Problem Solving forum
“Total earnings = (base salary) + (commission) base salary = $25,000 commission = 10% of total sales OVER$100,000 = 10% of (x - $100,000) = 0.1(x -$100,000) So, total earnings = $25,000 + 0.1(x -$100,000) Answer: E Cheers, Brent”
October 30, 2018
Brent@GMATPrepNow posted a reply to There are 16 teams in a soccer league, and team plays each in the Problem Solving forum
“Another approach: The question is really asking, "In how many different ways can we create 2-team pairings from 16 teams?" Since the order of the selections does not matter (i.e., selecting teams A and B to play, is the same as selecting teams B and A to play), we can use combinations. ...”
October 30, 2018
Brent@GMATPrepNow posted a reply to There are 16 teams in a soccer league, and team plays each in the Problem Solving forum
“There are 16 teams. If we ask each team, "How many teams did you play?" we''ll find that each team played 15 teams, which gives us a total of 240 games (since 16 x 15 = 240). From here we need to recognize that each game has been COUNTED TWICE. For example, if Team A and Team B play ...”
October 30, 2018
GMATGuruNY posted a reply to The average weight of a class is x pounds. When a new in the Problem Solving forum
“We can PLUG IN THE ANSWERS and use alligation. To learn about alligation, check my posts here: https://www.beatthegmat.com/statistics-average-question-t288903.html https://www.beatthegmat.com/alligation-method-t293459.html https://www.beatthegmat.com/mean-t266852.html Let O = the original ...”
October 30, 2018
GMATGuruNY posted a reply to Machines X and Y can work at their respective constant rates in the Data Sufficiency forum
“Statement 1: Time and rate have a RECIPROCAL relationship. Since X and Y together take 2/3 as long as Y alone, X and Y together work 3/2 as fast as Y alone. Thus, if Y''s rate alone = 2 units per hour, then X and Y''s combined rate = (3/2)(2) = 3 units per hour, implying that X''s rate alone = ...”
October 30, 2018
GMATGuruNY posted a reply to Set S contains nine distinct points in the coordinate plane. in the Problem Solving forum
“To form a triangle, we must select 3 points such that at most 2 are collinear. Case 1: Select 3 points not on the x-axis From the 4 points not on the x-axis, the number of ways to choose 3 = 4C3 = (4*3*2)/(3*2*1) = 4. Case 2: Select 1 point on the x-axis and two points not on the x-axis From ...”
October 29, 2018
Brent@GMATPrepNow posted a reply to For integers a, b, c, a/(b - c)=1 what is the value of (b-c) in the Data Sufficiency forum
“ Given: a/(b - c) = 1 Target question: What is the value of (b-c)/b ? This is a good candidate for rephrasing the target question. Aside: Here’s a video with tips on rephrasing the target question: If a/(b - c) = 1, then we know that a = b - c The target question asks "What is the ...”
October 29, 2018
Brent@GMATPrepNow posted a reply to If a and b are integers such that a > b > 1, which of in the Problem Solving forum
“Let''s make an important observation. Some positive multiples of 3 are: 3, 6, 9, 12, . . . . Some positive multiples of 5 are: 5, 10, 15, 20, . . . . Some positive multiples of 12 are: 12, 24, 36, 48, . . . . General observation: the positive multiples of k are all greater than or equal to k ...”
October 29, 2018
Brent@GMATPrepNow posted a new topic called Challenge: If x and y are different positive integers, which in the Problem Solving forum
“If x and y are different positive integers, which of the following COULD be true: i) When x is divided by y, the remainder is x ii) When 2x is divided by y, the remainder is x iii) When x+y is divided by x , the remainder is x-y A) i only B) i & ii only C) i & iii only D) ii & ...”
October 29, 2018
Brent@GMATPrepNow posted a reply to What is the value of x? in the Data Sufficiency forum
“Target question: What is the value of x? Statement 1: (x + 2)(x + 3) = 0 This means that EITHER x = -2 OR x = -3 Since we cannot answer the target question with certainty, statement 1 is NOT SUFFICIENT Statement 2: x² + 5x + 6 = 0 Factor the left side of the equation to get: (x + 2)(x ...”
October 29, 2018
GMATGuruNY posted a reply to Employees at a company will vote for an executive team of in the Problem Solving forum
“Number of options for president = 8. (Any of the 8 candidates.) Number of options for treasurer = 7. (Any of the 7 remaining candidates.) From the 6 remaining people, the number of ways to choose 3 to serve as warrant officers = 6C3 = (6*5*4)/(3*2*1) = 20. To combine these options, we multiply: ...”
October 29, 2018
GMATGuruNY posted a reply to A set of pencils can be evenly shared between 2, 3, 4, 5 and in the Problem Solving forum
“For the set of pencils to be shared evenly, the total number of pencils must be divisible by the total number of children. Thus, the correct answer must be divisible by 2, 3, 4, 5 and 6. Of the five answer choices, only E is divisible by 2, 3, 4, 5 and 6. The correct answer is E.”
October 29, 2018
GMATGuruNY posted a reply to (x^2-3x+2)(y^2-5y+6)=? in the Data Sufficiency forum
“Statement 1: Substituting x=1 into (x² - 3x + 2)(y² - 5x + 6), we get: (1 - 3*1 + 2)(y² - 5x + 6) = (0)(y² - 5x + 6) = 0. SUFFICIENT. Statement 2: Substituting y=1 into (x² - 3x + 2)(y² - 5x + 6), we get: (x² - 3x + 2)(1² - 5*1 + 6) = (x² - 3x + 2)(2). Since the value of x is ...”
October 29, 2018
Brent@GMATPrepNow posted a reply to A length of rope is cut into three different lengths. What in the Data Sufficiency forum
“Target question: What is the length of the shortest rope? Let''s assign some variables. Let x = length of shortest rope Let y = length of middle rope Let z = length of longest rope Statement 1: The combined length of the longest two pieces is 6 feet. In other words, y + z = 6 Since we ...”
October 28, 2018
Brent@GMATPrepNow posted a reply to Challenge question: At noon, Joe and a hummingbird leave in the Problem Solving forum
“The main idea here is that all 3 travelers travel for the SAME amount of time. So, let''s first determine the time it takes for Joe and Sue to meet. This is a shrinking gap question. To determine the rate at which the gap shrinks, we''ll ADD the travel speeds of Joe and Sue That is, ...”
October 28, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive, what is the value of y ? in the Data Sufficiency forum
“Target question: What is the value of y? Given: x and y are positive Statement 1: xy is the square of an integer. There are several values of x and y that satisfy this condition. Here are two: Case a: x = 1 and y = 1. Here xy = (1)(1) = 1, which is the square of an integer. In this ...”
October 28, 2018
GMATGuruNY posted a reply to How many integers are there between, but not including, in the Data Sufficiency forum
“Statement 1: Case 1: r=0 and s=10 Integers between r and s: 1, 2, 3, 4, 5, 6, 7, 8, 9 --> 9 integers Case 2: r=1 and s=11 Integers between r and s: 2, 3, 4, 5, 6, 7, 8, 9, 10 --> 9 integers Case 3: r=2 and s=12 Integers between r and s: 3, 4, 5, 6, 7, 8, 9, 10, 11 --> 9 ...”
October 28, 2018
GMATGuruNY posted a reply to Both Betty and Wilma earn annual salaries of more than $5000 in the Data Sufficiency forum “Statement 1: Betty''s annual salary is closer to$50000 than Wilma''s is. On a number line: -----50,000---B---W Thus, W > B. SUFFICIENT. Statement 2: Betty''s annual salary is closer to $35000 than it is to Wilma''s annual salary. Case 1: -----35,000-----50,000---B---W Case 2: ...” October 28, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: At noon, Joe and a hummingbird leave in the Problem Solving forum “At noon, Joe and a hummingbird leave point A and travel towards point B, which is 12 miles away. At the same time Sue leaves point B and travels toward point A. Joe, Sue and the hummingbird travel at constant speeds of 3 miles per hour, 4 miles per hour, and 84 miles per hour respectively. When the ...” October 27, 2018 Brent@GMATPrepNow posted a reply to There are n students in a class. Of them, k boys and k girls in the Data Sufficiency forum “Target question: What is the probability that Harvey will be paired with Jessica? Given: There are n students in a class. Of them, k boys and k girls (including Harvey and Jessica) are selected for a dance performance in which students will dance in pairs of one boy and one girl. ...” October 27, 2018 Brent@GMATPrepNow posted a reply to When the positive integer n is divided by 25, the remainder in the Data Sufficiency forum “Target question: What is the value of n? Given: When the positive integer n is divided by 25, the remainder is 13. -------ASIDE------------- When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, ...” October 27, 2018 Brent@GMATPrepNow posted a reply to A circus clown is entertaining kids by making balloon in the Problem Solving forum “As with many probability questions, we can solve this by using counting techniques or rules of probability. Let''s use rules of probability P(balloon animal is an elephant) = 1/4 P(balloon animal is purple) = 1/5 P(clown makes a purple elephant balloon animal) = P(balloon animal is ...” October 27, 2018 Brent@GMATPrepNow posted a reply to In a right triangle, the longer leg is two more than three in the Problem Solving forum “In a right triangle, the longest side is called the hypotenuse, and the two sides that meet to create a 90-degree angle are called the legs. So, one leg will be the triangle''s base, and the other leg will be the triangle''s height. Let x = length of the triangle''s base (which, for this ...” October 27, 2018 GMATGuruNY posted a reply to In a right triangle, the longer leg is two more than three in the Problem Solving forum “We can PLUG IN THE ANSWERS, which represent the length of the shorter leg. When the correct answer is plugged in, the area = 400. B: 20 Longer leg = two more than three times the shorter leg = 2 + 3*20 = 62. Area = (1/2)(20)(62) = 620. Since the area is too great, a smaller answer choice is ...” October 27, 2018 GMATGuruNY posted a reply to A framed picture is shown above. The frame, shown shaded, is in the Data Sufficiency forum “Statement 1: Test one case that also satisfies Statement 2. Case 1: The frame is 8 inches tall, with the result that the total area of the frame and picture combined = 6*8 = 48 Area of the picture = (total area) - (shaded region) = 48-24 = 24. Implication: The width of the frame is 1 inch, ...” October 27, 2018 Brent@GMATPrepNow posted a reply to If a and b are two positive numbers, what is the product of in the Data Sufficiency forum “Target question: What is the value of ab? Statement 1: The LCM of a and b is 16 Let''s TEST some values. There are several values of a and b that satisfy statement 1. Here are two: Case a: a = 1 and b = 16 (the LCM of 1 and 16 is 16). In this case, the answer to the target question is ab = ...” October 26, 2018 Brent@GMATPrepNow posted a reply to In the mid-1960's a newly installed radar warning system in the Sentence Correction forum “The idiom here is "Mistake x FOR y" So, we can eliminate A, C and E We''re left with B and D D conveys an ambiguous message, because it suggests that the moon was rising for an attack. ELIMINATE D Answer: B Cheers, Brent” October 26, 2018 GMATGuruNY posted a reply to What is the largest prime factor of the expression 3^8 − 2 in the Problem Solving forum “A general rule: Given x^(even power) - y^(even power), where x and y are distinct positive integers, we can always simplify by applying the difference of two squares. Each time we apply the difference of two squares to the expression in blue, the exponents are reduced by 1/2. For example: x⁸ - ...” October 26, 2018 Brent@GMATPrepNow posted a reply to What is the largest prime factor of the expression 3^8 − 2 in the Problem Solving forum “There''s a difference of squares "hiding" in the expression 3^8 − 2^12 That is 3^8 − 2^12 = (3^4)² − (2^6)² We know that: x² - y² = (x + y)(x - y) So, we get: (3^4)² − (2^6)² = (3^4 + 2^6)(3^4 - 2^6) = (81 + 64)(81 - 64) = (145)(17) = (5)(29)(17) The greatest ...” October 26, 2018 GMATGuruNY posted a reply to Jazz and blues recordings accounted for 6 percent of the in the Data Sufficiency forum “Let J = jazz and blues revenue in 1998. Statement 1: Case 1: Total revenue in 1998 = 100 In this case, J = 5% of 100 = 5. Case 2: Total revenue in 1998 = 1000 In this case, J = 5% of 1000 = 50. Since J can be different values, INSUFFICIENT. Statement 2: In other words: (jazz and blues ...” October 26, 2018 Brent@GMATPrepNow posted a reply to When Q is divided by W, the quotient is R and the remainder in the Problem Solving forum “-----ASIDE----------------------- There''s a nice rule that says, "If N divided by D equals Q with remainder R, then N = DQ + R" For example, since 17 divided by 5 equals 3 with remainder 2, then we can write 17 = (5)(3) + 2 Likewise, since 53 divided by 10 equals 5 with remainder 3, ...” October 26, 2018 GMATGuruNY posted a reply to x and y are non-negative integers. If xy+2x+3y=0, then y=? in the Problem Solving forum “NONNEGATIVE implies that we should test ZERO. Let x=0. Substituting x=0 into xy + 2x + 3y = 0, we get: 0*y + 2*0 + 3y = 0 3y = 0 y = 0 The correct answer is A.” October 26, 2018 GMATGuruNY posted a reply to Set S contains consecutive natural numbers from 1 to 100, in in the Problem Solving forum “For any evenly spaced set: sum = (count)(median) Sum of the first n even numbers = n * median of the first n even numbers Sum of the last n odd numbers = n * median of the last n odd numbers Since the ratio of the two sums = 16/85, we get: (n * median of the first n even numbers) / (n * ...” October 26, 2018 Brent@GMATPrepNow posted a reply to Tricky: If AB || DE, and AB = 10, what is the length of DE? in the Data Sufficiency forum “Let''s first add the given information (and their implications) to the diagram If AB || DE, we know that ∠BAC = ∠CED and ∠ABC = ∠DCE Also, since vertically opposite angles are equal, we know that ∠ACB = ∠DCE https://i.imgur.com/fgDp7Yh.png Now that we''ve identified 3 pairs of ...” October 26, 2018 Brent@GMATPrepNow posted a new topic called Tricky: If AB || DE, and AB = 10, what is the length of DE? in the Data Sufficiency forum “https://i.imgur.com/jyTAK6n.png If AB || DE, and AB = 10, what is the length of DE? (1) BC = 6 and CE = 4 (2) DC = 3 and CB = 6 Answer: B Difficulty level: 650 – 700 Source: www.gmatprepnow.com” October 25, 2018 Brent@GMATPrepNow posted a reply to If |x-6|=2x, then x=? in the Problem Solving forum “There are 3 steps to solving equations involving ABSOLUTE VALUE: 1. Apply the rule that says: If |x| = k, then x = k or x = -k 2. Solve the resulting equations 3. Plug solutions into original equation to check for extraneous roots Step 1: x - 6 = 2x or x - 6 = -2x case a: x - 6 = 2x Step ...” October 25, 2018 GMATGuruNY posted a reply to Quentin's income is 60% less than Rex's income, and Sam's in the Problem Solving forum “Let Rex''s income = 100. Since Quentin''s income is 60% less than Rex''s, Quentin''s income = 100 - (60% of 100) = 100-60 = 40. Since Sam''s income is 25% less than Quentin''s, Sam''s income = 40 - (25% of 40) = 40-10 = 30. After Rex gives 60% of his income to Sam, Sam''s new income = 30 + (60% ...” October 25, 2018 GMATGuruNY posted a reply to If |x-6|=2x, then x=? in the Problem Solving forum “We can PLUG IN THE ANSWERS, which represent the value of x. Since an absolute value cannot be equal to a negative value, the correct answer cannot be A or B. D: x=2 If we plug x=2 into |x-6|=2x, we get: |2-6| = 2*2 |-4| = 4 4 = 4. Success! The correct answer is D.” October 25, 2018 GMATGuruNY posted a reply to Tom drives from town A to town B, driving at a constant in the Problem Solving forum “Let the distance between A and B = 120 miles. Since the 120-mile distance between A and B is twice the distance between B and C, the distance between B and C = 60 miles, implying that the total distance = 120+60 = 180 miles. Since the average speed for the 120-mile leg between A and B = 60 mph, ...” October 25, 2018 GMATGuruNY posted a reply to gmat prep 2 in the Critical Reasoning forum “The negation test is not recommended for Evaluate CRs. It can be applied to Assumption CRs and Inference CRs.” October 24, 2018 GMATGuruNY posted a reply to Computer-based activities in the Critical Reasoning forum “The answer choices are already phrased as statements. The OA is a statement that weakens the conclusion. OA: Computer owners in the United States predominately belong to a demographic group that have long been known to spend less time watching television. This statement indicates that a lack of ...” October 24, 2018 GMATGuruNY posted a reply to Noelle walks from point A to point B at an average speed of in the Problem Solving forum “Let the distance between A and B = the LCM of the two speeds = 5*6 = 30 kilometers, implying that the distance for the entire round trip = 60 kilometers. At a rate of 5 kph, the time to travel the 30 kilometers from A to B = d/r = 30/5 = 6 hours. At a rate of 6 kph, the time to travel the entire ...” October 24, 2018 Brent@GMATPrepNow posted a reply to CHALLENGE: 10 teams (A, B, C, D, E, F, G, H, I and J) partic in the Problem Solving forum “First determine the TOTAL number of games played. We can select 2 teams from 10 teams in 10C2 ways (= 45 ways) So, there will be 45 games in TOTAL IMPORTANT: Each team plays 9 games For each game, 2 points are awarded. So, the TOTAL number of POINTS awarded = (2)(45) = 90 Teams A, B, C, ...” October 24, 2018 Brent@GMATPrepNow posted a reply to Noelle walks from point A to point B at an average speed of in the Problem Solving forum “For these kinds of questions, I typically follow the approach that Fabio used (assign a nice value to the distance). But we can also solve the question algebraically: Let d = the distance between Points A and B. Let x = the Noelle''s speed from Point B to Point A. We want the average ...” October 24, 2018 GMATGuruNY posted a reply to What is the median number of employees assigned per project in the Data Sufficiency forum “In ascending order of EMPLOYEES PER PROJECT, let the projects be numbered 1 through 100: 1, 2, 3.....49, 50, 51, ....98, 99, 100. Projects 50 and 51 determine the MEDIAN number of employees: Question rephrased: How many employees are assigned to PROJECTS 50 and 51? Looking at the two ...” October 24, 2018 Brent@GMATPrepNow posted a reply to What is the median number of employees assigned per project in the Data Sufficiency forum “Target question: What is the median number of employees assigned per project? Statement 1: 25 percent of the projects at Company Z have 4 or more employees assigned to each project. Let''s pretend that there are 4 projects altogether. There are several sets of values that meet this condition. ...” October 24, 2018 GMATGuruNY posted a reply to Three photographers , Lisa, Mike and Norm, take photos of a in the Problem Solving forum “The sum for Lisa and Mike is 50 less than the sum for Norm and Mike. Since Mike is common to both sums, the 50-photo difference must be yielded solely by Lisa and Norm. Implication: Lisa took 50 fewer photos than Norm. We can PLUG IN THE ANSWERS, which represent the number of photos taken by ...” October 24, 2018 GMATGuruNY posted a reply to Circle ABCD in the diagram above is defined by the equation in the Problem Solving forum “Circle ABCD: The equation for a circle with a center at the origin and a radius of r is x² + y² = r². The equation for circle ABCD is x² + y² = 5². Thus, circle ABCD has a radius of 5. Line EF: 3y = 4x + 25 y = (4/3)x + 25/3 Slope = 4/3. A radius drawn to a point of tangency forms ...” October 24, 2018 Brent@GMATPrepNow posted a reply to In a certain company, the ratio of the number of manager to in the Problem Solving forum “One option is to use TWO VARIABLES Let M = CURRENT # of managers Let W = CURRENT # of production-line workers The ratio of the number of managers to the number of production-line workers is 5 to 72. So, we can write: M/W = 5/72 Cross multiply to get: 5W = 72M If 8 additional ...” October 23, 2018 Brent@GMATPrepNow posted a reply to When 100 is divided by positive integer x, the remainder is in the Problem Solving forum “A fast approach is to find a value of x that meets the given condition: When 100 is divided by positive integer x, the remainder is 2 Well, x = 98 satisfies that condition, since 100 divided by 98 = 1 with remainder 2 What is the remainder when 198 is divided by x? Well, 198 divided by 98 ...” October 23, 2018 GMATGuruNY posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum “In many cases, similar or identical solutions are posted when two experts respond at virtually the same time, with the result that the second poster is not aware of the first. The time stamps for the two solutions here indicate that both solutions were posted at 11:45am.” October 23, 2018 GMATGuruNY posted a reply to A factory has three types of machines, each of which works in the Problem Solving forum “Rates can be ADDED TOGETHER. 7 Machine As and 11 Machine Bs can produce 250 widgets per hour. 7A + 11B = 250 8 Machine As and 22 Machine Cs can produce 600 widgets per hour. 8A + 22C = 600 4A + 11C = 300 Adding together 7A + 11B = 250 and 4A + 11C = 300, we get: 11A + 11B + 11C = 550 A ...” October 23, 2018 Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum “Range and Standard Deviation Video: https://www.youtube.com/watch?v=FbAlIjw2fwY Cheers, Brent” October 23, 2018 Brent@GMATPrepNow posted a reply to Which of the following values, when inserted into the set of in the Problem Solving forum “Let''s test each answer choice.... A. 2 The new set becomes {2, 5, 10, 12, 13, 17, 22, 22} Since we have an EVEN number of values in the set, the median equals the average of the two middlemost numbers. So, median = (12 + 13)/2 = 25/2 = 12.5 No good - we want the median to be 15 B. ...” October 23, 2018 Brent@GMATPrepNow posted a reply to What are the coordinates of point B in the figure above ? in the Data Sufficiency forum “IMPORTANT: For geometry Data Sufficiency questions, we are typically checking to see whether the statements "lock" a particular angle, length, or shape into having just one possible measurement. This concept is discussed in much greater detail in the video below. Target question: What ...” October 23, 2018 Brent@GMATPrepNow posted a reply to The range of set A is 24 and the range of set B is 20. What in the Problem Solving forum “If the range of set A is 24, and we add more values (from set B) to set A, then the range of the resulting set must be greater than or equal to 24 (that is, the range of a set cannot get smaller upon adding MORE numbers to that set). For this reason, we can ELIMINATE answer choice A. From ...” October 23, 2018 Brent@GMATPrepNow posted a reply to If x and y are positive integers, what is the remainder when in the Data Sufficiency forum “ Given: x and y are positive integers Target question: What is the remainder when x^y is divided by 10? This is a good candidate for rephrasing the target question. Notice that 43 divided by 10 leaves remainder 3, and 127 divided by 10 leaves remainder 7, and 618 divided by 10 leaves ...” October 23, 2018 GMATGuruNY posted a reply to 25 integers are written on a board. Are there at least two in the Data Sufficiency forum “The wording in Statement 1 does not convey a clear meaning: For every value in the list, if the value is increased by 1, the number of distinct values in the list does not change. Here, the term in red could convey to some test-takers that EVERY VALUE in the list is to be increased by 1. Not the ...” October 23, 2018 Brent@GMATPrepNow posted a new topic called CHALLENGE: 10 teams (A, B, C, D, E, F, G, H, I and J) partic in the Problem Solving forum “10 teams (A, B, C, D, E, F, G, H, I and J) participate in a soccer tournament in which each team plays every other team once. For each game played, points are awarded to the teams as follows: 0 points for losing the game 1 point each for tying the game 2 points for winning the game After ...” October 22, 2018 Brent@GMATPrepNow posted a reply to Clarissa will create her summer reading list by randomly in the Problem Solving forum “Take the task of creating the reading list and break it into stages. Stage 1: Select a book to read 1st There are 10 books to choose from. So, we can complete stage 1 in 10 ways Stage 2: Select a book to read 2nd There are 9 books remaining to choose from (since we already chose a book ...” October 22, 2018 Brent@GMATPrepNow posted a reply to A jar contains only green pencils and red pencils. If the in the Data Sufficiency forum “Target question: What percentage of the pencils are green? Given: The jar contains only green pencils and red pencils. Statement 1: The jar contains 75 red pencils. If 75 of the 225 pencils are red, then the remaining 150 pencils are GREEN. 150/225 = 2/3 = 66 2/3%, so the answer to ...” October 22, 2018 Brent@GMATPrepNow posted a reply to Challenge Question: In the x-y coordinate plane, does line k in the Data Sufficiency forum “Target question: Does line k have a positive x-intercept? Statement 1: (slope of line k)(y-intercept of line k) > 0 There are two possible cases that that satisfy statement 1: - the slope and y-intercept are both positive - the slope and y-intercept are both negative Let''s examine ...” October 21, 2018 Brent@GMATPrepNow posted a reply to What is the area of the triangle formed by the intersection in the Problem Solving forum “Here''s a similar question to practice with: https://www.beatthegmat.com/area-of-triangle-formed-by-intersections-of-3-lines-t276079.html Cheers, Brent” October 21, 2018 GMATGuruNY posted a reply to The annual rent collected by a corporation from a certain in the Data Sufficiency forum “Let the 1997 rent = 100. Increase in 1998 = (x/100)(100) = x. Thus, rent in 1998 = 100+x. Decrease in 1999 = (y/100)(100+x) = y + xy/100 For the rent to be greater in 1999 than in 1997, the increase in 1998 (x) must be greater than the decrease in 1999 (y + xy/100). Question stem, ...” October 21, 2018 GMATGuruNY posted a reply to During a 3 year period, the profits of company X changed by in the Data Sufficiency forum “Statement 1: If profits increase by$X from the first year to the second year, then they must increase by $0 from the second year to the third year, with the result that the increase in profits from the first year to the third year (X+0 =$X) is the same as the increase in profits from the first ...”
October 21, 2018
GMATGuruNY posted a reply to OG The estimated number of homeschooled students in the Problem Solving forum
“Percent greater or percent increase: (bigger value - smaller value)/(smaller value) * 100 Percent less or percent decrease: (bigger value - smaller value)/(bigger value) * 100”
October 21, 2018
GMATGuruNY posted a reply to Mark has fewer than 9 coins. Each coin is either a quarter in the Data Sufficiency forum
“Statement 1: 25Q + 10D = 170 5Q + 2D = 34 To minimize the number of coins, we must maximize the value of Q. If Q=6, then D=2, with the result that 5Q + 2D = (5*6) + (2*2) = 34. In this case, the total number of coins = 6+2 = 8. If the value of Q decreases, then the total number of coins will ...”
October 20, 2018
GMATGuruNY posted a reply to doubt 3 in the Sentence Correction forum
“having + VERBed is a viable construction. An introductory HAVING + VERBed modifier implies PRIOR ACTION: an action completed before the main verb. HAVING FINISHED his dessert, John LEFT the table. Here, HAVING FINISHED implies PRIOR ACTION -- an action completed before John LEFT the table. ...”
October 20, 2018
GMATGuruNY posted a reply to All attendees at a university gathering are faculty or in the Data Sufficiency forum
“Neither statement offers any information about the number of attendees who are alumni. Thus, the two statements combined are INSUFFICIENT. The correct answer is E.”
October 20, 2018
GMATGuruNY posted a reply to If n is an integer, which of the following must be divisible in the Problem Solving forum
“Test n=0. A --> n³ - 4n = 0³ - (4*0) = 0 B --> n³ + 4n = 0³ + (4*0) = 0 C --> n² + 1 = 0² + 1 = 1 D --> n² - 1 = 0² - 1 = -1 E --> n² - 4 = 0² - 4 = -4 Only the options in green yield a multiple of 3. Eliminate C, D and E. Test n=1 in the remaining answer ...”
October 20, 2018
GMATGuruNY posted a reply to At a certain industrial manufacturer, an open tank contains in the Problem Solving forum
“Since 6% of the 1000-gallon tank is fluorine, the amount of fluorine = (6/100)(1000) = 60 gallons. Since the total volume decreases at a rate of 10 gallons per day for 25 days, the decrease in the total volume = 10*25 = 250 gallons. Remaining total volume = 1000-250 = 750 gallons. Since 60 of the ...”
October 20, 2018
GMATGuruNY posted a reply to Is 1+x+x^2+x^3+x^4+x^5+x^6 < 1/(1-x)? in the Data Sufficiency forum
“CRITICAL POINTS in an equality occur when the two sides are EQUAL or the inequality is undefined. Here, the two statements provide the critical points for the inequality in the prompt: When x=0, the two sides are equal. When x=1, the inequality is undefined. To determine the range(s) where the ...”
October 20, 2018
Brent@GMATPrepNow posted a new topic called Challenge Question: In the x-y coordinate plane, does line k in the Data Sufficiency forum
“In the x-y coordinate plane, does line k have a positive x-intercept? (1) (slope of line k)(y-intercept of line k) > 0 (2) (slope of line k) - (y-intercept of line k) < 0 Answer: A Difficulty level: 650 – 700 Source: www.gmatprepnow.com”
October 19, 2018
Brent@GMATPrepNow posted a reply to When positive integer N is divided by positive integer J, in the Problem Solving forum
“ASIDE: 7/2 = 3 1/2 = 3 + 0.5 = 3.5 Notice that 1 is the remainder when we divide 7 by 2. 23/5 = 4 3/5 = 4 + 0.6 = 4.6 Notice that 3 is the remainder when we divide 23 by 5. 31/4 = 7 3/4 = 7 + 0.75 = 7.75 Notice that 3 is the remainder when we divide 31 by 4. GIVEN: N/J = 134.08 This means ...”
October 19, 2018
GMATGuruNY posted a reply to Did Jeff record more sales revenue this month than Dan did? in the Data Sufficiency forum
“Statement 1: For every $100 commission that Dan earns, Jeff earns$120 in commission. Since the commission rates for Dan and Jeff are unknown, no way to determine whether Jeff recorded more sales revenue than Dan. INSUFFICIENT. Statement 2: Since Jeff''s sales and Dan''s sales can be any ...”
October 19, 2018
Brent@GMATPrepNow posted a reply to If there are more than two numbers in a certain list, is in the Data Sufficiency forum
“[quote="Jay@ManhattanReview"] Hey Jay, I thought I should point out that case 2 doesn''t satisfy the statement. If we choose 1 and 2 from the set, then the product isn''t 0. That said, {0, 0, 0, 0, 1} meets the given condition, as does {0, 0, 0, 0, 0, 0, 0, 3} etc Cheers, ...”
October 19, 2018
Brent@GMATPrepNow posted a reply to If -1<x<0, Which of the following is listed in ascendi in the Problem Solving forum
“Let''s test a value of x. If -1 < x < 0, then x COULD equal -1/2 So, x^(-1) = (-1/2)^(-1) = 1/(-1/2) = -2 And, x^(-2) = (-1/2)^(-2) = 1/(-1/2)^2 = 1/(1/4) = 4 And, x^2 = (-1/2)^2 = 1/4 Listed in ascending order, we get: -2, 1/4, 4 In other words, x^(-1), x^2, x^(-2) Answer: A ...”
October 19, 2018
GMATGuruNY posted a reply to If a rectangle’s length is a+b and its area is (1/a)+(1/b) in the Problem Solving forum
“Let a=b=0.5, implying that the rectangle''s length = a+b = 0.5+0.5 = 1 and that its area = (1/0.5) + (1/0.5) = (10/5) + (10/5) = 2+2 = 4. Since the rectangle has an area of 4 and a length of 1, its width = 4. The correct answer must yield a value of 4 when a=b=0.5. Only E works: 1/ab = 1/(0.5 * ...”
October 19, 2018
GMATGuruNY posted a reply to When positive integer N is divided by positive integer J, in the Problem Solving forum
“N/J = 134.08 = 13408/100 = 3352/25. The resulting ratio indicates that N must be multiple of 3352 and that J must be a multiple of 25. Of the five answer choices, only E is a multiple of 25. The correct answer is E.”
October 19, 2018
GMATGuruNY posted a reply to A container contains 4 red marbles and 8 blue marbles. in the Problem Solving forum
“We can PLUG IN THE ANSWERS, which represent the number of blue marbles in the second container. When the correct answer is plugged in, the probability of selecting 2 red marbles OR 2 blue marbles = 1/2. B: 4 blue marbles, implying a total of 10 marbles in the second container Case1: 2 red ...”
October 19, 2018
GMATGuruNY posted a reply to Two printing presses begin printing currency at the same in the Problem Solving forum
“Since F produces 1000 5-dollar bills each minute, the dollar amount produced by F each minute = 1000*5 = $5000. Since T produces 200 20-dollar bills each minute, the dollar amount produced by T each minute = 200*20 =$4000. Thus, every minute F surpasses T by $1000. Since F surpasses T by$1000 ...”
October 18, 2018
Brent@GMATPrepNow posted a reply to The latest model of space shuttle can achieve a maximum in the Problem Solving forum
“GIVEN: The shuttle can travel 25 miles in 1 second So, the shuttle can travel 1500 miles in 60 seconds In other words, the shuttle can travel 1500 miles in 1 MINUTE So, the shuttle can travel 90,000 miles in 60 MINUTES In other words, the shuttle can travel 90,000 miles in 1 HOUR In other ...”
October 18, 2018
Brent@GMATPrepNow posted a reply to A jar contains 6 red marbles and 9 blue marbles. If Evelyn in the Problem Solving forum
“P(both are same color) = P(1st marble is red AND 2nd marble is red OR 1st marble is blue AND 2nd marble is blue) = x P(2nd marble is red)] + x P(2nd marble is blue)] = x 5/14] + x 8/14] = x 5/14] + x 8/14] = 10/70 + 24/70 = 34/70 = 17/35 Answer: D Cheers, Brent”
October 18, 2018
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Time management strategy for test day Video: https://www.youtube.com/watch?v=bWrUiBT83PQ Cheers, Brent”
October 18, 2018
Brent@GMATPrepNow posted a reply to In the x-y coordinate plane, line k passes through in the Problem Solving forum
“Notice that, if the line passes through the origin, then the line has slope -4/5 (aka a slope of -0.8), but the line will not have a negative x-intercept Notice that, if the line passes through the (0,4), then the line will have slope 0, BUT the line will not have a negative x-intercept. See ...”
October 18, 2018
GMATGuruNY posted a reply to Brian purchased a bouquet of 40 flowers for his mother for in the Problem Solving forum
“= We can PLUG IN THE ANSWERS, which represent the number of tulips. When the correct answer is plugged in, the total cost = $48. D: 24 tulips, implying 16 roses, for a total of 40 flowers Since each of the 24 tulips costs$1, and each of the 16 roses costs $1.50, we get: Total cost = (24*1) ...” October 18, 2018 Brent@GMATPrepNow posted a reply to f[f{f(x)}]=??? in the GMAT Math forum “Useful property: 1/(a/b) = b/a We want: ff(5)}] = f1/6}] f{1/6} = 1/(1 + 1/6) = 1/(7/6) = 6/7 So, ff{1/6}] = f6/7] Finally, f[6/7] = 1/(1 + 6/7) = 1/(13/7) = 7/13 Answer: B (since 21/39 reduces to the equivalent fraction 7/13) Cheers, Brent” October 18, 2018 Brent@GMATPrepNow posted a reply to In the month of August, Pentheus Corporation made$200,000 in the Problem Solving forum
“In the month of August, Pentheus Corporation made $200,000 in profit. Pentheus made 6% of that profit on the second Wednesday of August. 1% of$200,000 = $2,000, so 6% of$200,000 = (6)($2,000) =$12,000 So, the profit on that day = $12,000 If the profits that day were approximately 14.5% of ...” October 18, 2018 Brent@GMATPrepNow posted a reply to Brian purchased a bouquet of 40 flowers for his mother for in the Problem Solving forum “We can solve this question using either 1 variable or 2 variables. Here''s an approach that involves 1 variable: Let t = # of tulips in bouquet So. 40 - t = # of roses in bouquet So, ($1.00)(t) = the total COST of all t tulips And ($1.50)(40 - t) = the total COST of all 40-t roses ...” October 18, 2018 Brent@GMATPrepNow posted a reply to In a town of 8,000 residents, 65 percent of all residents in the Problem Solving forum “Another approach is to use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of residents, and the two characteristics are: ...” October 17, 2018 Brent@GMATPrepNow posted a reply to What is the remainder if 7^10 is divided by 100? in the Problem Solving forum “Sweeeeeeeeeeeeet solution, Scott!! Cheers, Brent” October 17, 2018 Brent@GMATPrepNow posted a reply to If x, y, and z are all nonzero numbers, and x = y + z, which in the Problem Solving forum “NOTE: this is one of those questions that require us to check/test each answer choice. In these situations, always check the answer choices from E to A, because the correct answer is typically closer to the bottom than to the top. For more on this strategy, see my article: ...” October 16, 2018 Brent@GMATPrepNow posted a reply to Set X consists of different positive numbers arranged in in the Data Sufficiency forum “Target question: What is the arithmetic mean of set X? Given: Set X consists of different positive numbers arranged in ascending order: K, L, M, 5, 7. K, L and M are consecutive integers This means that EITHER K, L, M = 1, 2, 3 respectively, OR K, L, M = 2, 3, 4 respectively Head straight ...” October 16, 2018 Brent@GMATPrepNow posted a reply to A Martian bat flies at 60 yards per second from its nest to in the Problem Solving forum “Rich''s approach is definitely the best (i.e., fastest) way to solve this question. However, if the answer choices weren''t so sweet, here''s an algebraic solution Average speed = (total distance traveled)/(total travel time) Let''s assign nice values to the distances. These values should ...” October 16, 2018 GMATGuruNY posted a reply to A certain NYC taxi driver has decided to start charging a in the Problem Solving forum “Let r=100 cents. For 3 people, the cost per mile = 3*100 = 300 cents = 3 dollars. Let x = 2 miles. Regular cost for 3 people to travel 2 miles = 3*2 = 6 dollars. With a 50% discount, the cost in dollars = 3. This is the target. Plug x=2 and r=100 into the answers to see which yields the ...” October 16, 2018 Brent@GMATPrepNow posted a reply to Charlie takes 2.5 hours to fly from Los Angeles to Mexico in the Problem Solving forum “Average speed = (total distance traveled)/(total travel time) So, Average speed = 1200/2.5 = 2400/5 = 4800/10 = 480 mph Answer: D Cheers, Brent” October 16, 2018 Brent@GMATPrepNow posted a reply to A certain NYC taxi driver has decided to start charging a in the Problem Solving forum “Here''s an algebraic approach: A certain taxi driver charges a rate of r CENTS per person per mile r CENTS = r/100 DOLLARS Since there are 3 people, the rate is (3)(r/100) DOLLARS per mile In other words, the rate is 3r/100 dollars per mile. With a 50% discount, the new rate = ...” October 16, 2018 Brent@GMATPrepNow posted a new topic called In the x-y coordinate plane, line k passes through in the Problem Solving forum “In the x-y coordinate plane, line k passes through the point (5, -4) and has a negative x-intercept. Which of the following COULD be the equation of line k? i) y = -0.4x - 2 ii) y = 2 - 1.2x iii) y = -0.7x - 1.5 A) i only B) ii only C) iii only D) i & ii only E) i & iii only ...” October 16, 2018 GMATGuruNY posted a reply to (1-1/10)(1-1/11)(1-1/12)…(1-1/100) =? in the Problem Solving forum “(1-1/10)(1-1/11)(1-1/12)…(1-1/99)(1-1/100) = (9/10)(10/11)(11/12)....(98/99)(99/100). The values in blue all cancel out, leaving only the values in red: 9/100. The correct answer is C.” October 16, 2018 GMATGuruNY posted a reply to A rectangular garden is to be twice as long as it is wide. in the Problem Solving forum “We can PLUG IN THE ANSWERS, which represent the length. When the correct answer is plugged in, perimeter = 360. B: 140 Since the length is twice the width, W = 70, with the result that the perimeter = 140+140+70+70 = 420. Since the perimeter is too great, a SMALLER answer choice is needed. ...” October 16, 2018 GMATGuruNY posted a reply to Is the sum of 7 different positive integers greater than or in the Data Sufficiency forum “Statement 1: Least possible case: 1+2+3+9+10+11+12 = 48. Since the least possible case is greater than or equal to 48, the answer to the question stem is YES. SUFFICIENT. Statement 2: Least possible case: 1+2+3+4+5+6+12 = 33. Greatest possible case: 6+7+8+9+10+11+12 = 63. Since the answer ...” October 16, 2018 GMATGuruNY posted a reply to If x, y, and z are all nonzero numbers, and x = y + z, which in the Problem Solving forum “x = y + z is valid if x=2, y=1 and z=1. The correct answer must yield a value of 1 when x=2, y=1 and z=1. Only E works: (x-z)/y = (2-1)/1 = 1. The correct answer is E.” October 16, 2018 GMATGuruNY posted a reply to If |x+1|=2|x-1|, x=? in the Data Sufficiency forum “Case 1: Signs unchanged x+1 = 2(x-1) x+1 = 2x-2 3 = x Case 2: Signs changed on ONE SIDE -x-1 = 2(x-1) -x-1 = 2x-2 1 = 3x 1/3 = x Resulting solutions: x=3 or x=1/3 Statement 1: Since x < 1, only x=1/3 is a viable solution. SUFFICIENT. Statement 2: Since x>0, both x=1/3 ...” October 15, 2018 Brent@GMATPrepNow posted a reply to Lindsay can paint 1/x of a certain room in one hour. If in the Problem Solving forum “This appears to be a slightly different version of this official question: https://www.beatthegmat.com/work-rate-problem-5-t292679.html HOWEVER, unless I''m missing something, the correct answer is missing. Cheers, Brent” October 15, 2018 GMATGuruNY posted a reply to Lindsay can paint 1/x of a certain room in one hour. If in the Problem Solving forum “Let the room = 20 units. Let x = 4. Since Lindsay paints 1/x of the room in 1 hour, Lindsay''s rate = (1/4) * 20 = 5 units per hour. Since Lindsay and Joseph paint the entire room in 1 hour, their combined rate = 20 units per hour. Thus, Joseph''s rate = (combined rate) - (Lindsay''s rate) ...” October 15, 2018 Brent@GMATPrepNow posted a reply to How many factors does the number X have? in the Data Sufficiency forum “Target question: How many factors does the number X have? Statement 1: X is divisible by 47 Let''s TEST some values. There are several values of X that satisfy statement 1. Here are two: Case a: X = 47. The factors of 47 are {1, 47}. So, the answer to the target question is X has 2 ...” October 15, 2018 GMATGuruNY posted a reply to The principal feature of the redesigned checks is a series o in the Sentence Correction forum “Generally, a COMMA + VERBing modifier serves to modify the nearest preceding action and the agent of this action. C: instructions that...will help merchants confirm a check''s authenticity, by including reminders to watch the endorsement. .Here, COMMA + by including seems to modify merchants ...” October 15, 2018 Brent@GMATPrepNow posted a reply to A rectangular solid S, has dimensions 4 by 9 by k. What is in the Data Sufficiency forum “Target question: What is the value of k? Given: A rectangular solid S, has dimensions 4 by 9 by k Statement 1: 4 < k < 9 Since k can have ANY value between 4 and 9, statement 1 is NOT SUFFICIENT Statement 2: A cube of side 6 has the same volume as rectangular solid S. So ...” October 15, 2018 Brent@GMATPrepNow posted a reply to In the rectangular coordinate system above, if the in the Data Sufficiency forum “I think that, if this were an official GMAT question, the correct answer would be E (not B), because we aren''t specifically told that the dotted lines are parallel to the x-axis and the y-axis. If those dotted lines aren''t parallel to those axes, the we can''t determine the value of y. ...” October 15, 2018 Brent@GMATPrepNow posted a reply to In the figure above, triangle ABC is equilateral, and point in the Problem Solving forum “It may help to add some lines to the diagram. First add lines from the center to the 3 vertices. https://s8.postimg.cc/e412m8uq9/clk1.jpg Aside, we know that each angle is 120º since all three (equivalent) angles must add to 360.º Then draw a circle so that the triangles vertices are on ...” October 15, 2018 GMATGuruNY posted a reply to What is the remainder if 7^10 is divided by 100? in the Problem Solving forum “When a positive integer is divided by 100, the remainder is yielded by the last two digits: 123/100 = 1 R23 548/100 = 5 R48 692/100 = 6 R92 Thus: The remainder when 7¹⁰ is divided by 100 is equal to the last two digits of 7¹⁰. Calculate the last two digits for consecutive powers of 7 ...” October 14, 2018 Brent@GMATPrepNow posted a reply to The mass of 1 cubic meter of a substance is 800 kg under in the Problem Solving forum “GIVEN: 1 cubic METER of the substance weighs 800 KILOGRAMS 1 kg =1,000 grams, so we can write: 1 cubic METER of the substance weighs 800,000 GRAMS 1 cubic meter = 1,000,000, so we can write: 1,000,000 cubic CENTIMETERS of the substance weighs 800,000 GRAMS What is the volume in cubic ...” October 14, 2018 Brent@GMATPrepNow posted a reply to At a family summer party, each of the x members of the in the Problem Solving forum “These kinds of questions (Variables in the Answer Choices - VIACs) can be answered algebraically or using the INPUT-OUTPUT approach. The Ash Mo solved the question algebraically, so let''s use the INPUT-OUTPUT approach. It might be useful to choose a number that works well with the fractions ...” October 13, 2018 Brent@GMATPrepNow posted a reply to When A and B are positive integers, is AB a multiple of 4? in the Data Sufficiency forum “Target question: Is AB a multiple of 4? Useful property: If N is divisible by d, we can say that N = dk for some integer k For example, if N is divisible by 5, we can say that N = 5k for some integer k Statement 1: The greatest common divisor of A and B is 6 This means that A is divisible ...” October 13, 2018 Brent@GMATPrepNow posted a reply to How much time did it take a certain car to travel 400 in the Data Sufficiency forum “Target question: How long did it take to travel 400km To find the travel time, we need to know the average speed traveled. Let x = the average speed traveled. REPHRASED target question: What is the value of x? Statement 1: The car traveled the first 200 km in 2.5 hrs No info about the ...” October 13, 2018 Brent@GMATPrepNow posted a reply to Challenge question: What is the sum of all in the Problem Solving forum “Approach #1 If we recognize that x^(2/3) = u-substitution. Let u = x^(1/3) Now take original equation and replace x^(1/3) with u to get: u² - u - 2 = 4 Subtract 4 from both sides to get: to get: u² - u - 6 = 0 Factor: (u - 3)(u + 2) = 0 So, the two solutions here are u = 3 and u = -2 ...” October 13, 2018 GMATGuruNY posted a reply to Alice, Barbara, and Cynia work on identical tasks at differe in the Data Sufficiency forum “TIME and RATE have a reciprocal relationship. Statement 1: The time ratio for Barbara and Alice = (14 hours)/(21 hours). The rate ratio for Barbara and Alice is equal to the reciprocal of the time ratio: (B''s rate)/(A''s rate) = 21/14 = 3/2. Let B = 3 units per hour and A = 2 units per ...” October 13, 2018 Brent@GMATPrepNow posted a reply to A certain club has 10 members, including Harry. One of the 1 in the Problem Solving forum “As with many probability questions, we can solve this using counting techniques or probability rules. So, before you embark on one approach, try to determine which one is faster. Here''s the probability approach: P(Harry selected Secretary or Treasurer) = 1 - P(Harry selected president OR ...” October 13, 2018 GMATGuruNY posted a reply to James started from his home and drove eastwards at a in the Problem Solving forum “Let James'' rate = 3 mph. James started from his home and drove eastwards at a constant speed. Exactly 90 minutes after James stated from his home, his brother Patrick started from the same point and drove in the same direction as James did at a different constant speed. Patrick overtook James ...” October 13, 2018 GMATGuruNY posted a reply to A certain club has 10 members, including Harry. One of the 1 in the Problem Solving forum “Each of the 10 members has an EQUAL chance of being elected secretary. P(Harry is elected secretary) = 1/10. Each of the 10 members has an EQUAL chance of being elected treasurer. P(Harry is elected treasurer) = 1/10. Since EITHER outcome is favorable, we ADD the fractions: 1/10 + 1/10 = 2/10 = ...” October 13, 2018 Brent@GMATPrepNow posted a reply to The average age of a group of n people is 15 yrs. One more in the Problem Solving forum “The average age of a group of n people is 15 yrs. So, (sum of all n ages)/n = 15 Multiply both sides by n to get: (sum of all n ages) = 15n One more person aged 39 joins the group and the new average is 17 yrs. IMPORTANT: Once this 39-year-old is added to the group, the (NEW sum of ages) = ...” October 12, 2018 GMATGuruNY posted a reply to Challenge question: What is the sum of all in the Problem Solving forum “x^(2/3) - x^(1/3) - 2 = 4 x^(2/3) - x^(1/3) - 6 = 0 D.” October 12, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: What is the sum of all in the Problem Solving forum “What is the sum of all solutions to the equation x^(2/3) - x^(1/3) - 2 = 4? A) -35 B) -19 C) 7 D) 19 E) 35 Answer: D Source: www.gmatprepnow.com Difficulty level: 600 - 650” October 12, 2018 October 12, 2018 Brent@GMATPrepNow posted a reply to Challenge question: j and k are positive integers in the Data Sufficiency forum “ Given: n = 10^j + k Target question: Is n divisible by 15? Key concepts: - If n is divisible by 15, then n must be divisible by 3 AND by 5 - If n is divisible by 3, then the sum of n''s digits must be divisible by 3 (for example, we know that 747 is divisible by 3, because 7+4+7 = 18, ...” October 12, 2018 GMATGuruNY posted a reply to Hard Assumption - Manhattan in the Critical Reasoning forum “The conclusion is constrained to the case at hand: Of the 10 babies recently placed with parents, 8 were given to friends of the staff. The assumption is that the premise (the parents given babies -- including the 8 friends --all far surpassed the agency''s criteria) is sufficient to prove the ...” October 11, 2018 Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum “Here''s our video on "if" versus "whether" https://www.youtube.com/watch?v=F2ZHtB088us Cheers, Brent” October 11, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: j and k are positive integers in the Data Sufficiency forum “j and k are positive integers, and n = 10^j + k. Is n divisible by 15? (1) j and k are each divisible by 3 (2) j and k are each divisible by 5 Answer: A Difficulty level: 700+ Source: www.gmatprepnow.com” October 11, 2018 GMATGuruNY posted a reply to If every boy in a kindergarten class buys a soda and every in the Problem Solving forum “Let: b = the number of boys g = the number of girls s = the number of cents for each soda j = the number of cents for each juice box Note: All of the values above must be POSITIVE INTEGERS. Case One: If every boy in a kindergarten class buys a soda and every girl in the same class buys a ...” October 11, 2018 Brent@GMATPrepNow posted a reply to Julie opened a lemonade stand and sold lemonade in two in the Data Sufficiency forum “This question illustrates a common trap on the GMAT. For statement 2, we''re able to write the equation 52x + 58y = 492 , and in high school we learned that, if we''re given 1 equation with 2 variables, we cannot find the value of either variable. However, if we restrict the variables to ...” October 11, 2018 GMATGuruNY posted a reply to Julie opened a lemonade stand and sold lemonade in two in the Data Sufficiency forum “Let X = the number of 52¢ lemonades and Y = the number of 58¢ lemonades. Since the question stem asks for the number of 52¢ lemonades, we get: What is the value of X? Statement 1: X+Y = 9 Since X can be any value between 0 and 9, inclusive, INSUFFICIENT. Statement 2: 52X + 58Y = 492 ...” October 11, 2018 GMATGuruNY posted a reply to For the students in a Physical Fitness Class Section #1, the in the Data Sufficiency forum “Range = highest - lowest. Thus: Lowest = highest - range. In Section 1, lowest = highest - range = X-R. In Section 2, lowest = highest - range = Y-S. If the lowest weight in Section 1 is greater than the lowest weight in Section 2, we get: X-R > Y-S X+S > Y+R. Question ...” October 11, 2018 GMATGuruNY posted a reply to Angela’s grade was in the 90th percentile out of 80 grades in the Problem Solving forum “Percentile means the percentage below: (total below)/(total grades) * 100. Angela''s 80-student class: Since Angela''s grade was in the 90th percentile, 90% of the grades were below Angela''s: (90/100)(80) = 72. 100-student class: Since 19 grades were higher than Angela''s, the remaining ...” October 10, 2018 GMATGuruNY posted a reply to There are 5 cars to be displayed in 5 parking spaces with in the Problem Solving forum “Alternate approach: The 3 red cars must occupy a combination of 3 spaces. From 5 spaces, the number of ways to choose a combination of 3 for the red cars = 5C3 = (5*4*3)/(3*2*1) = 10. Number of options for the blue car = 2. (Either of the 2 remaining spaces.) Number of options for the yellow ...” October 10, 2018 Brent@GMATPrepNow posted a reply to There are 5 cars to be displayed in 5 parking spaces with in the Problem Solving forum “Let R, R, R, B, Y represent the cars (by their colors) Notice that the three R''s are identical. So, the question becomes In how many different ways can we arrange the letters R, R, R, B and Y? ----------------ASIDE------------------------------ When we want to arrange a group of items in ...” October 10, 2018 Brent@GMATPrepNow posted a reply to Is x/11 an integer? in the Data Sufficiency forum “Target question: Is x/11 an integer? Statement 1: 5x/11 is an integer Let''s TEST some values There are several values of x that satisfy statement 1. Here are two: Case a: x = 11. Notice that 5x/11 = 5(11)/11 = 5, which is an integer. In this case, x/11 = 11/11 = 1. So, the answer to the ...” October 10, 2018 Brent@GMATPrepNow posted a reply to Dick and Jane each saved$3000 in 1989. In 1990 Dick save 8 in the Problem Solving forum
“Here''s the original wording: In 1990, Dick saved 8 percent more than in 1989 So, Dick''s savings in 1990 = 1.08($3000) =$3240 In 1990, Dick and Jane saved a total of $5,000. So, Jane''s savings =$5,000 - $3240 =$1760 Approximately what percent less did Jane save in 1990 than in ...”
October 10, 2018
Brent@GMATPrepNow posted a reply to Pam and Sue drove in the same car to a business meeting that in the Problem Solving forum
“Travel time = distance/speed Pam''s travel time = 120 miles/60 mph =2 hours Sue''s travel time = 120 miles/50 mph =2.4 hours Time difference = 2.4 hours - 2 hours = 0.4 hours To convert 0.4 hours to minutes, recognize that 1 hour = 60 minutes So, 0.4 hours = (0.4)(60) minutes = 24 minutes ...”
October 10, 2018
GMATGuruNY posted a reply to Hard Assumption - Manhattan in the Critical Reasoning forum
“Premise: All of the applicants given babies far surpassed the adoption criteria. Conclusion: In placing 8 of the 10 babies with friends, the staff was not guilty of favoritism. Apply the NEGATION TEST. When the correct answer is negated, the conclusion will be invalidated. B, negated: Of ...”
October 10, 2018
Brent@GMATPrepNow posted a reply to A group of medical interns at Bohemus Medical School want to in the Problem Solving forum
“Take the task of arranging dates and break it into stages. Let A, B, C, D and E represent the 5 girls Stage 1: Select a boy to date girl A We can choose any of the 5 boys, so we can complete stage 1 in 5 ways Stage 2: Select a boy to date girl B Since we already selected a boy in ...”
October 9, 2018
GMATGuruNY posted a reply to A group of medical interns at Bohemus Medical School want to in the Problem Solving forum
“In other words: How many ways can 5 girls and 5 guys be divided into pairs, if each pair must consist of one girl and one guy? Number of options for the first girl = 5. (Any of the 5 guys.) Number of options for the second girl = 4. (Any of the 4 remaining guys). Number of options for the ...”
October 9, 2018
Brent@GMATPrepNow posted a reply to A school library contains 200 hardcover and 300 paperback in the Problem Solving forum
“Another approach is to use the Double Matrix Method. This technique can be used for most questions featuring a population in which each member has two characteristics associated with it (aka overlapping sets questions). Here, we have a population of books, and the two characteristics are: - ...”
October 9, 2018
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“Here''s our video on the Double Matrix Method for overlapping sets: https://www.youtube.com/watch?v=jK-tiBrrf04 Cheers, Brent”
October 9, 2018
GMATGuruNY posted a reply to If x, y, and z are positive numbers, Is z between x and y? in the Data Sufficiency forum
“Statement 1: x < 2z < y Let x=2 and y=10. In this case: 2 < 2z < 10 1 < z < 5. If z=4, then it is between x=2 and y=10. If z=1.5, then it is not between x=2 and y=10. INSUFFICIENT. Statement 2: 2x < z < 2y Let x=2 and y=10. In this case: 2*2 < z ...”
October 9, 2018
Brent@GMATPrepNow posted a reply to If x, y, and z are positive numbers, Is z between x and y? in the Data Sufficiency forum
“Target question: Is z between x and y? Statement 1: x < 2z < y There are several sets of values of x, y and z that satisfy this condition. Here are two: Case a: x = 3, y = 10, and z = 2, in which case z is NOT between x and y Case b: x = 1, y = 10, and z = 3, in which case z IS ...”
October 9, 2018
Brent@GMATPrepNow posted a reply to If the product of X and Y is a positive number, is the sum in the Data Sufficiency forum
“IMPORTANT CONCEPTS: An ODD power preserves the sign of the base. For example, (-5)^3 = -125 and 2^5 = 32 An EVEN power always yields a positive number (as long as the base ≠ 0 For example, (-5)^4 = 625 and 2^6 = 64 Target question: Is the sum of x and y negative? Given: the ...”
October 9, 2018
Brent@GMATPrepNow posted a reply to DS: Difficulty level: 700, Source: Economist in the GMAT Math forum
“The key word here is must So, if we can find a case in which an answer choice is NOT true, then we can eliminate that answer choice. A. x is odd and y is even. x = 3 and y = 11 satisfies the condition that x/y is not an integer Since y is NOT even, we can ELIMINATE A B. x is odd and y is ...”
October 9, 2018
Brent@GMATPrepNow posted a reply to James invested $5000 in scheme A for 1 year at a simple in the Problem Solving forum “Scheme A Interest = 5% of$5,000 = $250 Scheme B 10% interest compounded semi-annually means that the interest is compounded 2 times (in 1 year) at a rate of 5% each time One option is to apply the compound interest formula, but since we''re only compounding the interest twice, it may be ...” October 9, 2018 GMATGuruNY posted a reply to If s is an integer between 0 and 10, is t less than the av in the Data Sufficiency forum “The average of s and 10 lies HALFWAY between s and 10 on the number line: s------------AVERAGE------------10 Statement 1: Since t closer to 10 than to s, t must be greater than the average of s and 10, as shown here: s-----------AVERAGE---t----------10 Thus, the answer to the question stem is ...” October 9, 2018 GMATGuruNY posted a reply to A group of 10 people consists of 3 married couples and 4 si in the Problem Solving forum “Good committees = total committees - bad committees. Total committees: From 10 people, the number of ways to choose 4 = 10C4 = (10*9*8*7)/(4*3*2*1) = 210. Bad committees: Since a good committee includes at most 1 married couple, a bad committee is composed of 2 married couples. From 3 ...” October 9, 2018 Brent@GMATPrepNow posted a reply to A retailer buys cases of 24 shirts for$30/case and then in the Problem Solving forum
“The key information here is that the retailer sold all the shirts it purchased This is a huge hint! For example, we know that the retailer did NOT buy only 1 case of 24 shirts, because 24 shirts will not divide into packs of 5 shirts. Likewise, we know that the retailer did NOT buy 2 cases of ...”
October 8, 2018
Brent@GMATPrepNow posted a reply to If x^2-3x=10, what is the value of x? in the Data Sufficiency forum
“ Given: x² - 3x = 10 Subtract 10 from both sides to get: x² - 3x - 10 = 0 Factor: (x - 5)(x + 2) = 0 So, EITHER x = 5 OR x = -2 Target question: What is the value of x? Statement 1: x² - 4 = 0 Factor: (x + 2)(x - 2) = 0 So, EITHER x = -2 OR x = 2 When we combine this with the fact ...”
October 8, 2018
Brent@GMATPrepNow posted a reply to What is the greatest prime factor of 1+2+3+….+36? in the Problem Solving forum
“Useful formula: 1 + 2 + 3 + 4 + . . . . + n = (n)(n + 1)/2 So, 1 + 2 + 3 + …. + 36 = (36)(36 + 1)/2 = (36)(37)/2 = (18)(37) = (2)(3)(3)(17) So, the greatest prime factor is 37 Answer: E Cheers, Brent”
October 8, 2018
Brent@GMATPrepNow posted a reply to Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“In this short (3:25) video, we''ll examine the age-old question When do I use IF and when do we use WHETHER? Video link: https://www.youtube.com/watch?v=F2ZHtB088us Cheers, Brent”
October 7, 2018
Brent@GMATPrepNow posted a reply to All assets in Karina's investment portfolio are divided in the Problem Solving forum
“Let''s say Karina''s entire portfolio is worth $100 altogether. So, we want to divide this$100 into four integer amounts: w, x, y, z, where w < x < y < z, and we want to minimize the value of z In order to MINIMIZE the value of the z, we must MAXIMIZE the values of w, x, and y. Now ...”
October 7, 2018
Brent@GMATPrepNow posted a reply to Beth and Jim each received a salary increase. If Jim's in the Data Sufficiency forum
“Target question: Did Beth receive a greater dollar increase in salary than Jim? Given: Jim''s salary was increased by the same percent as Beth''s salary Statement 1: Before the increases, Jim''s salary was greater than $25,000. Since we have no information about Beth, there''s no way to ...” October 7, 2018 Brent@GMATPrepNow posted a reply to Problem solving: Difficulty level: 700, Source: Jamboree in the Problem Solving forum “Take: x² + 5|x| + 6 = 0 Subtract 6 from both sides to get: x² + 5|x| = -6 KEY CONCEPT: x² ≥ 0 and |x| ≥ 0 for all values of x In other words, x² will always be greater than or equal to 0 And |x| will always be greater than or equal to 0, which means 5|x| will always be greater than or ...” October 7, 2018 GMATGuruNY posted a reply to Problem solving: Difficulty level: 700, Source: Princeton in the Problem Solving forum “For any evenly spaced set: sum = (number)(median) We can PLUG IN THE ANSWERS, which represent the sum. Since the number of integers can be 5 or 7, the sum must be a multiple of both 5 and 7. Eliminate A, which is not divisible by 5. Eliminate D, which is not divisible by 7. The equation in ...” October 7, 2018 Brent@GMATPrepNow posted a reply to TRICKY! There are n teams playing in a basketball tournam in the Problem Solving forum “Good catch regor60! A few people alerted me to this error earlier in the day, but I was on the road and couldn''t respond. Man, I must have solved the question 3 or 4 times to make sure the numbers added up, BUT I never considered the impossibility of more than one team winning every game. ...” October 7, 2018 GMATGuruNY posted a reply to Health insurance Plan A requires the insured to pay$1000 or in the Problem Solving forum
“THE INSURED is the person covered by the insurance. Plan A: If $1000 is LESS than 50% of the cost level, then THE INSURED pays$1000, and PLAN A pays the remainder. If $1000 is MORE than 50% of the cost level, then THE INSURED pays 50% of the cost level, and PLAN A pays the remainder. Plan ...” October 6, 2018 Brent@GMATPrepNow posted a reply to Is -3*x^3 <= -3? in the Data Sufficiency forum “Target question: Is (-3)(x³) ≤ -3? This is a good candidate for rephrasing the target question. Take: (-3)(x³) ≤ -3? Divide both sides by -3 to get: x³ ≥ 1 Under what circumstance will x³ be greater than or equal to 1? Well, x³ EQUALS 1 when x = 1 So, x³ will be greater than ...” October 6, 2018 Brent@GMATPrepNow posted a reply to If x + 5 > 2 and x - 3 < 7, the value of x must be bet in the Problem Solving forum “GIVEN: x + 5 > 2 Subtract 5 from both sides of the inequality to get: x > -3 Or we can write this as -3 < x GIVEN: x - 3 < 7 Add 3 to both sides of the inequality to get: x < 10 COMBINE the inequalities to get: -3 < x < 10 Answer: A Cheers, Brent” October 6, 2018 GMATGuruNY posted a reply to John tossed a fair coin 3 times. What is the probability in the Problem Solving forum “P(TTH) = 1/2 * 1/2 * 1/2 = 1/8. Since H can occur on the 1st, 2nd or 3rd flip, we multiply by 3: 3*(1/8) = 3/8. The correct answer is C.” October 6, 2018 GMATGuruNY posted a reply to Mixture Problem DS in the Data Sufficiency forum “Yes -- each statement conveys the same information, since doubling the total volume is the equivalent of reducing the acid concentration by 1/2.” October 6, 2018 GMATGuruNY posted a reply to The value of a share was 25% less in the 2nd quarter over in the Problem Solving forum “Let the 1st-quarter value = 100. Since 2nd-quarter value is 25% less, the 2nd-quarter value = 100 - (25% of 100) = 100 - 25 = 75. Since the 3rd-quarter value is 20% more than the 2nd-quarter value, the 3rd-quarter value = 75 + (20% of 75) = 75 + 15 = 90. Since the 4th-quarter value must equal 120 ...” October 6, 2018 GMATGuruNY posted a reply to Mixture Problem DS in the Data Sufficiency forum “Statement 1 indicates that 80 grams of water are added to the 80 grams of original solution, DOUBLING the total volume from 80 grams to 160 grams Statement 2 indicates that the added water reduces the acid concentration by 1/2. Doubling the total volume will reduce the acid concentration by 1/2 ...” October 6, 2018 GMATGuruNY posted a reply to Each year for 4 years, a farmer increased the number of in the Problem Solving forum “We can PLUG IN THE ANSWERS, which represent the original number of trees. Since the number of trees increases by 1/4 each year, the correct answer must be a multiple of 4. The last 2 digits of a multiple of 4 must themselves form a multiple of 4. Eliminate A (1250) and C (2250), since 50 is ...” October 5, 2018 Brent@GMATPrepNow posted a reply to Each year for 4 years, a farmer increased the number of in the Problem Solving forum “Here''s another approach: First notice that, if the number of trees increases by 1/4, then the new number is 5/4 times the original number. Let x = the # of trees in the orchard at the beginning of the 4 year period. (5/4)x = # of trees after 1 year (5/4)(5/4)x = # of trees after 2 years ...” October 5, 2018 Brent@GMATPrepNow posted a reply to Health insurance Plan A requires the insured to pay$1000 or in the Problem Solving forum
“Here''s an algebraic approach: Let T = TOTAL COST Plan A: Person pays EITHER $1000 OR 0.5T, whichever is LESS Plan B: Person pays$300 plus 20% of anything over $300. In other words, the person pays$300 + 0.2(T - 300) Since Plan A has two different scenarios, we need to test both. That ...”
October 5, 2018
Brent@GMATPrepNow posted a new topic called Bite-sized video lessons from GMAT Prep Now in the GMAT Math forum
“I thought I''d start a thread featuring some of the videos from our course. This first video is one of my favorites. It covers a useful mental-math technique called Multiplying by Doubling and Halving (length 3:25) Video link: https://www.youtube.com/watch?v=D__dWwmgq2w All the best on ...”
October 5, 2018
Brent@GMATPrepNow posted a new topic called TRICKY! There are n teams playing in a basketball tournam in the Problem Solving forum
“Several teams are competing in a basketball tournament, and each team plays every other team once. Each game has exactly 1 winner and 1 loser (no ties). If 4 teams lost exactly 5 games, 5 teams won exactly 3 games, and each of the remaining teams won all of its games, what is the total number of ...”
October 5, 2018
Brent@GMATPrepNow posted a reply to Andrew bought pizzas for his swim team. Pepperoni pizzas in the Problem Solving forum
“This question illustrates the difference between the abstract math and real world math. From the given information, we''re able to create ONE equation: 13p + 17c = 184 In high school, we learned that, if we''re given 1 equation with 2 variables, we cannot find the value of either variable, so ...”
October 5, 2018
Brent@GMATPrepNow posted a reply to ||2-3|-|2-5||=? in the Problem Solving forum
“||2-3|-|2-5|| = ||-1|-|-3|| = |1-3|| = |-2| = 2 Answer: B Cheers, Brent”
October 5, 2018
Brent@GMATPrepNow posted a reply to What is the perimeter of quadrilateral Q? in the Data Sufficiency forum
“Target question: What is the perimeter of quadrilateral Q? If we recognize that each statement alone is not sufficient, we can jump straight to...... Statements 1 and 2 combined There are several quadrilaterals that satisfy BOTH statements. Here are two: Case a: rectangle Q has ...”
October 5, 2018
GMATGuruNY posted a reply to A chessboard is an 8×8 array of identically sized squares. in the Problem Solving forum
“Case 1: Every 6-block rectangle with a base of 2 and a height of 3 yields 4 possible L-shapes: https://i.postimg.cc/1gJCfb5J/chessboard_L_shape_1.png Chessboard: https://i.postimg.cc/LYJThXW8/chessboard_whole.png The base for the 6-block rectangle shown above can appear in rows 1 through 6, ...”
October 5, 2018
GMATGuruNY posted a reply to Amit and Ian paint a wall in alternating shifts. First Amit in the Problem Solving forum
“During each of Amit''s 4 shifts, he paints 1/2 of the room, leaving 1/2 the room unpainted. Since 1/2 of the room is left unpainted FOUR TIMES, the total fraction left unpainted as a result of Amit''s 4 shifts = (1/2)⁴. Since Ian works after each of Amit''s first 3 shifts, Ian paints a total ...”
October 5, 2018
Brent@GMATPrepNow posted a reply to A car salesman earns a base salary of $1,000 per month plus in the Problem Solving forum “Let x = number of cars sold in 1 month So, his pay =$1000 + ($200)(n) If he earned$2,200 in February, how many cars does he have to sell in March in order to double his February earnings? If we double $2,200, we get$4,400 We need: $1,000 + ($200)(n) = $4400 Subtract$1,000 from both sides ...”
October 4, 2018
Brent@GMATPrepNow posted a reply to If p and q are prime numbers, is pq+1 an odd number? in the Data Sufficiency forum
“Be careful, deloitte247 You haven''t used the information about p and q being prime numbers. Cheers, Brent”
October 4, 2018
Brent@GMATPrepNow posted a reply to In the figure above, A is the center of the circle, DF is 5, in the Problem Solving forum
“As you can see from my solution above, this question is a time-killer (even if you answer it correctly!!) So, if you''re running short on time, you can reduce the correct answers to two options, and make your best guess How so? IMPORTANT: the diagrams in GMAT problem solving questions are DRAWN ...”
October 4, 2018
Brent@GMATPrepNow posted a reply to In the figure above, A is the center of the circle, DF is 5, in the Problem Solving forum
“As you can see from my solution above, this question is a time-killer (even if you answer it correctly) So, if you''re running short on time, you can reduce the correct answers to two options, and make your best guess How so? IMPORTANT: the diagrams in GMAT problem solving questions are DRAWN TO ...”
October 4, 2018
Brent@GMATPrepNow posted a reply to In the figure above, A is the center of the circle, DF is 5, in the Problem Solving forum
“Let x = the length of AF https://i.imgur.com/pT36mTR.png This means AD = x + 5 = radius of the circle. This is convenient, because AE is also a radius of the circle. So, AE must have length x + 5 https://i.imgur.com/aLGqKow.png At this point, we can focus on the RIGHT TRIANGLE below: ...”
October 4, 2018
Brent@GMATPrepNow posted a reply to If p and q are prime numbers, is pq+1 an odd number? in the Data Sufficiency forum
“ Given: p and q are prime numbers Target question: Is pq + 1 an odd number? This is a good candidate for rephrasing the target question. In order for pq + 1 to be odd, we need pq to be EVEN So, we COULD rephrase our target question as Is pq an even number?, but we can do even better than ...”
October 4, 2018
Brent@GMATPrepNow posted a reply to A political candidate collected $1,749 from a fund raising in the Problem Solving forum “In order to MAXIMIZE the number of contributors, we must MINIMIZE the amount that each supporter contributes. So, let''s say that each supporter contributes exactly$50 (which is the minimum about that each supporter contributes) $50 divides into$1,749 a total of 34 times (with $49 left over). ...” October 4, 2018 Brent@GMATPrepNow posted a reply to If x^2 + 3x + 3 = 5x + 6 then x equals in the Problem Solving forum “nonplus2''s approach is the as mine, but a reasonably fast alternative approach is to test the answer choices . Answer choice A suggests that one possible solution is x = -1 So, plug x = -1 into the equation to get: (-1)² + 3(-1) + 3 = 5(-1) + 6 Simplify to get: 1 = 1. Perfect!!! So, x = -1 ...” October 4, 2018 Brent@GMATPrepNow posted a reply to A thin piece of wire 40 meters long is cut into two pieces. in the Problem Solving forum “One approach is to plug in a value for r and see what the output should be. Let''s say r = 0. That is, the radius of the circle = 0 This means, we use the entire 40-meter length of wire to create the square. So, the 4 sides of this square will have length 10, which means the area = 100 So, ...” October 4, 2018 GMATGuruNY posted a reply to A thin piece of wire 40 meters long is cut into two pieces. in the Problem Solving forum “Since the answer choices are in terms of a variable -- the value of r -- we can PLUG IN. Let the ENTIRE WIRE be used to form the square. Then: Perimeter of the square = 40. Side = 10. Area = 100. Circle area + square area = 0 + 100 = 100. This is our target. Since the circle has no ...” October 4, 2018 Brent@GMATPrepNow posted a reply to The price of a phone call consists of a standard connection in the Problem Solving forum “A 10-minute call costs$2.90 and a 16-minute call costs $4.40$4.40 - $2.90 =$1.50, and 16 minutes - 10 minutes = 6 minutes So, the extra $1.50 paid for extra 6 minutes of calling So,$0.75 would pay for 3 minutes of calling How much does a 13-minute call cost? A 10-minute call costs ...”
October 4, 2018
GMATGuruNY posted a reply to If x and y are positive integers, is x^2*y^2 even ? in the Data Sufficiency forum
“x²y² will be even unless both x and y are ODD. Question stem, rephrased: Are x and y both odd? Statement 1: x+5 is prime number greater than 2 and thus must be ODD. Implication: x+5 = ODD x = ODD - 5 = ODD - ODD = EVEN. Since x is even, x and y cannot both be odd. SUFFICIENT. ...”
October 4, 2018
GMATGuruNY posted a reply to A hiker walking at a constant rate of 4 miles per hour is in the Problem Solving forum
“Rate and time have a RECIPROCAL RELATIONSHIP. The RATE RATIO for the hiker and cyclist = 4 mph : 20 mph = 1:5. Thus: The TIME RATIO for the hiker and cyclist = the reciprocal of the rate ratio = 5:1. Implication: The hiker will take 5 TIMES AS LONG as the cyclist to travel the same ...”
October 4, 2018
GMATGuruNY posted a reply to How many ounces of water must be added to 10 ounces of 3 % in the Problem Solving forum
“Alcohol percentage in the original solution: 3%. Alcohol percentage in the added water: 0%. Alcohol percentage in the mixture: 1%. Let S = the original solution and W = the added water. The following approach is called ALLIGATION -- a very efficient way to handle MIXTURE PROBLEMS. Step 1: ...”
October 3, 2018
GMATGuruNY posted a reply to Vivian drives to her sister's house and back. She takes the in the Problem Solving forum
“When the same distance is traveled at two different speeds, the average speed for the entire trip will be a bit LESS than the average of the two speeds. Since (70+50)/2 = 60, the average speed for Vivian''s''s entire trip must be a bit less than 60. The correct answer is B.”
October 3, 2018
GMATGuruNY posted a reply to Tom’s Mom is five times as old as him. In 6 years, Tom’ in the Problem Solving forum
“An alternate approach is to PLUG IN THE ANSWERS, which represents Tom''s current age. When the correct answer is plugged in, Mom''s age in 6 years will be 3 times Tom''s age in 6 years. D: Tom = 6 Since Mom is currently 5 times as old as Tom, Mom = 5*6 = 30. Tom''s age in 6 years = 6+6 = 12. ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to How many ounces of water must be added to 10 ounces of 3 % in the Problem Solving forum
“The original solution contains 10 ounces 3% of that is alcohol 3% of 10 = 0.3 So, the original solution contains 0.3 ounces of alcohol Let x = the amount of water (in ounces) that must be added So, the volume of the RESULTING solution = 10 + x ounces IMPORTANT: Since we''re adding water ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to Ken has a group of coins worth $6.70. He has four times as m in the Problem Solving forum “Let x = the NUMBER of dimes So, 4x = the NUMBER of nickels And 4x - 20 = the NUMBER of quarters One dime is worth$0.1, so 0.10x = the total VALUE of the dimes (in dollars) Likewise, (0.05)(4x) = the total VALUE of the nickels (in dollars) And (0.25)(4x - 20) = the total VALUE of the ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to Goku and Vegeta are waiting in a line, are there more than 1 in the Data Sufficiency forum
“Target question: Are there more than 10 people waiting in the line? Head straight to... Statements 1 and 2 combined There are several scenarios that satisfy BOTH statements. Here are two: Case a: BACK A, B, C, D, Vegeta, Picollo, Goku, E, F, G, H FRONT. In this case, the answer to the ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to Vivian drives to her sister's house and back. She takes the in the Problem Solving forum
“One approach is to assign a "nice" value (one that works well with 50 mph and 70 mph) to the distance her sister''s house. So, let''s say the distance is 350 miles Average speed = (total distance traveled)/(total travel time) TOTAL distance = 350 miles + 350 miles = 700 miles ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to Tom’s Mom is five times as old as him. In 6 years, Tom’ in the Problem Solving forum
“Tom’s Mom is five times as old as him. Let T = Tom''s PRESENT age So, 5T = Mom''s PRESENT age This also means: Let T + 6= Tom''s age IN 6 YEARS and 5T + 6 = Mom''s age IN 6 YEARS In 6 years, Tom’s Mom will be three times as old as Tom. In other words: (Mom''s age IN 6 YEARS) = ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to A “descending number” is a three-digit number, such that in the Problem Solving forum
“Let''s use some counting methods to solve this. P(selected number is "descending") = total # of descending numbers/total # of 3-digit numbers total # of 3-digit numbers 3-digit numbers go from 100 to 999 inclusive A nice rule says: the number of integers from x to y inclusive ...”
October 3, 2018
Brent@GMATPrepNow posted a reply to Challenge question: If y < 0 < x, is x/y > -1? in the Data Sufficiency forum
“I checked the link you provided, Fabio. For me, the response from the test-makers that sticks out the most is this: "it is highly unlikely that you would come across a question with independently sufficient statements that contradict each other" I think the person answering the ...”
October 2, 2018
Brent@GMATPrepNow posted a reply to Challenge question: If y < 0 < x, is x/y > -1? in the Data Sufficiency forum
“My apologies. I posted my question without noticing its FATAL FLAW. KEY CONCEPT: On the GMAT, the two statements in a Data Sufficiency question will never contradict each other (for more on this, see the video below) Let''s examine the main issue. Statement 1: x + y > 0 Okay, so x + ...”
October 2, 2018
GMATGuruNY posted a reply to If 3 different numbers are selected from the first 8 prime n in the Problem Solving forum
“First 8 prime numbers: 2, 3, 5, 7, 11, 13, 17, 19. The sum will be even if 2 is among the three numbers selected, with the result that the sum = EVEN PRIME + ODD PRIME + ODD PRIME = EVEN. Since 3 NUMBERS are selected from 8 OPTIONS, the probability that 2 will be among the three numbers selected = ...”
October 2, 2018
Brent@GMATPrepNow posted a reply to During a two-week period, the price of an ounce of silver in the Problem Solving forum
“Another approach is to test a "nice" value x A great value would be $80 (since we get$100 after we increase $80 by 25%) So, x =$80 In other words, the price of silver was $80 per ounce at the beginning of the two-week period. During a two-week period, the price of an ounce of ...” October 2, 2018 Brent@GMATPrepNow posted a new topic called Challenge question: If y < 0 < x, is x/y > -1? in the Data Sufficiency forum “If y < 0 < x, is x/y > -1? (1) x + y > 0 (2) 3x < -2y Answer: D Difficulty level: 600 - 650 Source: www.gmatprepnow.com” October 2, 2018 Brent@GMATPrepNow posted a reply to For all values of x and y , let x&y be defined by x& in the Problem Solving forum “Nice question! GIVEN: x&y = xy − x + 1 So, take the equation: (a − 2)&a = a&(a + 1) Apply rules to get the equation: (a - 2)(a) - (a - 2) + 1 = (a)(a + 1) - a + 1 Expand: a² - 2a - a + 2 + 1 = a² + a - a + 1 Simplify: a² - 3a + 3 = a² + 1 Subtract a² from both sides ...” October 2, 2018 Brent@GMATPrepNow posted a reply to If 3 different numbers are selected from the first 8 prime n in the Problem Solving forum “The first 8 prime numbers are: {2, 3, 5, 7, 11, 13, 17, 19} Notice that only one prime number is EVEN, and the remaining seven numbers are ODD. Also notice that the sum of 3 numbers will be EVEN only if one of the three selected numbers is 2 So, the question is really asking "What is the ...” October 2, 2018 Brent@GMATPrepNow posted a reply to The symbol Ω represents one of the following operations: ad in the Data Sufficiency forum “Target question: What is the value of 1 Ω 1? Given: Ω represents one of the following operations: addition, subtraction, multiplication or division. Statement 1: 2 Ω 2 = 4 2 - 2 = 0, so Ω CANNOT represent subtraction. 2 ÷ 2 = 1, so Ω CANNOT represent division. 2 + 2 = 4, so ...” October 2, 2018 Brent@GMATPrepNow posted a reply to On a 20 mile course, Pat bicycled at an average rate of 30 in the Problem Solving forum “Let''s start with a WORD EQUATION (Distance traveled at 30 mph) + (Distance traveled at 8 mph) = 20 miles Distance = (rate)(time) Let t = the time (in hours) Pat spent running at 8 mph Aside: 12 minutes = 1/5 hours So, we get: (30 miles per hour)(1/5 hours) + (8 miles per hour)(t ...” October 2, 2018 GMATGuruNY posted a reply to In a certain office, 50 percent of the employees are college in the Data Sufficiency forum “Let T = the total number of employees. Since 60% of the employees are over 40, we get: Over 40 = 0.6T 30% of those over 40 -- in other words, 30% of the expression in blue -- have master''s degrees. Thus: Over 40 with master''s = 0.3(0.6T). To calculate the value of the expression in ...” October 2, 2018 GMATGuruNY posted a reply to On a 20 mile course, Pat bicycled at an average rate of 30 in the Problem Solving forum “Since Pat travels at 30 miles per hour for the first 12 minutes -- the equivalent of 1/5 hour -- the distance traveled in the first 12 minutes = (30)(1/5) = 6 miles. Since the remaining 14 miles are traveled at 8 miles per hour, the time to travel the remaining 14 miles = 14/8 = 7/4 hours = 1 hour ...” October 2, 2018 GMATGuruNY posted a reply to 190 students go to a school bake sale. 95 buy a chocolate in the Problem Solving forum “Total = Group 1 + Group 2 - Both + Neither Here: Total = 190. Group 1 = 95 who buy chocolate chip. Group 2 = 75 who buy peanut butter. Plugging these values into the equation above, we get: 190 = 95 + 75 - Both + Neither 20 + Both = Neither Neither = 20 + Both. To minimize the value of ...” October 2, 2018 GMATGuruNY posted a reply to Is x^3-x>0？ in the Data Sufficiency forum “Question stem, rephrased: Is x³ > x? Statement 1: x > 1 When a positive value greater than 1 is cubed, the result is greater than the original number: x=2 --> 2³ > 2 x=3 --> 3³ > 3 x=4 --> 4³ > 4 In every case, x³ > x. Thus, the answer to the rephrased ...” October 2, 2018 GMATGuruNY posted a reply to The greatest common factor of 16 and the positive integer n in the Problem Solving forum “The greatest common factor of 16 and the positive integer n is 4, and the greatest common factor of n and 45 is 3. Draw a VENN DIGRAM showing where the prime factors of n, 16 and 45 overlap: https://i.postimg.cc/xkyNCFg7/GCF_Venn_n_16_and_45.jpg The diagram implies the following: Since n and ...” October 2, 2018 Brent@GMATPrepNow posted a reply to The greatest common factor of 16 and the positive integer n in the Problem Solving forum “Now, we can use ELIMINATION to find the correct answer. Goal: Find GCF of 210 and n. 210 = (2)(3)(5)(7) The greatest common factor of 16 and the positive integer n is 4 16 = (2)(2)(2)(2) 4 = (2)(2) So, we know for certain that the PRIME FACTORIZATION of n has TWO 2''s (and no more than ...” October 2, 2018 Brent@GMATPrepNow posted a reply to Jan lives x floors above the ground floor of a highrise in the Problem Solving forum “Let''s first convert 7 minutes to SECONDS in order to have uniform units of measurement. 7 minutes = 420 seconds Let''s start with a word equation Jan''s travel time (in seconds) WALKING down = Jan''s travel time (in seconds) via ELEVATOR + 420 seconds It takes her 30 seconds per floor to ...” October 1, 2018 Brent@GMATPrepNow posted a reply to Five letters A, P, P, L and E are listed in a row. How many in the Problem Solving forum “Here''s an approach that doesn''t require us to subtract the bad arrangements. Take the task of arranging the 5 letters and break it into stages. Stage 1: Arrange the letters A, L, E in a row We can arrange n unique objects in n! ways. So, we can arrange the 3 letters in 3! ways (= 6 ...” October 1, 2018 Brent@GMATPrepNow posted a reply to Jevan must paint 3 rooms in a house. Room A can be painted in the Problem Solving forum “Take the task of painting the 3 rooms and break it into stages. Stage 1: Select a color for Room A Room A can be painted orange, red or green So, we can complete stage 1 in 3 ways Stage 2: Select a color for Room B Room B can be painted orange, white or red. So we can complete this ...” October 1, 2018 Brent@GMATPrepNow posted a reply to Improve My Overall Score in the Last Leg of Preparation? in the GMAT Strategy forum “The resource labeled "OG2018" has questions from the 2018 OG See: https://www.beatthegmat.com/mba/official-guide-2018-library Cheers, Brent” October 1, 2018 Brent@GMATPrepNow posted a reply to Improve My Overall Score in the Last Leg of Preparation? in the GMAT Strategy forum “Look no further<i class="em em-grinning"></i> : https://www.beatthegmat.com/official-guide-question-library-t296755.html Cheers, Brent” October 1, 2018 Brent@GMATPrepNow posted a reply to If m and n are integers, is mn an odd integer? in the Data Sufficiency forum “Some important rules: #1. ODD +/- ODD = EVEN #2. ODD +/- EVEN = ODD #3. EVEN +/- EVEN = EVEN #4. (ODD)(ODD) = ODD #5. (ODD)(EVEN) = EVEN #6. (EVEN)(EVEN) = EVEN Target question: Is mn an odd integer? Given: m and n are integers Statement 1: m(n+1) is even Let''s test some ...” October 1, 2018 GMATGuruNY posted a reply to Five letters A, P, P, L and E are listed in a row. How many in the Problem Solving forum “Good arrangements = total arrangements - bad arrangements. Total arrangements: Number of ways to arrange 5 elements = 5!. But when an arrangement includes IDENTICAL elements, we must divide by the number of ways each set of identical elements can be ARRANGED. The reason: When the ...” October 1, 2018 Brent@GMATPrepNow posted a reply to If n is an integer, is n even? in the Data Sufficiency forum “Some important rules: 1. ODD +/- ODD = EVEN 2. EVEN +/- ODD = ODD 3. EVEN +/- EVEN = EVEN 4. (ODD)(ODD) = ODD 5. (ODD)(EVEN) = EVEN 6. (EVEN)(EVEN) = EVEN Target question: Is integer n EVEN? Statement 1: n² - 1 is an odd integer n² - 1 = (n + 1)(n - 1) So, statement 1 is ...” October 1, 2018 Brent@GMATPrepNow posted a reply to When positive integer n is divided by 13, the remainder is 2 in the Problem Solving forum “When it comes to remainders, we have a nice rule that says: If N divided by D leaves remainder R, then the possible values of N are R, R+D, R+2D, R+3D,. . . etc. For example, if k divided by 5 leaves a remainder of 1, then the possible values of k are: 1, 1+5, 1+(2)(5), 1+(3)(5), ...” September 30, 2018 Brent@GMATPrepNow posted a reply to A marketing firm determined that, of 200 households surveyed in the Problem Solving forum “We can also solve this question using the Double Matrix Method. Here, we have a population of 200 households , and the two characteristics are: - using or not using Brand A soap - using or not using Brand B soap So, we can set up our matrix as follows (where "~" represents ...” September 30, 2018 Brent@GMATPrepNow posted a reply to Lindsay can paint 1/x of a certain room in 20 minutes. What in the Problem Solving forum “Given: Lindsay can paint 1/x of a certain room in 20 minutes So, in 1 HOUR, Lindsay can paint 3/x of the room Given: Lindsay and Joseph can paint the room in 1 HOUR. During that one hour, Lindsay can paint 3/x of the room. So, during that 1 HOUR, Joseph must paint the rest (whatever Lindsay ...” September 30, 2018 Brent@GMATPrepNow posted a reply to PS : In a certain clothing store in the Problem Solving forum “Let C = price of one pair of the CHEAPEST socks So, 2C - 1 = price of one pair of the MOST EXPENSIVE socks A customer notices that for exactly$18, she can buy three fewer pairs of the most expensive socks than the cheapest socks. As a word equation, we can write: (# of pairs of EXPENSIVE ...”
September 30, 2018
Brent@GMATPrepNow posted a reply to If x and y are positive integers, is x/y < (x+5)/(y+5)? in the Data Sufficiency forum
“ Given: x and y are positive integers Target question: Is x/y < (x+5)/(y+5)? This is a good candidate for rephrasing the target question. Since y is POSITIVE, we can safely take the inequality x/y < (x+5)/(y+5) and multiply both sides by y. When we do this, we get: x < ...”
September 30, 2018
Brent@GMATPrepNow posted a reply to If x is the greatest common factor of 36 and 96, what is the in the Problem Solving forum
“Mitch''s solution is the approach I''d take, but another way to answer this question is to simply LIST the factors of each value and then find the GREATEST factor they have in common. When listing factors, it''s best to do so in pairs of values with a given product (either 36 or 96). Here''s what ...”
September 30, 2018
Brent@GMATPrepNow posted a reply to If a photocopier makes 2 copies in 1313 second, then, at the in the Problem Solving forum
“We can also solve this question with equivalent ratios We''ll first convert 4 minutes to SECONDS in order to use the same units of measurement throughout the solution. 1 minute = 60 seconds So, 4 minutes = 240 seconds. Now let''s set up and equation using the ratio # of copies/time in ...”
September 30, 2018
GMATGuruNY posted a reply to If a, b, c, d, e are consecutive positive integers such that in the Problem Solving forum
“For any set of consecutive integers, average = median. Let the five integers = 1, 2, 3, 4, 5. Average of 2, 3, 4 and 5 = 3.5. Average of 1, 2, 3, and 4 = 2.5. Difference between the averages = 3.5 - 2.5 = 1. The correct answer is D.”
September 30, 2018
GMATGuruNY posted a reply to If a, b, c, d, e are integers such that a<b<c<d< in the Data Sufficiency forum
“Statement 1: For any set of consecutive integers, average = median. Case 1: 1, 2, 3, 4, 5 Average of 2, 3, 4 and 5 = 3.5. Average of 1, 2, 3, and 4 = 2.5. Difference between the averages = 3.5 - 2.5 = 1. Case 2: 2, 3, 4, 5, 6 Average of 3, 4, 5, and 6 = 4.5. Average of 2, 3, 4 and 5 = ...”
September 30, 2018
GMATGuruNY posted a reply to If x is the greatest common factor of 36 and 96, what is the in the Problem Solving forum
“36 = 2*2*3*3 96 = 2*2*2*2*2*3 GCF = the product of the factors in blue = 2*2*3 = 12. Sum of the digits = 1+2 = 3. The correct answer is B.”
September 30, 2018
GMATGuruNY posted a reply to Bob invested $2000 in fund A and$1000 in fund B. Over the in the Problem Solving forum
“Fund A after 2 years: 2000 + (10% of 2000) + (2)(1% of 2000) = 2000 + 200 + 2(20) = 2240. Fund B after 1 year: 1000 + (30% of 1000) = 1000 + 300 = 1300. Fund B after 2 years: 1300 + (30% of 1300) = 1300 + 390 = 1690. Difference after two years: 2240 - 1690 = 550. The correct answer is ...”
September 30, 2018
GMATGuruNY posted a reply to If a photocopier makes 2 copies in 1313 second, then, at the in the Problem Solving forum
“Using ratios, convert 4 minutes into copies: (4 minutes) * (60 seconds)/(1 minute) * (2 copies)/(1/3 second) = 1440 copies. The correct answer is E.”
September 30, 2018
GMATGuruNY posted a reply to Lindsay can paint 1/x of a certain room in 20 minutes. What in the Problem Solving forum
“Let the room = 20 units. Let x = 4. Since Lindsay paints 1/x of the room in 20 minutes -- the equivalent of 1/3 hour -- Lindsay''s rate = (1/4) * 20 = 5 units per 1/3 hour = 15 units per hour. Since Lindsay and Joseph paint the entire room in 1 hour, their combined rate = 20 units per hour. ...”
September 29, 2018
Brent@GMATPrepNow posted a reply to A number of people each wrote down one of the first 30 posit in the Data Sufficiency forum
“Target question: Were any of the integers written down by more than one of the people? Given: A number of people each wrote down one of the first 30 positive integers. Statement 1: The number of people who wrote down an integer was greater than 40. If there were exactly 30 people, ...”
September 29, 2018
Brent@GMATPrepNow posted a reply to A computer programmer needs to print 148 documents. The in the Problem Solving forum
“We can also answer this question using a step-by-step approach based on number sense. IMPORTANT: The word approximately typically suggests that we can be somewhat aggressive with our estimation There are 148 documents and the documents have an average length of 10 pages So, the TOTAL number ...”
September 29, 2018
GMATGuruNY posted a reply to 50% of students' study science and 30% of science students in the Problem Solving forum
“Let the total number of students = 100. Since 50% of the students study science, the number of science students = (50/100)(100) = 50, implying that the number of non-science students = 100-50 = 50. Since 30% of the 50 science students score more than 80%, the number of science students who ...”
September 29, 2018
Brent@GMATPrepNow posted a reply to List M consists of 50 decimals, each of which has a value be in the Problem Solving forum
“Let''s examine the EXTREME CASES S - T = x percent of T So, S - T = (x/100)T Divide both sides by to get: (S - T)/T = x/100 Multiply both sides by 100 to get: x = 100(S - T)/T First, we we''ll MINIMIZE the value of x by minimizing the value of S - T and maximizing the value of T. This ...”
September 29, 2018
Brent@GMATPrepNow posted a reply to If a child flips a coin five times in a row, what is the in the Problem Solving forum
“If a coin is flipped 5 times in a row, there are 32 possible outcomes (HHTTH, HTHTT, TTTTT, etc) How did we get 32? Well, there are 2 possible outcomes for the 1st coin flip, 2 possible outcomes for the 2nd coin flip, 2 outcomes for the 3rd flip, 2 outcomes for the 4th flip, and 2 outcomes for ...”
September 29, 2018
GMATGuruNY posted a reply to A garden center sells a certain grass seed in 5-pound bags in the Problem Solving forum
“5-pound bags = ($13.85)/5 ≈$3 per pound. 10-pound bags = ($20.43)/10 = more than$2 per pound. 25-pound bags = ($32.25)/25 = less than$1.50 per pound. To minimize the cost, we must maximize the number of 25-pound bags, which offer seed at the lowest price per pound. Two 25-pound bags = 50 ...”
September 29, 2018
Brent@GMATPrepNow posted a reply to R and S can complete a certain job in 6 and 4 days in the Problem Solving forum
“Let''s assign a "nice" value to the job, a value that works well with the given values (6 days and 4 days ). So, let''s say the ENTIRE job is to make 24 widgets R can complete a certain job in 6 days In other words, R can make 24 widgets in 6 days So, R can make 4 widgets per day ...”
September 28, 2018
GMATGuruNY posted a reply to Which of the following equations is NOT equivalent to in the Problem Solving forum
“If we plug y=-3 into 4x² = y²-9, we get: 4x² = (-3)² - 9 4x² = 0 x = 0. Test x=0 and y=-3 in the answer choices. When the question stem includes the phrase which of the following, the correct answer is likely to be D or E. D: 2x = y-3 Plugging in x=0 and y=-3, we get: 2*0 = -3-3 0 = ...”
September 28, 2018
GMATGuruNY posted a reply to If non- negative integers n & p are not both odd, in the Problem Solving forum
“If n=p=0, options A, B, C and D each yield a even value, indicating that these options do NOT have to be odd. Eliminate A, B, C and D. The correct answer is E.”
September 28, 2018
GMATGuruNY posted a reply to Is |x+y|<|x|+|y|? in the Data Sufficiency forum
“Since an absolute value cannot be negative, both sides of the question stem are NONNEGATIVE, enabling us to safely square the inequality: (|x+y|)²< (|x|+|y|)² x² + y² + 2xy < x² + y² + 2|x||y| xy < |xy| The resulting inequality is valid only if x and y have DIFFERENT SIGNS. ...”
September 28, 2018
Brent@GMATPrepNow posted a reply to An engagement team consists of a project manager, team in the Problem Solving forum
“For this question, let''s first ignore the restriction regarding the two consultants who refuse to work together and find the total number of different teams. Then we''ll determine how many of those teams break the rule about the two consultants. In other words, # of "good" teams = ...”
September 28, 2018
GMATGuruNY posted a reply to The shaded portion of the rectangular lot shown above in the Problem Solving forum
“ALWAYS KEEP YOUR EYES ON THE ANSWER CHOICES. C, D and E imply that the flower bed is probably a 6-8-10 triangle in which y=6, x = y+2 = 6+2 = 8, and z=10. Check whether this triangle satisfies the condition that the flower bed has an area of 24 square yards: Area of a 6-8-10 triangle = ...”
September 27, 2018
GMATGuruNY posted a reply to Anna wants to distribute chocolates among her four children in the Problem Solving forum
“Let the total number of chocolates = the LCM of the four denominators 2, 5, 6 and 12 = 60. Number of chocolates given to the four children: (1/2)(60) = 30 (1/5)(60) = 12 (1/6)(60) = 10 (1/12)(60) = 5 Total number of chocolates = 30+12+10+5 = 57. The correct answer is C.”
September 27, 2018
GMATGuruNY posted a reply to In 2004, 2,400 condos sold, 15% of the total housing units in the Problem Solving forum
“Of the units sold, non-condos constitute 85% = 85/100 = 17/20. Implication: Of every 20 units sold, 17 are non-condos, with the result that the number of non-condos must be a multiple of 17. A. 16000 B. 13600 C. 12400 D. 11200 E. 8600 Only the portion in green is a multiple of 17: ...”
September 27, 2018
Brent@GMATPrepNow posted a reply to In 2004, 2,400 condos sold, 15% of the total housing units in the Problem Solving forum
“We can also solve this with a little number sense If 15% of the units sold WERE condos, then 85% of the units sold new NOT condos. GIVEN: 2,400 represents 15% of the total housing units sold that year So, 4,800 must represent 30% of the total housing units sold that year And 9,600 must ...”
September 27, 2018
Brent@GMATPrepNow posted a reply to In 2004, 2,400 condos sold, 15% of the total housing units in the Problem Solving forum
“We can solve the question with equivalent ratios If 15% of the units sold WERE condos, then 85% of the units sold new NOT condos. So we want to determine the number of sold units that represent 85% of all units sold We''ll use the ratio: (number of units sold)/(percent of units sold) Let x = ...”
September 27, 2018
GMATGuruNY posted a reply to If the probability of Ronaldo will score at least 3 goals in in the Problem Solving forum
“Let G = at least 3 goals and NG = not at least 3 goals. Let W = win the match and NW = not win the match. Use a DOUBLE-MATRIX to organize the data: https://i.postimg.cc/JHLj6Tyr/matrix_goals_wins_0.png The probability that Ronaldo will score at least 3 goals in the match is 0.59. The ...”
September 27, 2018
GMATGuruNY posted a reply to A set of numbers has an average of 50. If the largest elemen in the Problem Solving forum
“Let S = the smallest number of L = the largest number. Since the largest number is 4 more than 3 times the smallest number, we get: L = 3S + 4 L-4 = 3S (L-4)/3 = S. Since the average is 50 -- and the numbers are not all the same -- S must be LESS THAN 50, while L must be greater than 50. ...”
September 26, 2018
GMATGuruNY posted a reply to What is the sum of the solutions of the equation (x-1)^2=|x- in the Problem Solving forum
“If we replace x-1 with a, we get: a² = |a|. The resulting equation is valid only if a -- in other words, the value of x-1 -- is equal to -1, 0, or 1: x-1 = -1 --> x=0 x-1 = 0 ---> x=1 x-1 = 1 ---> x=2 Sum of the solutions = 0+1+2 = 3. The correct answer is E.”
September 26, 2018
Brent@GMATPrepNow posted a reply to A set of numbers has an average of 50. If the largest elemen in the Problem Solving forum
“The largest element is 4 greater than 3 times the smallest element Let x = the smallest number in the set. So, 3x + 4 = the largest number in the set. So, the set looks something like this {x, ?, ?, . . . . ?, 3x+4} The key to this question is that the AVERAGE = 50 Since all of the answer ...”
September 26, 2018
Brent@GMATPrepNow posted a reply to A set of numbers has an average of 50. If the largest elemen in the Problem Solving forum
“The largest element is 4 greater than 3 times the smallest element Let x = the smallest number in the set. So, 3x + 4 = the largest number in the set. So, the set looks something like this {x, ?, ?, . . . . ?, 3x+4} The key to this question is that the AVERAGE = 50 Since all of the answer ...”
September 26, 2018
GMATGuruNY posted a reply to If H = [(x^3) - 6(x^2) - x + 30] / (x-5)and x ≠ 5, then H in the Problem Solving forum
“Let x=0, with the result that H = 30/-5 = -6. Now plug x=0 in the answers to see which yields a value of -6. Only A works: x² - x - 6 = 0² - 0 - 6 = -6. The correct answer is A.”
September 26, 2018