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100 points for $49 worth of Veritas practice GMATs FREE VERITAS PRACTICE GMAT EXAMS Earn 10 Points Per Post Earn 10 Points Per Thanks Earn 10 Points Per Upvote ## The R students in a class agree to contribute equally to buy ##### This topic has 3 expert replies and 0 member replies ### Top Member ## The R students in a class agree to contribute equally to buy ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult The R students in a class agree to contribute equally to buy their teacher a birthday present that costs y dollars. If x of the students later fail to contribute their share, which of the following represents the additional number of dollars that each of the remaining students must contribute in order to pay for the present? (A) y/R (B) y/(R-x) (C) xy/(R-x) (D) xy/(R(R-x)) (E) y/(R(R-x)) OA D Source: Princeton Review ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 496 members Upvotes: 2867 GMAT Score: 800 Top Reply Hi All, While this question is wordy, and will require some note-taking, it can be solved by TESTing VALUES. Let's TEST... R = 5 students Y = 50 dollars X = 3 fail to pay So the 'story' is that 5 students agree to pay an equal amount for a$50 present (that's $10 per student). We're told that 3 of them fail to pay (3 students x$10/each = $30 unpaid). Thus, the remaining 2 students have to pay an extra$30/2 = $15 each for the present. Thus, we're looking for an answer that equals 15 when R=5, Y=50 and X=3 While the answer choices look complex, there are some patterns involved: several of the calculations repeat (for example, R-X appears in 4 of the answers, so you do NOT need to calculate it 4 separate times). Since Y = 50, any answer with Y alone in the numerator can be skipped over (there is no integer that will make 50/integer = 15). That leaves two answers to TEST and just a bit of arithmetic. Final Answer: D GMAT assassins aren't born, they're made Rich _________________ Contact Rich at Rich.C@empowergmat.com ### GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2791 messages Followed by: 18 members Upvotes: 43 Top Reply BTGmoderatorDC wrote: The R students in a class agree to contribute equally to buy their teacher a birthday present that costs y dollars. If x of the students later fail to contribute their share, which of the following represents the additional number of dollars that each of the remaining students must contribute in order to pay for the present? (A) y/R (B) y/(R-x) (C) xy/(R-x) (D) xy/(R(R-x)) (E) y/(R(R-x)) OA D Source: Princeton Review The original amount of money paid is y/R The new amount of money paid is y/(R - x) The difference is: y/(R - x) - y/R yR/[R(R-x)] - y(R-x)/[R(R-x)] (yR- yR + yx)/[R(R-x)] yx/[R(R-x)] Answer: D _________________ Scott Woodbury-Stewart Founder and CEO scott@targettestprep.com See why Target Test Prep is rated 5 out of 5 stars on BEAT the GMAT. Read our reviews ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15344 messages Followed by: 1864 members Upvotes: 13060 GMAT Score: 790 BTGmoderatorDC wrote: The R students in a class agree to contribute equally to buy their teacher a birthday present that costs y dollars. If x of the students later fail to contribute their share, which of the following represents the additional number of dollars that each of the remaining students must contribute in order to pay for the present? (A) y/R (B) y/(R-x) (C) xy/(R-x) (D) xy/(R(R-x)) (E) y/(R(R-x)) Let y=$10 and R=10 students, with the result that the original share per student = ($10)/(10 students) =$1.
Let x=9, implying that the number of students decreases by 9 to 1.
New share per student = ($10)/(1 student) =$10.
Increase in share per student = 10-1 = $9. The correct answer must yield$9 when y=10, R=10 and x=9.
Only D works:
xy/(R(R-x)) = (9*10)/(10(10-9)) = 90/10 = 9.

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