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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 A paint crew gets a rush order to paint 80 houses in a new d This topic has 2 expert replies and 1 member reply Top Member A paint crew gets a rush order to paint 80 houses in a new d Timer 00:00 Your Answer A B C D E Global Stats Difficult A paint crew gets a rush order to paint 80 houses in a new development. They paint the first y houses at a rate of x houses per week. Realizing that they'll be late at this rate, they bring in some more painters and paint the rest of the houses at the rate of 1.25x houses per week. The total time it takes them to paint all the houses under this scenario is what fraction of the time it would have taken if they had painted all the houses at their original rate of x houses per week? (A) 0.8(80 - y) (B) 0.8 + 0.0025y (C) 80/y - 1.25 (D) 80/1.25y (E) 80 - 0.25y OA B Source: Official Guide 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, We're told that a paint crew gets a rush order to paint 80 houses in a new development. They paint the first Y houses at a rate of X houses per week. Realizing that they'll be late at this rate, they bring in some more painters and paint the rest of the houses at the rate of 1.25X houses per week. We're asked to find the total time it takes them to paint all the houses under this scenario as a fraction of the time it would have taken if they had painted all the houses at their original rate of X houses per week. This question can be solved in a number of different ways, including by TESTing VALUES (and the answer choices are written in such a way that you don't have to do too much math overall to answer the question). To start, we should choose a value for X that will work well with 1.25X. Let's choose X = 4 (so 1.25X = 5). In addition, we should look to choose a value for Y that will leave a remaining number of house that will be a multiple of 5... Let's TEST... X = 4 Y = 20 For the first 20 houses, painting 4 houses/week will take 20/4 = 5 weeks. For the remaining 60 houses, painting 5 houses/week will take 60/5 = 12 weeks. Total time = 5 + 12 = 17 weeks At the original rate, the 80 houses would take 80/4 = 20 weeks. Thus, we're looking for a fraction that equals 17/20 = .85.... notice how that answer is a number that is LESS than 1. Considering how the answer choices are written, and that our Y = 20, you should be able to eliminate all of the wrong answers without doing too much math... Answer A: (.8)(60) --> greater than 1 Answer B: (.8) + a tiny decimal --> exactly what we're looking for! Answer C: 80/20 - 1.25 --> a little less than 3 Answer D: (80)/(1.25)(20) = 80/25 --> greater than 1 Answer E: (80) - (.25)(20) --> greater than 1 Final Answer: B GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com Top Member Legendary Member Joined 29 Oct 2017 Posted: 975 messages Followed by: 4 members Top Reply original time = 80/x weeks new time = y/x + (80-y)/1.25x ratio=y/x + (80-y)/1.25x : 80/x = 1.25y+80 - y:100 = 0.25y+80:100 ratio = 0.8 0.0025y GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15362 messages Followed by: 1866 members Upvotes: 13060 GMAT Score: 790 BTGmoderatorDC wrote: A paint crew gets a rush order to paint 80 houses in a new development. They paint the first y houses at a rate of x houses per week. Realizing that they'll be late at this rate, they bring in some more painters and paint the rest of the houses at the rate of 1.25x houses per week. The total time it takes them to paint all the houses under this scenario is what fraction of the time it would have taken if they had painted all the houses at their original rate of x houses per week? (A) 0.8(80 - y) (B) 0.8 + 0.0025y (C) 80/y - 1.25 (D) 80/1.25y (E) 80 - 0.25y Let y=0, implying that NONE of the 80 houses are painted at the original rate of x houses per week, with the result that ALL 80 houses are painted at the greater rate of (5/4)x houses per week. The total time it takes them to paint all the houses under this scenario is what fraction of the time it would have taken if they had painted all the houses at their original rate? Time and rate have a RECIPROCAL RELATIONSHIP. Since the rate for painting all 80 houses is 5/4 the original rate, the time for painting all 80 houses is 4/5 of the original time. The correct answer must yield 4/5 when y=0. Only B works: 0.8 + 0.0025y = 0.8 = 4/5. The correct answer is B. _________________ Mitch Hunt Private Tutor for the GMAT and GRE GMATGuruNY@gmail.com If you find one of my posts helpful, please take a moment to click on the "UPVOTE" icon. Available for tutoring in NYC and long-distance. For more information, please email me at GMATGuruNY@gmail.com. Student Review #1 Student Review #2 Student Review #3 Free GMAT Practice Test How can you improve your test score if you don't know your baseline score? Take a free online practice exam. Get started on achieving your dream score today! Sign up now. • FREE GMAT Exam Know how you'd score today for$0

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