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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 ## Two hoses are pouring water into an empty pool. Hose 1 alone tagged by: AAPL ##### This topic has 3 expert replies and 1 member reply ### Top Member ## Two hoses are pouring water into an empty pool. Hose 1 alone ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult Manhattan Prep Two hoses are pouring water into an empty pool. Hose 1 alone would fill up the pool in 6 hours. Hose 2 alone would fill up the pool in 4 hours. How long would it take for both hoses to fill up two-thirds of the pool? A. 5/12 hours B. 5/8 hours C. 8/5 hours D. 12/7 hours E. 12/5 hours OA C ### GMAT/MBA Expert GMAT Instructor Joined 25 May 2010 Posted: 15344 messages Followed by: 1864 members Upvotes: 13060 GMAT Score: 790 AAPL wrote: Manhattan Prep Two hoses are pouring water into an empty pool. Hose 1 alone would fill up the pool in 6 hours. Hose 2 alone would fill up the pool in 4 hours. How long would it take for both hoses to fill up two-thirds of the pool? A. 5/12 hours B. 5/8 hours C. 8/5 hours D. 12/7 hours E. 12/5 hours Let the pool = 12 gallons. Since Hose 1 takes 6 hours to fill the 12-gallon pool, the rate for Hose 1 = w/t = 12/6 = 2 gallons per hour. Since Hose 2 takes 4 hours to fill the 12-gallon pool, the rate for Hose 2 = w/t = 12/4 = 3 gallons per hour. Since the combined rate for the two hoses = 2+3 = 5 gallons per hour, the time to fill 2/3 of the 12-gallon pool = w/r = (2/3 * 12)/5 = 8/5 hours. The correct answer is C. _________________ 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. ### Top Member Legendary Member Joined 29 Oct 2017 Posted: 958 messages Followed by: 4 members Time taken by H1 =6, W=1, R1=1/6 Time taken by H2=4, w=1, R2 =1/4 so together R1+R2 =1/6+1/4= 5/12 and w=2/3, t = w/(R1+R2) = 2/3 *12/5 = 8/5 ### GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 2791 messages Followed by: 18 members Upvotes: 43 AAPL wrote: Manhattan Prep Two hoses are pouring water into an empty pool. Hose 1 alone would fill up the pool in 6 hours. Hose 2 alone would fill up the pool in 4 hours. How long would it take for both hoses to fill up two-thirds of the pool? A. 5/12 hours B. 5/8 hours C. 8/5 hours D. 12/7 hours E. 12/5 hours OA C We see that the rate of hose 1 is 1/6, and the rate of hose 2 is 1/4. We can let x = time needed to fill 2/3 of a pool when they work together and create the equation: 1/6(x) + 1/4(x) = 2/3 Multiplying the equation by 12, we have: 2x + 3x = 8 5x = 8 x = 8/5 hours Answer: C _________________ 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 Elite Legendary Member Joined 23 Jun 2013 Posted: 10197 messages Followed by: 496 members Upvotes: 2867 GMAT Score: 800 Hi All, This question is a variation of a 'Work Formula' question (it involves 2 'entities' working on the same task together), so we can use the Work Formula to solve it. Work = (A)(B)/(A+B) where A and B are the individual times that it takes the 2 entities to complete the task on their own. Here, we're told that Hose 1 can fill a pool in 6 hours and that Hose 2 can fill the pool in 4 hours. We're asked how long it takes the two hoses to fill 2/3 of the pool... To fill the ENTIRE POOL, it takes... (6)(4)/(6+4) = 24/10 = 2.4 hours To fill 2/3 of the pool takes 2/3 of the time. Since 2.4 hours = 12/5 hours, it would take... (2/3)(12/5) = 24/15 = 8/5 hours to fill 2/3 of the pool. Final Answer: C GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • Magoosh Study with Magoosh GMAT prep Available with Beat the GMAT members only code • 5-Day Free Trial 5-day free, full-access trial TTP Quant Available with Beat the GMAT members only code • 5 Day FREE Trial Study Smarter, Not Harder Available with Beat the GMAT members only code • Free Trial & Practice Exam BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • 1 Hour Free BEAT THE GMAT EXCLUSIVE Available with Beat the GMAT members only code • Free Veritas GMAT Class Experience Lesson 1 Live Free Available with Beat the GMAT members only code • Get 300+ Practice Questions 25 Video lessons and 6 Webinars for FREE Available with Beat the GMAT members only code • FREE GMAT Exam Know how you'd score today for$0

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