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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 water from one outlet, flowing at a constant rate, can f ##### This topic has 3 expert replies and 0 member replies ### Top Member ## The water from one outlet, flowing at a constant rate, can f ## Timer 00:00 ## Your Answer A B C D E ## Global Stats Difficult The water from one outlet, flowing at a constant rate, can fill a swimming pool in 9 hours. The water from a second outlet, flowing at a constant rate, can fill the same pool in 5 hours. If both outlets are used at the same time, approximately what is the number of hours required to fill the pool? (A) 0.22 (B) 0.31 (C) 2.50 (D) 3.21 (E) 4.56 OA D Source: Official Guide ### GMAT/MBA Expert GMAT Instructor Joined 22 Aug 2016 Posted: 1697 messages Followed by: 28 members Upvotes: 470 BTGmoderatorDC wrote: The water from one outlet, flowing at a constant rate, can fill a swimming pool in 9 hours. The water from a second outlet, flowing at a constant rate, can fill the same pool in 5 hours. If both outlets are used at the same time, approximately what is the number of hours required to fill the pool? (A) 0.22 (B) 0.31 (C) 2.50 (D) 3.21 (E) 4.56 OA D Source: Official Guide Given that the first outlet, flowing at a constant rate, can fill a swimming pool in 9 hours, the part of the pool filled in 1 hour = 1/9; and the second outlet, flowing at a constant rate, can fill a swimming pool in 5 hours, the part of the pool filled in 1 hour = 1/5 Part of the pool filled in 1 hour if both the outlets are open = 1/9 + 1/5 = 14/45 Thus, the hours needed to fill the pool = 45/14 = 3.21 hours The correct answer: D Hope this helps! -Jay _________________ Manhattan Review Locations: Manhattan Review Mumbai | GMAT Prep New Delhi | GRE Prep Malleswaram | Vijayawada GRE Coaching | and many more... Schedule your free consultation with an experienced GMAT Prep Advisor! Click here. ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 12534 messages Followed by: 1245 members Upvotes: 5254 GMAT Score: 770 BTGmoderatorDC wrote: The water from one outlet, flowing at a constant rate, can fill a swimming pool in 9 hours. The water from a second outlet, flowing at a constant rate, can fill the same pool in 5 hours. If both outlets are used at the same time, approximately what is the number of hours required to fill the pool? (A) 0.22 (B) 0.31 (C) 2.50 (D) 3.21 (E) 4.56 OA D Source: Official Guide One approach is to assign a NICE NUMBER to the volume of the swimming pool. This number will work well with the two pieces of information (fill pool in 9 hours and fill pool in 5 hours). So, let's say that the volume of the pool is 45 gallons. The water from one outlet, flowing at a constant rate, can fill a swimming pool in 9 hours So, this outlet pumps at a rate of 5 gallons per hour The water from a second outlet, flowing at a constant rate, can fill the same pool in 5 hours. So, this outlet pumps at a rate of 9 gallons per hour If both outlets are used at the same time. . . The combined rate of both pumps = (5 gallons per hour) + (9 gallons per hour) = 14 gallons per hour Time = output/rate At 14 gallons per hour, the time to pump 45 gallons = 45/14 = 3 3/14 = 3.something Answer: D Cheers, Brent _________________ Brent Hanneson â€“ Creator of GMATPrepNow.com Use our video course along with Sign up for our free Question of the Day emails And check out all of our free resources GMAT Prep Now's comprehensive video course can be used in conjunction with Beat The GMATâ€™s FREE 60-Day Study Guide and reach your target score in 2 months! ### GMAT/MBA Expert Elite Legendary Member Joined 23 Jun 2013 Posted: 10014 messages Followed by: 494 members Upvotes: 2867 GMAT Score: 800 Hi All, This question is a standard "Work Formula" question. When you have 2 entities sharing a task, you can use the following formula to figure out how long it takes for the 2 entities to complete the task together. Work = (A)(B)/(A+B) where A and B are the individual times required to complete the task Here, we're given the rates as 9 hours and 5 hours. Using the Work Formula, we have... (9)(5)/(9+5) = 45/14 45/14 is a little more than 3.....there's only one answer that matches... Final Answer: D GMAT assassins aren't born, they're made, Rich _________________ Contact Rich at Rich.C@empowergmat.com • FREE GMAT Exam Know how you'd score today for$0

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