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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 ## An empty pool being filled with water at a constant rate tagged by: BTGmoderatorRO ##### This topic has 4 expert replies and 1 member reply ## An empty pool being filled with water at a constant rate An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min OA is B what is the best mathematical approach to use here? please i need help from expert here Thanks ### GMAT/MBA Expert Senior | Next Rank: 100 Posts Joined 16 Dec 2014 Posted: 94 messages Followed by: 4 members Upvotes: 2 GMAT Score: 770 Top Reply Roland2rule wrote: An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min OA is B what is the best mathematical approach to use here? please i need help from expert here Thanks Rate = Work/Time R = (3/5)/8 = 3/40 pool per hour We need to fill 2/5 of the pool to finish the job 3/40 = (2/5)/T 3/40 = (16/40)T T = 16/3 = 5 1/3 hrs or 5 hrs and 20 min Answer is (B) 5 hr 20 min ### GMAT/MBA Expert GMAT Instructor Joined 08 Dec 2008 Posted: 12422 messages Followed by: 1244 members Upvotes: 5254 GMAT Score: 770 Roland2rule wrote: An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min Here's another approach: IMPORTANT CONCEPT: After 8 hours, 3/5 of the job is finished and 2/5 of the job is remaining. This means the remaining part of the job is 2/3 the size of the first part of the job. Think of it this way: If the pool had a capacity of 5 gallons, then the first part of the job would be filling 3 gallons, and the remaining part of the job is filling 2 gallons. So, the remaining part of the job (filling 2 gallons) is 2/3 the size of the first part of the job (filling 3 gallons) So, if it takes 8 hours to do the first part of the job, the time to do the remaining part = 2/3 of 8 hours 2/3 of 8 hours = 2/3 x 8 hours = 16/3 hours = 5 1/3 hours = 5 hours 20 minutes Answer: B _________________ 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: 9942 messages Followed by: 492 members Upvotes: 2867 GMAT Score: 800 Hi Roland2rule, We're told that 8 hours fills 3/5 of the pool; the question asks how long it will take to fill the remaining 2/5 of the pool. Since the pool is filling at a constant rate, we can use a ratio to answer the question. The ratio can be written in a number of different ways; I used the following ratio: 8/X = (3/5)/(2/5) Simplifying, we getâ€¦ 8/X = 3/2 Now, cross-multiplyâ€¦ 3X = 16 X = 5 1/3 hours 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: 680 messages Followed by: 4 members Hi, As the pool is filled at a constant rate, you can solve it as follow, 8 hours....................................................... 3/5 X hours....................................................... 2/5 Then, $$X=\frac{8\cdot\frac{2}{5}}{\frac{3}{5}}=\frac{16}{3}=5.33\ hours$$ X = 5 hours and 20 minutes. Option B. Regards! ### GMAT/MBA Expert GMAT Instructor Joined 25 Apr 2015 Posted: 1776 messages Followed by: 14 members Upvotes: 43 Roland2rule wrote: An empty pool being filled with water at a constant rate takes 8 hours to fill to 3/5 of its capacity. How much more time will it take to finish filling the pool? (A) 5 hr 30 min (B) 5 hr 20 min (C) 4 hr 48 min (D) 3 hr 12 min (E) 2 hr 40 min We can let n = the time it takes to fill the remaining 2/5 of the pool and create the proportion: 8/(3/5) = n/(2/5) 40/3 = 5n/2 80 = 15n n = 80/15 = 16/3 = 5 1/3 hours = 5 hours and 20 minutes Answer: B _________________ Scott Woodbury-Stewart Founder and CEO • FREE GMAT Exam Know how you'd score today for$0

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