SOLUTION: A pool can be filled in 45 hours and drained in 60 hours. How long will it take to fill the pool if both the fill and drain pipes are on? Enter your answer to the nearest hour. (En

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A pool can be filled in 45 hours and drained in 60 hours. How long will it take to fill the pool if both the fill and drain pipes are on? Enter your answer to the nearest hour. (En      Log On


   

Question 610599: A pool can be filled in 45 hours and drained in 60 hours. How long will it take to fill the pool if both the fill and drain pipes are on? Enter your answer to the nearest hour. (Enter only the numerical value)
Found 2 solutions by scott8148, dfrazzetto:
Answer by scott8148(6628) About Me  (Show Source):
You can put this solution on YOUR website!
in 45hr, enough water has been put in to fill the pool; but 3/4 of it (45/60) has drained out

so if it takes 45 hr to fill 1/4; how long to fill the whole pool?

Answer by dfrazzetto(283) About Me  (Show Source):
You can put this solution on YOUR website!
Assume 45 gallon pool (just to get a rate)
fill rate = 45 gallons / 45 hours = 1 gal/hr
drain rate = 45 gallons / 60 hours = .75 gal/hr
NET FILL RATE = fill rate - drain rate = .25 gal / hr
Time to fill pool w/ both pipes on = 45 gallons / .25 gal / hr
180 hours