SOLUTION: It take one pipe 3 hours to fill the pool and a second pipe 4 hours to drain a pool. The pool is empty and the first pipe begins to fill it. The second pipe is accidentally left op

Question 743970: It take one pipe 3 hours to fill the pool and a second pipe 4 hours to drain a pool. The pool is empty and the first pipe begins to fill it. The second pipe is accidentally left open, so the water is also draining out of the pool. Under these conditions how long will it take to fill the pool?
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add the rate of filling and subtract the rate
of draining.
Let = time in hrs to fill pool with both pipes open
( 1 pool filled ) / ( 3 hrs ) - ( 1 pool emptied ) / ( 4 hrs ) = ( 1 pool filled ) / ( t hrs )

Multiply both sides by

It will take 12 hrs to fill the pool
RELATED QUESTIONS
One inlet pipe can fill an empty pool in 4 hours, and a drain can empty the pool in 8... (answered by josmiceli)

one inlet pipe can fill an empty pool in 4 hours, and a drain can empty the pool in 8... (answered by Alan3354)

One inlet pipe can fill an empty pool in 4 hours, and a drain can empty the pool in 10... (answered by stanbon,mananth)

One pipe fills a pool in 4 hours. A second pipe, used to drain the water from the pool,... (answered by richwmiller)

One inlet pipe can fill an empty pool in 6 hours, and a drain can empty the pool in 9... (answered by ewatrrr)

One inlet pipe can fill an empty pool in 8 hours, and a drain can empty the pool in 16... (answered by josgarithmetic)

One inlet pipe can fill an empty pool in 6 hours, and a drain can empty the pool in 10... (answered by greenestamps,josgarithmetic)

An inlet pipe on a swimming pool can be used to fill the pool in 23 hours. The drain pipe (answered by mananth)

An inlet pipe on a swimming pool can be used to fill the pool in 18 hours. The drain pipe (answered by josgarithmetic)