SOLUTION: An inlet pipe on a swimming pool can be used to fill the pool in 25 hours. the drain pipe can be used to empty the pool in 30 hours. if the pool is 1/3 filled and then the inlet pi

Question 909513: An inlet pipe on a swimming pool can be used to fill the pool in 25 hours. the drain pipe can be used to empty the pool in 30 hours. if the pool is 1/3 filled and then the inlet pipe and drain pipe are opened, how long from that time will it take to fill the pool.
Answer by stanbon(75887) (Show Source): You can put this solution on YOUR website!
An inlet pipe on a swimming pool can be used to fill the pool in 25 hours. the drain pipe can be used to empty the pool in 30 hours. if the pool is 1/3 filled and then the inlet pipe and drain pipe are opened, how long from that time will it take to fill the pool.
-----------------
Fill Rate:: 1/25 job/hr
Empty Rate:: 1/30 job/hr
----
Combined Rate:: (1/25)-(1/30) = 5/(25*30) = 1/(5*30) = 1/150 job/hr
----
Equation:
rate*time = work done
(1/150)x = 2/3 job
----
x = 100 hrs (time to fill (2/3) of the pool.
Cheers,
Stan H.
---------------
RELATED QUESTIONS
An inlet pipe on a swimming pool can be used to fill a pool in 36 hours. The drain pipe... (answered by josgarithmetic)

an inlet pipe on a swimming pool can be used to fill a pool in 32 hours. The drain pipe... (answered by solver91311,lwsshak3)

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 32 hours. The drain pipe (answered by josgarithmetic)

an inlet pipe on a swimming pool can be used to fill the pool in 10 hours. The drain pipe (answered by mananth)

An inlet pipe on a swimming pool can be used to fill the pool in 16 hours. The drain pipe (answered by josgarithmetic,MathTherapy)

An inlet pipe on a swimming pool can be used to fill the pool in 38 hours. The drain pipe (answered by josgarithmetic)

An inlet pipe on a swimming pool can be used to fill the pool in 36 hours. The drain pipe (answered by josmiceli)

An inlet pipe on a swimming pool can be used to fill the pool in 10 hours. The drain pipe (answered by josgarithmetic)