SOLUTION: A hose can fill a pool in 12 hours. A drainage pipe can empty the pool in 18 hours. If the drain pipe is left open while the pool is filling how long will it takes to fill a pool?

Question 962365: A hose can fill a pool in 12 hours. A drainage pipe can empty the pool in 18 hours. If the drain pipe is left open while the pool is filling how long will it takes to fill a pool?

Answer by ptaylor(2198) (Show Source): You can put this solution on YOUR website!
Let x= amount of time for pool to fill
with both pipes open the pool fills at the rate of 1/x pool per hour
Hose fills at rate of 1/12 pool per hour
Drainage pipe empties at rate of 1/18 pool per hour
sooo
1/12 - 1/18= 1/x multiply each term by 36x to get rid of fractions
3x-2x=36
x=36 hours ---
CK
In 36 hours fill pipe fills (1/12)*36= 3 pools
In 36 hours drain pipe drains(1/18)*36=2 pools
3-2=1 full pool:)
hope this helps--- ptaylor
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