Question

A pool can be filled in 45 hours and drained in 60 hours. How many hours will it take to fill the pool if both the fill and drain pipes are on?

Answer 1

it will take 180 hours to fill the pool if both the fill and drain pipes are on

Explanation:

A pool can be filled in 45 hours → the water can fill
`(1)/(45)` pool per hour

A pool can be drained in 60 hours → the water can drain
`(1)/(60)` pool per hour

Therefore, if both the fill and drain pipes are on, it can fill the pool by
`(1)/(45) -(1)/(60) =(1)/(180)` pool per hour

It will take
`1/(1)/(180)` = 180 hours to fill the pool