Answer:
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
pool per hour
A pool can be drained in 60 hours → the water can drain
pool per hour
Therefore, if both the fill and drain pipes are on, it can fill the pool by
pool per hour
It will take
= 180 hours to fill the pool