# It takes 10 hours to fill a pool with water, and 20 hours to drain it. If the pool is empty and the drain is open, how long would it take to fill the pool?

##### 1 Answer

May 2, 2018

It will take

#### Explanation:

If it takes

If it takes

If the pool is filling and draining at the same time, then it will only fill by the difference in these amounts.

After

So after

It will therefore take