Question 276432: if it takes 10 hours to fill a pool and 20 hours to drain it, how long will it take to fill it if the drain is open? Answer by mananth(16946) (Show Source):
You can put this solution on YOUR website! if it takes 10 hours to fill a pool and 20 hours to drain it, how long will it take to fill it if the drain is open?
It fills 1/10th. of the pool in one hour
It drains 1/20th of the pool in 1 hour.
In an hour actually the increase is 1/10-1/20
1/20
with the drain open 1/20th of the pool is filled in one hour.
so to fill the pool it will take 20 hours
