It takes 12 hours to fill a pool with the inlet pipe. it can be emptied in 15 hours with the outlet pipe. if the pool is 2 3 full to begin with, how long will it take to fill it from there if both pipes are open?

20 hour

Step-by-step explanation:

Let the total capacity of the pool is 100%

It is given that 2/3 of the pool is already filled means % is already filled

So 100%-66.66%= 33.33 % pipe is empty

it is given that it takes 12 hours to fill the pool so inlet rate is

It is also given that it can empty in 15 hours so outlet rate is So equivalent rate for filling the pool is %

So time required to fill the pool is hour