Question

An inlet pipe on a swimming pool can be used to fill the pool in 33 hours. The drain pipe can be used to empty the pool in 34 hours. If the pool is
`(2)/(3)` filled and then the inlet pipe and drain pipe are opened, how many more hours would it take to fill the pool? Round your answer to two decimal places, if needed.

Answer 1

• 374 hours

Explanation:

• Filling rate is 1/33
• Draining rate is 1/34

The difference is the filling rate with both lines open:

• 1/33 - 1/34 = 1/1122

The pool is 2/3 full and needs filling the remainder, 1/3.

Time required to fill:

• 1/3 : 1/1122 = 1122/3 = 374 hours