Question

One pipe can fill a pool in 9 hours. Another pipe can fill the pool in 6 hours. How long would it take them to fill the pool if they were working together?

Answer 1

3.6 hours or 3 hours and 36 minutes.

Explanation:

If the first pipe can fill the pool in 9 hours that means that in 1 hour it fills
`(1)/(9)` of the pool, we use the same logic for the second pipe and conclude that in 1 hour it feels up
`(1)/(6)` of the pool. If both were to fill the pool together that means that in 1 hour they would fill...

`(1)/(9) +(1)/(6) = (5)/(18)` of the pool in 1 hour.

Now to find how many hours it will take divide the pool by the speed with which it is getting filled.

`1 / (5)/(18) = 3.6` hours

3.6 hours in other words is 3 hours and 36 minutes.