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

Answer:

3.6 hours or 3 hours and 36 minutes.

Step-by-step explanation:

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

$\frac{1}{9} +\frac{1}{6} = \frac{5}{18}$ 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.

$1 / \frac{5}{18} = 3.6$ hours

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