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 [tex]\frac{1}{9}[/tex] of the pool, we use the same logic for the second pipe and conclude that in 1 hour it feels up [tex]\frac{1}{6}[/tex] of the pool. If both were to fill the pool together that means that in 1 hour they would fill...
[tex]\frac{1}{9} +\frac{1}{6} = \frac{5}{18}[/tex] 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.
[tex]1 / \frac{5}{18} = 3.6[/tex] hours
3.6 hours in other words is 3 hours and 36 minutes.
