Question

A medium water hose can fill a pool in 30 minutes. A larger water hose can fill the same pool in 20 minutes. If both hoses are turned on at the same time, how long will it take to fill the pool?

Answer 1

it will take 12 minutes for both hioses to fill the pool

Answer 2

It will take 12 hours:

1/30 + 1/20 = 1/x

.083333333=1/x

x=1/.08333333

x=12 minutes