Question

One pipe can fill a swimming pool in 8 hours.
Another pipe takes 12 hours. How long will it take to fill the pool if both pipes are used simultaneously?

Answer 1

Pipe A will fill 1/8 of the pool is 1 hour. Pipe B will fill 1/12 of the pool in 1 hour.

So, 1/8 + 1/12 = 5/24

It will take 4.8 hours to fill the pool.

Answer 2

it will fill it in 24 hours, because 1/8-1/12= 1/24. So it will be 24 hours. We are subtracting, the two because the water is draining out at the same time.