Hello,Originally Posted bypochoa

I'm very sorry, but your answer couldn't be right because one hose needs a lot more time to fill the swimmingpool than both hoses together.

Let's have another try:

(I use SP as abbreviation for "swimmingpool")

Bob's hose needs b hours to fill the SP.

Jim's hose needs j hours to fill the SP.

That means:

Bob's hose delivers per hour.

Jim's hose delivers per hour.

Both hosestogetherdelivers per hour.

They need 18 hours to fill the SP:

Expanded:

Divide both sides of the equation by SP and you get:

As we know that we can substitute b by j:

I leave the next steps to you.

As the final result you'll get b=32.4 hrs (32 h; 24 min) and j = 40.5 hrs (40 h; 30 min).

Bye