Question

A swimming pool can be filled in 18 hours if water enters through a pipe​ alone, or in 25 hours if water enters through a hose alone. If water is entering through both the pipe and the​ hose, how long will it take to fill the pool
5/6 ​full?

Answer 1

I am not sure, but this is what I got:
 Pipe ALONE = 18 hours 

Pipe ALONE in 1 hour = 1/18 of the pool 

Hose ALONE in 1 hour = 1/25 of the pool 

TOGETHER in 1 HOUR = 1/18 +1/25 = 43/450 

TOGETHER they will fill the pool in 450/43 hours 

So 5/6 of the pool will take 5/6 X 450/43 = 2250/ 258 = 8.7209302 hours OR 

8 hours AND 43.26 minutes ANSWER

Hope this helps!