SOLUTION: A swimming pool can be filled by one pipe in 4 hours and emptied by another in 5 hours. The water is allowed to run for 2 hours with both pipes open and then the outlet is closed

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A swimming pool can be filled by one pipe in 4 hours and emptied by another in 5 hours. The water is allowed to run for 2 hours with both pipes open and then the outlet is closed      Log On


   

Question 752337: A swimming pool can be filled by one pipe in 4 hours and emptied by another in 5 hours. The water is allowed to run for 2 hours with both pipes open and then the outlet is closed. How long will it take the tank to fill
Answer by josgarithmetic(39614) About Me  (Show Source):
You can put this solution on YOUR website!
Filler, %2B%281%2F4%29 job per hour.
Emptier, -%281%2F5%29 job per hour.
Both pipes open at the same time, 1%2F4-1%2F5 job per hour =
5%2F20-4%2F20=1%2F20
%2B%281%2F20%29 job per hour.

Is this enough to continue solving? Rate * Time = Job.