SOLUTION: Two inlet pipes can fill a water reservoir in 10 hours and 12 hours respectively when opened individually. If an outlet can empty the reservoir alone in 9 hours, how long will it t

Question 724060: Two inlet pipes can fill a water reservoir in 10 hours and 12 hours respectively when opened individually. If an outlet can empty the reservoir alone in 9 hours, how long will it take to fill the reservoir if all 3 pipes are opened simultaneously?
--THANKS
Answer by josmiceli(19441) (Show Source): You can put this solution on YOUR website!
Add their rates of filling and subtract the
rate of emptying to get the rate of filling
with all 3 pipes open.
( 1 reservoir filled ) / ( 10 hrs ) + ( 1 reservoir filled ) / ( 12 hrs ) - ( 1 reservoir emptied ) / ( 9 hrs )
= ( 1 reservoir filled / t hrs )
--------------------------

I'll multiply both sides by

hrs

It will take 13 hrs and 51 min to fill the reservoir
That's it unless there's a math error
check:

OK

RELATED QUESTIONS
A 400-gallon water storage tank is filled by a single inlet pipe, and two identical... (answered by stanbon)

An inlet pipe can fill a tank in 3 hours. An outlet pipe can empty the tank in 6 hours. (answered by Alan3354)

An intake pipe to a reservoir is controlled by a valve which automatically closes when... (answered by ankor@dixie-net.com,ikleyn)

An oil tank has two inlet pipes and one outlet pipe. One inlet pipe can fill the tank in... (answered by nerdybill)

a water tank can be filled in 20 hours by an inlet pipe and emptied in 25 hours by an... (answered by stanbon)

A water tank can be filled in 20 hours by an inlet pipe and emptied in 24 hours by an... (answered by sudhanshu_kmr)

A water tank can be filled in 24 hours by an inlet pipe and emptied in 30 hours by an... (answered by addingup)

A water tank can be filled in 20 hours by an inlet pipe and emptied in 25 hours by an... (answered by Alan3354,ikleyn)

An inlet pipe can fill a pool in 12 hours, and the outlet pipe can empty it in 8 hours.... (answered by josmiceli)