SOLUTION: An inlet pipe can fill a tank in 6 minutes. A drain can empty the tank in 9 minutes. If the tank is empty, and both the pipe and drain are open, how long will it take before the ta

Algebra ->  Rate-of-work-word-problems -> SOLUTION: An inlet pipe can fill a tank in 6 minutes. A drain can empty the tank in 9 minutes. If the tank is empty, and both the pipe and drain are open, how long will it take before the ta      Log On


   



Question 910530: An inlet pipe can fill a tank in 6 minutes. A drain can empty the tank in 9 minutes. If the tank is empty, and both the pipe and drain are open, how long will it take before the tank overflows?
Answer by richwmiller(17219) About Me  (Show Source):
You can put this solution on YOUR website!
1/a+1/b=1/x
1/6+1/-9=1/x
-9/-54+6/-54=1/x
-3/-54=1/x
x=-54/-3
x=18 minutes working together
check
x/a+x/b=1
x/6+x/-9=1
18/6+18/-9=1
3+-2=1
1=1
ok