SOLUTION: A pump can fill an oil tank in 18 hours. Beginning with an empty tank, the pump and a second pump fill three-fifths of the tank in 6 hours. If the first pump is then shut off, how

Algebra ->  Systems-of-equations -> SOLUTION: A pump can fill an oil tank in 18 hours. Beginning with an empty tank, the pump and a second pump fill three-fifths of the tank in 6 hours. If the first pump is then shut off, how       Log On


   

Question 1108048: A pump can fill an oil tank in 18 hours. Beginning with an empty tank, the pump and a second pump fill three-fifths of the tank in 6 hours. If the first pump is then shut off, how long will it take the second pump to finish filling the tank?
Answer by josgarithmetic(39616) About Me  (Show Source):
You can put this solution on YOUR website!
Pump 1
18 hours to fill 1 tank

Pump 1 plus Pump 2
6 hours to fill 3%2F5 tank

Pump 2
x unknown hours to fill 1 tank

1%2F18%2B1%2Fx=%283%2F5%29%2F6------solve to find the time for just pump #2 to fill 1 tank-ful by itself.

1%2F18%2B1%2Fx=1%2F10, LCD is 180x,...
.
.
x=22%261%2F2-------hours for pump #2 to fill 1 tank.


The question means, how much time for pump #2, to fill 2%2F5 of the tank.