SOLUTION: A large pump can filla 77,000 gallon reservoir in 7 hours. Working together, the large pump and a smaller one can fill the reservoir in 6 hours. How long would it take the smaller

Algebra ->  Rate-of-work-word-problems -> SOLUTION: A large pump can filla 77,000 gallon reservoir in 7 hours. Working together, the large pump and a smaller one can fill the reservoir in 6 hours. How long would it take the smaller       Log On


   



Question 191641: A large pump can filla 77,000 gallon reservoir in 7 hours. Working together, the large pump and a smaller one can fill the reservoir in 6 hours. How long would it take the smaller pump to fill the reservoir by itself?
Answer by orca(409) About Me  (Show Source):
You can put this solution on YOUR website!
Let x represent the amount of water the smaller pump can pump per hour.
The amount of water the larger pump can pump per hour is 77000/7 = 11000 gallons/h.
Working together the number of gallons of water they can pump each hour is
11000 + x.
As they can fill the reservoir in 6 hours, we have
6(11000+x)=77000
Solving for x, we have
11000 + x = 77000/6
x = 77000/6-11000
x = 77000/6-66000/6 = 11000/6
Therefore the amount of water the smaller pump can pump per hour is 11000/6.
So the time it takes for the smaller pump to fill the reservoir is
77000%2F%2811000%2F6%29=+77000%2A6%2F11000=+42 hours.