A large pump can fill a 73,000 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?

Question

Quizplus · Accepted Answer

Let's assume that the small pump can fill the tank in x hours. Then we can write the following equation:
1/7 + 1/x = 1/6
Multiplying both sides by 42x, we get:
6x + 42 = 7x
x = 42
Therefore, the small pump can fill the reservoir by itself in 42 hours.

A Large Pump Can Fill a 73,000 Gallon Reservoir in 7