A plumbing contractor decides to field-test two new pumps. One is rated at 100 gal/h and the other at 130 gal/h. She tests one, then the other. Over a period of 11 h, she pumps a total of 1,190 gal. Assume both pumps operated as rated. How long is each in operation?
A) The first pump is in operation 8 h,
The second pump is in operation 4 h.
B) The first pump is in operation 3 h,
The second pump is in operation 8 h.
C) The first pump is in operation 16 h,
The second pump is in operation 3 h.
D) The first pump is in operation 8 h,
The second pump is in operation 3 h.
E) The first pump is in operation 8 h,
The second pump is in operation 2 h.

Question

Quizplus · Accepted Answer

Let x be the number of hours the first pump is in operation and y be the number of hours the second pump is in operation.

We know that:

x + y = 11 (total time pumping)
100x + 130y = 1190 (total gallons pumped)

Solving this system of equations gives:

x = 8
y = 3

Therefore, the first pump is in operation for 8 hours and the second pump is in operation for 3 hours. So, choice D is correct.

A Plumbing Contractor Decides to Field-Test Two New Pumps