It would take one machine 4 hours to complete a production order and another machine 2 hours to complete the same order....

Question

It would take one machine 4 hours to complete a production order and another machine 2 hours to complete the same order. If both machines work simultaneously at their respective constant rates, the time taken to complete the same order is ________ hours.

A. 2/3
B. 3/4
C. 4/3
D. 7/3

Accepted Answer

4/3 hours, which matches option C. Two machines can each independently complete the same production order, but at different speeds. Machine 1 needs 4 hours alone while Machine 2 needs only 2 hours. When both run at the same time, their rates add together, so the job gets done faster than either machine could alone. We need to find this combined completion time.

It would take one machine 4 hours to complete a production order and another machine 2 hours to complete the same order. If both machines work simultaneously at their respective constant rates, the time taken to complete the same order is ________ hours. A. 2/3 B. 3/4 C. 4/3 D. 7/3