Company C has a machine that, working alone at its constant rate, processes 100 units of a certain product in 5 hours. If Company C plans to buy a new machine that will process this product at a constant rate and if the two machines, working together at their respective constant rates, are to process 100 units of this product in 2 hours, what should be the constant rate, in units per hour, of the new machine?

A. 50

B. 45

C. 30

D. 25

C. 30

Explanation:

If the first machine processes 100 units in 5 hours,

Number of units in 1 hour = 100/5

= 20 Units

In 2 hours, this machine would process

= 2 * 20

= 40 Units

Therefore where there are 100 units to be processed in 2 hours, the first machine would process 40 units in the given time

The new machine would have to process the remaining

Number of units to be processed by new machine

= 100 - 40

= 60 Units

If the machine is to process 60 units in 2 hours, constant rate, in units per hour, of the new machine

= 60/2

= 30 units per hour