If the units of a variable input in a production process are 1, 2, 3, 4 and 5, and the corresponding total outputs are: 30, 43, 58, 66 and 72. The arc marginal product of the fourth unit of input is:
A) 4
B) 6
C) 8
D) 10
E) 12

Question

Quizplus · Accepted Answer

The arc marginal product of the fourth unit of input is the change in output when moving from using 3 units of input to using 4 units of input. 
The total output with 3 units of input is 58. 
The total output with 4 units of input is 66. 
Therefore, the change in output when moving from 3 units of input to 4 units of input is 66-58=8. 
Therefore, the arc marginal product of the fourth unit of input is 8.

If the Units of a Variable Input in a Production