Answer:
$24 is the marginal cost of producing the third unit of output.
Explanation:
We know that the average variable cost of producing 3 units is 32, if we multiply 32 by 3 we get the total variable cost of producing 3 units. So 96 is the total variable cost of producing 3 units. Now we know that the marginal cost of producing the firs unit is 40 and the second unit is 32 so we can subtract (32+40) from 96 to find the marginal cost of the third unit.
96-(32+40)=24