When Lorenzo eats 1 slice of pizza for lunch, his total utility is 23, and when he eats 2 slices of pizza for lunch, his total utility is 42. Assuming that Lorenzo's marginal utility from eating pizza is always positive, we can infer that his total utility from eating 3 slices of pizza at lunch is:
A)greater than 42 and less than 84.
B)greater than 42 and less than 46.
C)greater than 42 and less than 61.
D)greater than 23 and less than 42.

Question

Quizplus · Accepted Answer

According to the law of diminishing marginal utility, the marginal utility of Lorenzo's third slice of pizza must be less than the marginal utility of his second slice. Since the marginal utility of his 2nd slice of pizza is 19, we know that the marginal utility of his third slice must be less than 19, implying that his total must be greater than 42 but less than 61 (= 42 + 19).

When Lorenzo Eats 1 Slice of Pizza for Lunch, His