Suppose you are eating buffalo wings at a local happy hour. The total utils from doing so after the fourth, fifth, sixth, and seventh wings are 80, 116, 136, 150, respectively. The marginal utility of the sixth wing is utils.

The marginal utility of the sixth wing is 20 utils (136 - 116).

Explanation:

a) Calculation of Marginal Utility from the buffalo wings case:

No. of wings        Total utils     Marginal Utility

4th                         80                

5th                         116                 36 (116 - 80)

6th                        136                 20 (136 - 116)

7th                        150                 14 (150 - 136)

b) In economics, utility is the satisfaction or benefit derived by consuming a product.  Marginal utility is the quantification of the added satisfaction or benefit a consumer derives from consuming additional units of the goods or services.  Economists use the concept to determine how much of an item consumers are willing to purchase (effective demand).

It can be seen that after consuming the first product, the marginal utility of a good or service continues to reduce until it gets to a point where you can identify that no more utility is being derived by the consumer from continued consumption of the particular good or service.  That is, there is a point at which the marginal utility levels out to zero and even becomes negative.