Sean is spending the day at the water park. He paid to enter the park and can use any water ride an unlimited number of times throughout the day. His favorite ride is the Twisty River.

a. Sean's marginal utility of riding the Twisty River the first time is 50 utils. Sean's marginal utility of riding the Twisty River the second time is likely
O greater than 50 utils.
O less than 50 utils.
O equal to 50 utils

b. If Sean's total utility begins to decrease after his fifth ride on the Twisty River, we can conclude
O Sean's marginal utility is starting to increase.
O Sean's marginal utility has become negative.
O Sean has maximized his marginal utility

c. Suppose instead of an entrance fee that Sean must pay each time he rides the Twisty River. Compared to the entrance fee, Sean will likely ride the Twisty River
O fewer times
O more times.
O the same number of times.

Utility is the satisfaction derived from consuming a good or service. Marginal Utility is the added satisfaction a consumer gets when he/she consumes an additional unit while the total utility is the sum of how satisfied he/she is after consuming a given number of units.

Marginal utility reduces with every extra unit taken. So Sean's marginal utility of riding the Twisty River the second time is likely less than that of the first time. Consider when you are very thirsty and you take the first sip of water. This is the most satisfying sip and the last one you take is the least satisfying.

As long as marginal utility is positive, total utility will increase. Imagine Sean gets a marginal utility of 50, 40, 30 and 10. The total utility is then 50, 90, 120 and 130 after every ride. If after the fifth ride, his total utility is 115, it means his marginal utility has become negative (maybe he threw up).

Because marginal utility reduces with every additional unit taken, Sean is not likely to keep spending the same amount of money when he is not getting the same amount of satisfaction so he will likely ride the Twisty River fewer times.