Right next door to where Mitch was taking trumpet lessons was a massage parlor offering massages for the exact same price as trumpet lessons. Cam believes Mitch has been practicing the trumpet for two years now, but it turns out that Mitchell has just been getting regular massages. Utility maximization assumes that when two items are the same price, consumers will chose the item with the higher utility. While Mitch originally thought he wanted to learn how to play the trumpet, he realized each additional massage generated higher levels of utility than another trumpet lesson.
See more: equimarginal principle, marginal utility, substitutes, utility, utility maximization
Economics of Modern Family 