To maximize utility given a budget constraint, a consumer should allocate spending such that the marginal utility per dollar spent on each good is equal to the marginal utility per dollar spent on other goods. This principle is known as the __________.

The principle is called the equimarginal principle. It says a consumer should keep spending on each good until the last dollar spent on every good yields the same marginal utility per dollar. If one good gives more marginal utility per dollar, the consumer should shift money toward that good until equality is reached. For example, if pizza gives 10 MU per dollar and soda gives 5 MU per dollar, the consumer should buy more pizza until the marginal utility per dollar of pizza equals that of soda, maximizing overall utility.