Final answer:
The optimal choice for a consumer occurs when the marginal utility per dollar spent on all goods is equal, which reflects the point of consumer equilibrium. This is where a consumer has allocated their budget across goods in a way that maximizes their total utility.
Step-by-step explanation:
The consumer's optimal choice for maximizing utility occurs when the marginal utility per dollar spent on good X is equal to the marginal utility per dollar spent on good Y. This concept is an essential principle of consumer equilibrium in economic theory, reflecting a situation where a consumer has balanced their expenditures on different goods to achieve the highest possible satisfaction given their budget constraints.
When consumers make buying decisions, they implicitly compare the additional satisfaction (utility) they get from purchasing a little bit more of one good with its cost—and they do the same for other goods. When the ratio of marginal utility to price for all goods is equal, consumers have no incentive to reallocate their budget; they're getting equal value from the last dollar spent on each good.
For example, if José finds that the marginal utility per dollar spent on T-shirts is 1.6, and on movies it is 2.3, the utility maximizing strategy would suggest that he should initially purchase the movie, as it offers a higher marginal utility per dollar. Subsequent purchases would depend on the declining marginal utility of each good until the point where the utility gained per dollar is equal for both goods, indicating he has reached his equilibrium.