Final answer:
When Emilio's income doubles, his marginal utility per dollar for normal goods will be smaller than before his income increase.
Step-by-step explanation:
When Emilio's income doubles, he adjusts his consumption accordingly. If the goods that Emilio buys are normal goods, then his marginal utility per dollar will be smaller than before his income increase. This is because the increase in income allows him to buy more of the goods he wants, causing the additional units of the goods to provide him with less overall satisfaction compared to the initial units.