Maria has a budget of $10 to spend on apples and oranges. Apples cost $2 each and oranges cost $1 each. If Maria decides to buy 3 apples, how should she allocate her remaining budget to maximize her total utility, considering the marginal utility she receives from each fruit? Assume she derives more satisfaction from each additional orange than from an additional apple after the third apple.

Maria starts with a budget of $10 and spends $6 on 3 apples, since each apple costs $2. This leaves her with $4 to spend on oranges. Since she gets more satisfaction from each additional orange than from another apple after the third apple, she should use her remaining budget to buy oranges. At $1 each, she can buy 4 oranges, which gives her more total utility than if she spent the money on more apples. By choosing to buy oranges, Maria maximizes her satisfaction with her budget.