Let MUA = z = 10 − x and MUB = z = 21 − 2y, where z is marginal utility per dollar measured in utils, x is the amount spent on product A, and y is the amount spent on product B. Assume that the...

Let MUA = z = 10 − x and MUB = z = 21 − 2y, where z is marginal utility per dollar measured in utils, x is the amount spent on product A, and y is the amount spent on product B. Assume that the consumer has $10 to spend on A and B—that is, x + y = 10. How is the $10 best allocated between A and B? How much utility will the marginal dollar yield?