=+b. The price of a pair of Nikes falls to $50 each, but the price of sunglasses remains at $50 per pair. Which bundles lie on Cal’s budget line? Draw a diagram like Figure 10-4 in which both the marginal utility per dollar spent on Nikes and the marginal utility per dollar spent on sunglasses are illustrated. Use this diagram and the utility-maximizing principle of marginal analysis to decide how Cal should allocate his money. That is,