Why might two people diagnosed with exactly the same type of pain-inducing physical problem opt to place different levels of daily stress on their bodies?

Sue's monthly budget for bottled water and soft drinks is $\$23$. The price of bottled water is $\$1$ per bottle, and the price of soft drinks is $\$2$ per bottle. Calculate the slope of Sue's budget constraint. Given this information and the information provided in Problem $F-3$, find the combination of goods that satisfies Sue's utility-maximization problem in light of her budget constraint.

Explain why it must be true, even for someone trying to lose weight, that the last bite of food consumed must have positive marginal utility at a consumer optimum?

Using the indifference curve diagram you constructed in Problem F-4, add in Sue's budget constraint using the information in Problem F-5. Illustrate the utility-maximizing combination of bottled water and soft drinks.

The table below represents Sue's preferences for bottled water and soft drinks, the combination of which yields the same level of utility.

Calculate Sue's marginal rate of substitution of soft drinks for bottled water at each rate of consumption of water (or soft drinks). Relate the marginal rate of substitution to marginal utility.

Explain why an optimal choice of how much to consume entails equalizing the marginal utility per dollar spent across all items.