24. Suppose initially that the price of X is $5, the price of Y is $10, and the consumer's income is $100. If Y is measured on the vertical axis, X is measured on the horizontal axis, and the price of Y increases to $20: a. the entire budget line will shift inward toward the origin, with its slope changing from -1/2 to -1/4. b. the budget line will pivot inward toward the origin along the X axis, with its slope changing from -1/2 to -1/4. c. the budget line will pivot inward toward the origin along the Y axis, with the slope changing from -1/2 to -1/4. d. the budget line will pivot inward toward the origin along the Y axis, with the slope changing from -1/4 to -1/2. 25. Compared to the marginal rate of substitution at the original optimal consumption point, the marginal rate of substitution at the new optimal consumption point is lower if: a. the consumer's income increased. b. the price fell. c. the price rose. d. the consumer's income decreased. 26. Which of the following must be true for a Giffen good? a. The good must be inferior and the substitution effect must be larger than the income effect. b. The good must be inferior and the income effect must be larger than the substitution effect. c. Both the income and the substitution effect of a price rise will be positive. d. Both the income and the substitution effect of a price rise will be negative 27. X is on the horizontal axis and Y on the vertical axis. If you are consuming at an optimal point on an indifference curve such that the slope at that point was -4, which of the following best describes your consumption bundle? a. Your marginal utility of X is 20 and for Y it is 20. b. Your marginal utility of X is 5 and for Y it is 20. c. Your marginal utility of X is 20 and for Y it is 5. d. Your marginal utility of X is 4 and for Y it is 4. 28. In case of a normal good, the income and substitution effects: a. always work together and both tend to make the demand curve downward sloping. b. always work in the opposite direction to one another. c. just offset each other. d. work together, both tending to make the demand curve upward sloping