Bundle L contains 10 units of good X and 20 units of good Y. Bundle M contains 8 units of good X and 21 units of good Y. The consumer is indifferent between bundle L and bundle M. Assume that the consumer’s preferences satisfy the four properties of indifference curves. Which of the following correctly expresses the marginal rate of substitution of good X for good Y between these two points?

a. The consumer will give up 1 unit of good X to gain 2 units of good Y.
b. The consumer will give up 2 units of good X to gain 1 unit of good Y.
c. The price of good X is twice as large as the price of good Y.
d. The price of good X is half as large as the price of good Y.
Consider the indifference curve map for nickels and quarters. Assume nickels are on the horizontal axis and quarters are on the vertical axis. The indifference curves for nickels and quarters are

a. straight lines with slope of -1/5.
b. straight lines with a slope of -1.
c. straight lines with a slope of -5.
d. L shaped.