Q4[20 points] Ursula views one cup of frozen yogurt to be a perfect substitute for three pieces of chocolate chip brownies. A cup of frozen yogurt sells for $6, and a piece of brownies is $3, and Ursula has a monthly budget of $180 to buy frozen yogurt and brownies.

a) What bundle should Ursula buy to maximize her utility? Show how to determine this bundle on a diagram using indifference curves and a budget line ((with frozen yogurt -Y- on the vertical axis).

b) If the price of a cup of frozen yogurt increases to $9, how would Ursula's behavior change? Show the utility-maximizing bundles on diagrams with budget line and indifference curves (with frozen yogurt -Y- on the vertical axis).