Sally consumes two goods. X and Y. Her utility function is given as: U = 500 YOY 08 The current market price for X is $15 and the market price for Y is $50. Sally's current income is $500,000. a. Determine the X, Y combination that maximizes Sally's utility. What is Sally's total utility? b. If the price of X rises to $25, determine the combination of X and Y that maximizes Sally's utility. What is her total utility? c. Based on your answer to parts a and b, write out the linear demand function of good X for Sally. d. Using the demand function derived in part c, sketch Sally's demand curve for good X