a. You own a portfolio that is 50 percent invested in Stock X, 30 percent in Stock Y, and 20 percent in Stock Z. The returns on these three stocks are 10 percent, 18 percent and 13 percent, respectively. What is the return on the portfolio?

b. You have $10,000 to invest in a stock portfolio. Your choices are Stock X with a return of 15 percent and Stock Y with a return of 10 percent. If your goal is to create a portfolio with a return of 13.5 percent, how much money will you invest in Stock X? In Stock Y?