4. A certain portfolio II consists only of shares of stocks X and Y. The following information about the annual returns of the stocks is known: The expected returns of X and of Y are 5% and 10% respectively, The volatilities of the returns of X and Y are 10% and 20% respectively, The correlation coefficient of the returns is 0.3. (a) Calculate the weight of each stock if the expected return of the portfolio is 8%. (b) Calculate the volatility (risk) of the portfolio return