7. Assume that you manage a risky portfolio with an expected rate of return of 23% and a standard deviation of 43%. The T-bill rate is 3%. A client prefers to invest in your portfolio a proportion (y) that maximizes the expected return on the overall portfolio subject to the constraint that the overall portfolio's standard deviation will not exceed 35%. a. What is the investment proportion, y ? b. What is the expected rate of return on the overall portfolio