Assume that you manage a risky portfolio with an expected rate of return of 15% and a standard deviation of 37%. The T-bill rate is 5% A client prefes to invest in your portfolio a proportion (y that maximizes the expected returt on the overall portfolio subject to the constraint that the overall portiolio's standard deviation will not exceed 25% Required: a. What is the investment proportion. y? (Do not round intermediate calculations. Round your answer to 2 decimal places.) b. What is the expected rate of return on the overall portfolio? (Do not round intermediate calculations. Round your answer to 2 decimal places.)