help please

i need it to be in excel work.

Assume that you manage a risky portfolio with an expected rate of return of 15% and a standard deviation of 29%. The T-bill rate is 5%. Your client decides to invest in your risky portfolio a proportion (y) of his total investment budget with the remainder in a T-bill money market fund so that his overall portfolio will have an expected rate of return of 12 Required: a. What is the proportion y? (Round your answer to 1 decimal place.) Proportion y %6 b. What is the standard deviation of the rate of return on your client's portfolio? (Round your intermediate calculations and final answer to 1 decimal place.) Standard deviation % per year