So the first part of the question is 1A. "You have $50,000 you want to invest in a combination of the Dow Jones and US Treasuries. Assume the Dow Jones is the market portfolio (m) and has an expected return of 9% and standard deviation of 15%. Assume US Treasuries are the risk free asset (f) and have a risk-free rate of 5%. Given your willingness to accept a standard deviation of 11%, what is the expected return on your portfolio, assuming you want to maximize your expected return?"

I calculated this to be 7.9%. The second and third part confuse me:

1B. "A hedge fund has a beta of 0.7 and standard deviation of 9%. What is the expected return if you were to invest in this hedge fund? What is the covariance between the returns on this fund and the Dow Jones?"

C. "In a portfolio consisting of 85% Dow Jones and 15% this hedge fund, what is the expected return and standard deviation? What is the sharpe ratio and is it higher, lower, or equal to the Sharpe ratio of the Dow Jones?"

Assuming my answer to the first part is correct, how would I go about answering the second and third part?