13. A well-diversified Portfolio, X, has an arithmetic average return of 8%. The average risk-free rate is 3%. The beta (sensitivity to the market excess return) of X is 2. The standard deviation of the market portfolio is 30%. a) Calculate the Sharpe Ratio of X. (Hint: X is a well-diversified portfolio.) b) Suppose the Capital Asset Pricing Model (CAPM) holds. Calculate the Sharpe Ratio of the market portfolio using the above information