Solutions for Chapter 7: Questions and Problems
3a. Q: 4.8%/10.5% = 0.4571
3b. The CML slope, [E(RMKT ) – RFR ]/ σMKT , is the ratio of risk premium per unit of risk.
Portfolio R has the highest ratio, 0.5000, of these five portfolios so it is most likely the
market portfolio. Thus, the slope of the CML is 0.5; its intercept is 3%, the risk-free
rate.
3d. Using the CML equation, we set the expected portfolio return equal to 7% and solve for
the standard deviation:
E(Rportfolio ) = 7% = 3% + (0.50) σportfolio ➔ 4% = (0.50) σportfolio ➔ σ = 4%/0.50 = 8%.
Thus, 8% is the standard deviation consistent with an expected return of 7%.
3e. To find the portfolio weights with result in a risk of 18.2%, recall that the covariance
between the risk-free asset and the market portfolio is zero. Thus, the portfolio standard
deviation calculation simplifies to: σportfolio = wMKT (σMKT ) and the weight of the risk-
free asset is 1 – wMKT .