Security A has an expected return of 10 percent and a standard deviation of 43 percent per year. Security B has an expected return of 15 percent and a standard deviation of 62 percent per year.

a. What is the expected return on a portfolio composed of 30 percent of Security A and 70 percent of Security B?

b. If the correlation between the returns of Security A and Security B is 0.25, what is the standard deviation of the portfolio described in part (a)?