ABC has an expected return of 18% and a standard deviation of 20%. XYZ has an expected return of 32% and a standard deviation of 40%. What is the variance of a portfolio that invests 25% in ABC and the remainder in XYZ, if the correlation between the two securities is 70%?（ ）
The variance of the portfolio is (0.25.×0.20)2+ (0.75×0.40)2+ 2×0.25×0.75×0.20×0.40× 0.70= 0.1135. Then the standard deviation is 0.3369.