Suppose you purchased $1,000 of Stock A with your own money. You then borrowed $500 and used this money to buy Stock B. This means that the portfolio weights are as follows: wA = 1000/1000 = 1.00; wB = 500/1000 = 0.50; wC = -500/1000 = -0.50. The correlation coefficient between A and B is 0.70; interest rate on the risk-free asset (Security C) is 5%; variance of Stock A is 0.25; variance of Stock B is 0.49; expected return on Stock A is 10% and Stock B is 16%. Risk and Return. Calculate the variance of a portfolio of the three securities.