The securities of companies Jack and Jones have the following expected returns and standard deviations: Jack Jones Expected return (%) 15 35 Standard deviation (%) 20 40 If the correlation coefficient between the two securities is ?0.25, calculate the expected return and standard deviation for the following portfolios: (a) 100 per cent Jack; (b) 75 per cent Jack and 25 per cent Jones; (c) 50 per cent Jack and 50 per cent Jones; (d) 25 per cent Jack and 75 per cent Jones; (e) 100 per cent Jones.