As a portfolio manager you are provided with the below information relating to the risk and return of 2 stocks namely Stock X and Y: 

• The expected returns of X and Y are E[RX] = 10% and E[RY] = 15%. 

• The volatilities of the returns are σX =18% and σY = 20%. 

• The correlation coefficient of the returns for these two stocks is 0.25. 

• The expected return for a portfolio, consisting of stocks X and Y, is 12%.

(a) You are required to calculate the volatility of the portfolio return.