PLEASE SHOW WORK HOW TO GET THE ANSWER

A.What is the mean return for Stock A with the following annual holding period returns? What is Stock As standard deviation of returns?10% ; 5.1%

Year	Return
1	15%
2	3%
3	12%

B.American Express stock has a standard deviation of 31.78%, while General Motors stock has a standard deviation of 38.60%. The correlation coefficient between the two stocks is 0.2445. What is the standard deviation of a portfolio consisting of 40% AMEX and 60 percent GM?29.02%