help please :)

Find the sample variance of these returns. The risk free rate is 0.027. If there is a risky asset with an expected return of 0.3, what would be the expected return on a portfolio with a weight of 0.8 on the risky asset, and a weight of 1-0.8 on the risk free asset? If there is a risky asset with a standard deviation of 0.27, what would be the standard deviation of a portfolio with a weight of 0.8 on the risky asset, and a weight of 10.8 on the risk free asset