I need the answers with explain how to answer this questions

You invest $100 in a risky asset with an expected rate of return of 0.15 and a standard deviation of 0.15 and a Tbill with a rate of return of 0.04 . If you want to form a portfolio with an expected rate of return of 0.09 , what percentage of your money must you invest in risky portfolio? If you want to form a portfolio with an expected rate of return of 0.09 , what percentage of your money must you invest in the risk free asset? What is the standard deviation of the rate of return of the complete portfolio? What is the reward-to volatility ratio of the complete portfolio? What is the reward-to volatility ratio of the complete portfolio? Did you construct the optimal portfolio? If yes write down1 and if not write down 2