Suppose we have two risky assets, Stock | and Stock], and a riskfree asset. Stock I has an expected retum of 25% and a beta of 1.5. Stock] has an expected retum of 2D% and a beta of {1.8. The riskfree asset's return is 5%. {13 marks} a. Calculate the expected retums and betas on portfolios with x% invested in Stock | and the rest invested in the riskfree asset, where xiii: = {3%, 512%, 1D%. and 150%. {2 marks] b. Using the four portfolio betas calculated in part {a}, reverse engineer [i.e., derive mathematically} the portfolio weights for a portfolio consisting of only Stock] and the riskfree asset. {4 marks] Hint: For example, if we wished to obtain a portfolio beta of [1.5, then the weights on Stock] and the riskfree asset must be 62.5% and 32.5%, respectively, and the expected return for this portfolio must be 14.325916. c. Calculate the rewardtorisk ratios for Stock | and Stock]. {2 marks]