dont understand question 3 & 4

Jocko was just told that the expected return for Echo stock was 20%, based on the CAPM. Assuming that the market return and the risk-free rate are 12% and 4%, respectively, what is the beta for Echo? a. 1.0. e c XYZ common stock has a beta of 0.50, while ABC common stock has a beta of 2.0. The expected return on the market is 12% and the risk-free rate is 1%. Based on the capital asset pricing model (CAPM) and making use of the information, the required return on the XYZ common stock should be and the required return on ABC common stock should be a. 4%: 16%. b. 6%: 24%. c. 8%: 20%. d. 10%: 28%