Is Part A as simple as accepting the individual projects with an expected return greater than 15%?

For Part B, would you use the Expected Stock Return formula and accept projects greater than 15%? For example, project #1, r = 8 + 0.5(7) = 11.5%, so do not accept this project? For project #2, 8+0.8(7) = 13.6, don't accept?