Your company is considering two mutually exclusive projects, X1 and X2: also considered are 2 projects, Y and Z, independant of the X projects and each other. The project costs and cash flows are shown below: Projects X1 and X2 are equally risky, and the firm's required rate of return is 12 percent. Which projects should be accepted and which should be rejected? Base your decision on any method, but justify the use of the method you have chosen