(1)投资人要求的必要报酬率=6%+2×(10%-6%)=14%Vs=2×(P/A,14%,2)+[2×(1-2%)/(14%+2%)]×(P/F,14%,2)=2×1.6467+12.25×0.7695=12.72(元)(2)净现值=2×(P/A,Rs,2)+13×(P/F,Rs,2)12设利率为20%,净现值=2×1.5278+13×0.6944-12=0.0828(元)设利率为24%,净现值=2×1.4568+13×0.6504-12=-0.6312(元)(Rs-20%)÷(24%-20%)=(0-0.0828)÷(-0.6312-0.0828)Rs=20.46%