
答案
(1)净现值法
NPVA=-140+24X(P/A,15%,10)+125 X(P/F,15%,10) =11.35 万元 NPV3=-190+31X(P/A,15%,10)+155 X(P/F,15%,10)= 3.90 万元 NPVc=-220+41X(P/A,15%,10)+175 X(P/F,15%,10)= 29.03万元 NPVc最大,故C方案最优。
(2)差额净现值法
NPVA-0=-140+24X(P/A, 15%,10)+125 X (P/F,15%,10) =11.35 万元 NPV3-A=-50+7X(P/A,15%,10)+30X(P/F,15%,10)=-7.45 万元 NPVc-A=-80+17X (P/A,15%,10)+50X(P/F,15%,10)= 17.68 万元故C方案最优。