先把资本成本率作为贴现率，计算出NPV即NPV＝－80000+12800*0.9346+12500*0.8734+12415*0.8163+12325*0.7629+12100*0.7130+12050*0.6663+11900*0.6227+11250*0.5820+10400*0.5439+（9300+800）*0.5083如此把结算计算出即可
