年折旧额 =(320000–20000)/10 =30000元
NCF0=-320000元
NCF1-9=(250000–178000–30000)×(1–35%)+30000=57300元
NCF10 = 57300+20000 =77300元
当i=12%时:NPV=57300×(P/A,12%,9)+77300×(P/F,12%,10)-320000
= 57300×5.3282+77300×0.3220-320000
= 10196.46元
当i=14%时: NPV =57300×(P/A,14%,9)+77300×(P/F,14%,10)-320000
=57300×4.9164+77300×0.2697–320000
=-17442.47元
则:IRR = 12%+[10196.46/( 10196.46 +17442.47)]×(14%-12%)
= 12.73%
因为NPV=10196.46 〉0,IRR=12.73% 〉资金成本率12% , 所以该方案可行。