问题1:

问题2:
A方案综合得分: 9×0.333+8×0. 200+10×0. 267+7×0. 067+8×0. 133=8. 80 (分)
B方案综合得分: 8×0. 333+10×0.200+9×0.267+9×0. 067+10×0. 133=9.00 (分)
C方案综合得分: 10×0. 333+9×0.200+8×0.267+9×0.067+8×0.133 =8.93 (分)
所以,B方案为最优方案。
问题3:.
(1)各方案的工程总造价:
A方案: 65×8000=520000 (元) =52(万元)
B方案: 80×8000=640000 (元)=64(万元)
C方案: 115×8000=920000 (元) =92 (万元)
(2)各方案全寿命周期年度费用:
A方案:
1.4+52 (A/P, 6%,40)+ (32+1) [(P/F, 6%,5) +(P/F,6%,10) + (P/F,6%,15) + (P/F,6%,20) +(P/F, 6%,25)+(P/F, 6%,30)+ (P/F, 6%,35)] ×(A/P, 6%,40)
=1.4+52×0. 0665+33×(0. 7474+0. 5584+0. 4173+0. 3118+0. 2330+0. 1741+0.1301)×0. 0665
=1. 4+3. 458+5. 644
=10.52 (万元)
B方案:
1. 85+64 (A/P, 6%,40) + (44+1)[(P/F,6%,10) + (P/F,6%,20) + (P/F,6%,30)] (A/P,6%,40)
=1.85+64×0.0665+45×(0. 5584+0.3118+0.1741)×0. 0665
=1.85+4.256+3.125
=9.23 (万元)
C.方案:
2.70+92 (A/P,6%,40)+(60+1) [(P/F, 6%,15) + (P/F, 6%,30)] (A/P, 6%,40)
=2.70+92×0.0665+61× (0. 4173+0. 1741)×0.0665
=2.70+6.118+2. 399
=11.22(万元)
所以,B方案为最经济方案。