A方案PI=100*(P/A,10%,6)/200=2.18
B方案PI=[100/(1%2B10%)^2%2B120/(1%2B10%)^3%2B140/(1%2B10%)^4%2B110/(1%2B10%)^5]/200=1.68
C方案PI=[80/(1%2B10%)^2%2B100/(1%2B10%)^3%2B110/(1%2B10%)^4%2B130/(1%2B10%)^5%2B140/(1%2B10%)^6]/[100%2B100/(1%2B10%)]=1.97
三个方案PI均大于1,都可行,优选A,然后c,然后b