平均寿命表e[img=~/QImg/2013-10-14-11-12-39/image054.jpg]的计算公式为

A、[img=~/QImg/2013-10-14-11-12-39/image055.jpg]
B、[img=~/QImg/2013-10-14-11-12-39/image056.jpg]
C、[img=~/QImg/2013-10-14-11-12-39/image057.jpg]
D、[img=~/QImg/2013-10-14-11-12-39/image058.jpg]
E、以上均不对