Two tames need 18 days to complete an engineering taks.Tame A have worked 3 days.Tame B have worked

题目

Two tames need 18 days to complete an engineering taks.Tame A have worked 3 days.Tame B have worked 4days.They have finished one fifth of the task.If team A complete the task by them selves they need ( )days.

答案

答案：36 (days).
假设：总任务量为1,team A的工作速度为a/天,team B的工作速度为b/天,则据题意就有：
18×(a+b)=1
3a+4b=1/5
求解上述方程得到：a=1/45；b=1/30.
当team A独自完成剩余4/5任务时,据题意就有：4/5÷1/45=36 (days).