A can do a work in 20 days and B can do it in 8 days. In how many days A and B can do the work?  Select the correct option:
A) 5 5/7 days
B) 10 days
C) 6 days
D) 8 days
E) 7 days
Explanation:   5 5/7 days's 1day's work = 1/20   B's 1day's work = 1/8   They work together = 1/20 + 1/8 = 7/40 = 40/7 = 5 5/7days   5 5/7 daysnswer: Option 5 5/7 days
<result>A</result>
A can do a work in 20 days and B can do it in 8 days. In how many days A and B can do the work?