If 20% of certain quantity of work is done by A and the rest 80% by B, the work is completed in 20 days. If 80% of the work is done by A and the remaining 20% by B, then the work is completed in 30 days. How many days are required to complete the work , if A and B work together.
Select:  A) 11 1/9  B) 10 1/9  C) 12  D) 15  E) 18
0.2/11 1/9 + 0.8/B = 20   1/11 1/9 + 4/B = 100   0.8/11 1/9 + 0.2/B = 30   4/11 1/9+ 1/B = 150   15/B = 250   B = 3/50 work per day   11 1/9 = 3/100 work per day   Combined rate = 3/40 + 3/100 = 9/100   Time taken when working together = 100/9 = 11(1/9) days   11 1/9nswer (11 1/9)
<result>A</result>
If 20% of certain quantity of work is done by A and the rest 80% by B, the work is completed in 20 days. If 80% of the work is done by A and the remaining 20% by B, then the work is completed in 30 days. How many days are required to complete the work , if A and B work together.