A can do a piece of work in 20 days and B can do the same piece of work in 30 days. A and B started the work together in the first 10 days A worked with half of his efficiency and so does B. Now in how many days does the remaining work get completed when both of them work with their full efficiency?
1
7 days
2
5 days
3
8 days
4
3 days
5
None of these