To do a certain work, the ration of efficiency of A to that of B is 3 ∶ 7 Working together, they can complete the work in \(10\frac{1}{2}\) days. They work together for 8 days. 60% of the remaining work will be completed by A alone in∶
1
\(6\frac{1}{2}days\)
2
4 days
3
\(5\frac{1}{2}days\)
4
5 days