A and B working separately can complete a piece of work 60 days and 70 days, respectively. If they work for a day alternately, B beginning, in how many days will the work be completed?
1
\(64\frac{2}{3}\) days
2
\(63\frac{2}{3}\) days
3
\(66\frac{2}{3}\) days
4
\(65\frac{2}{3}\) days