A completes \(\frac{7}{10}\) part of work within 15days. Thereafter with the help of B, he completes the rest of the work within 4 days. B alone will be able to do it in how many days.
1
\(21\frac{3}{7}\) days
2
\(35\frac{5}{17}\) days
3
\(28\frac{5}{12}\) days
4
\(30\frac{7}{17}\) days