Raju, Shobh and Mohan can do a work in 15 days, 20 days and 25 days respectively. In how many days,will the work be finished, if they do it on alternate days, Starting from Raju?
1
\(15\frac{9}{{10}}\) days
2
\(18\frac{7}{{10}}\) days
3
\(21\frac{7}{{10}}\) days
4
\(18\frac{9}{{10}}\) days