A can do a piece of work in 20 days and B in 15 days. With help of C, they finish the work in 5 days. C can alone do the work in
1
5 days
2
6 days
3
10 days
4
12 days
A can do a piece of work in 20 days and B in 15 days. With help of C, they finish the work in 5 days. C can alone do the work in