Vikas and Mohan working together can complete a work in 6 days. If Vikas alone completes the same work in 10 days, in how many days Mohan alone can complete the same work?

Question: Vikas and Mohan working together can complete a work in 6 days. If Vikas alone completes the same work in 10 days, in how many days Mohan alone can complete the same work?

Solution:
Vikas and Mohan together can complete the task in 6 days.
So, in one day, they will complete 1/6 part of the task.

Therefore, (Vikas + Mohan)'s one day work will be = 1/6
Similarly, Vikas's one day work = 1/10
Therefore, Mohan's one day work = 1/6 - 1/10 = (5 - 3)/30 = 2/30 = 1/15

In one day Mohan completes the 1/15 part of the work so he will complete the entire work in 15 days.