Samrat alone can complete a work in 10 days and Virat alone can complete the same work in 40 days. If they are working on alternate days with Samrat starting the work, then in how many days will the total work be completed?

16 days

Samrat = 10 days,

Virat = 40 days,

⇒ They both work on alternate days, starting with Samrat,

 1st day = 4 units

 2nd day = 1 unit 

Every 2 days = 5 units of work,

So, in 16 days, 40 units of work will be completed,

Therefore, work will be completed in 16 days.