A and B working separately can do a piece of work in 9 and 15 days respectively. If they work for a day alternately, with A beginning, then the work will be complete in :
A and B working separately can do a piece of work in 9 and 15 days respectively. If they work for a day alternately, with A beginning, then the work will be complete in :
[A]9 days
[B]10 days
[C]11 days
[D]12 days
11 days
A’s 1 day’s work
B’s 1 day’s work
Work done in first 2 days = A’s 1 day’s work + B’s 1 day’s work
∴ Work done in first 10 days
Remaining work
Now it is turn of ‘A’ for the eleventh day.
∴ Time taken by ‘A’ in doing 
Hence option [C] is correct answer.
