8. A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
A. 16 days
B. 18 days
C. 15 days
D. 12 days
8. A, B and C can do a piece of work in 20, 30 and 60 days respectively. In how many days can A do the work if he is assisted by B and C on every third day?
A. 16 days
B. 18 days
C. 15 days
D. 12 days