A and B alone can do a piece of wok in 8 and 18 days respectively In how many days the work will be ...........

Explanation:

Answer & Explanation
C) 10 7/9 days
Explanation: 
A = 8 days, B = 18 days
Total work = LCM(8,18) = 72
So efficiency of A = 72/8 = 9, efficiency of B = 72/18 = 4
2 days work of (A+B) = 9+4 = 13
2*5(10) days work of (A+B) = 9+4 = 13*5 = 65
So remaining work = 72-65 = 7
Now A’s turn on 6th day, he will do remaining work(7) in 7/9 day
So total 10 7/9 days