A and B can together do a piece of work it in 6 days and A alone can do it in 9 days. The number of days B will take to do it alone is ?

A. 18 days

B. 24 days

C. 9 days

D. 12 days

Answer: Option A

Solution(By Examveda Team)

L.C.M. of Total Work = 36
One day work of A + B = $$\frac{{36}}{{6}}$$ = 6 unit/day
One day work of A = $$\frac{{36}}{{9}}$$ = 4 unit/day
$$\eqalign{ & {\text{B's efficiency}} \cr & = 6 - 4 \cr & = 2 \cr & {\text{Time taken by B}} \cr & = \frac{{36}}{2} \cr & = 18{\text{ days}} \cr} $$