Question
A takes 6 days less than the time taken by B to finish a piece of work. If both A and B together can finish it in 4 days, find the time taken by B to finish the work.
Solution
Suppose B alone takes x days to finish the work. Then, A alone can finish it in (x - 6) days.
Now, (A’s one day’s work) + (B’s one day’s work)
and 
∴ 
But, x cannot be less than 6.
So, x = 12.
Hence, B alone can finish the work in 12 days.
