A and B can together complete a piece of work in 6 days. If A alone can complete the same work in 12 days, in how many days can B alone complete that work?
Answer & explanation
Correct answer: option 2
The correct answer is Option (2) → 12 days
A person who finishes a job in \(n\) days does \(\frac{1}{n}\) of it in one day, and when two work together their one-day work is added. B’s one-day work is the joint figure minus A’s.
A and B together: \(\frac{1}{6}\) of the work a day
A alone: \(\frac{1}{12}\) of the work a day
B alone: \(\displaystyle \frac{1}{6}-\frac{1}{12}=\frac{2-1}{12}=\frac{1}{12}\), so B takes 12 days