A can do a work in 4 days, B can do same work in 8 days, then the time taken by A and B to do the same work together is:
Answer & explanation
Correct answer: option 1
The correct answer is Option (1) → 8/3 days
In time-and-work questions, a person who finishes a job in \(n\) days does \(\frac{1}{n}\) of it in one day, and when two people work together their one-day work is added.
A’s one-day work \(=\frac{1}{4}\); B’s one-day work \(=\frac{1}{8}\)
Together in one day: \(\displaystyle \frac{1}{4}+\frac{1}{8}=\frac{3}{8}\) of the work
Time together \(\displaystyle =1\div\frac{3}{8}=\frac{8}{3}\) days (2 days 16 hours)
Tip: \(\frac{3}{8}\) (Option 2) is the work done together in one day, not the time; the time is its reciprocal.