A job can be completed by $12$ men in $12$ days. If $6$ men leave after working for $6$ days, how many extra days are needed to finish the job?

Question

A job can be completed by $12$ men in $12$ days. If $6$ men leave after working for $6$ days, how many extra days are needed to finish the job?

Option A

3

Option B — Correct answer

6

Correct choice.

Option C

9

Option D

12

Explanation

Total work $=12\times12=144$ man-days. Work done in 6 days by 12 men $=72$. Remaining work $=72$. With 6 men left, time needed $=72\div6=12$ days. Since 6 days have already passed, the extra days needed are $6$.

Chapter Mock 7: Time and Work, Pipe and Cistern