Revised crew after day 3: how long to finish? Twelve men can complete a work in 8 days. After 3 days, three more men join the team. In how many days will they complete the remaining work?

Introduction / Context:
This scenario uses man-days to track total effort. Once some work is done by the original team, add the new hires and compute how many days are necessary to deliver the remainder.

Given Data / Assumptions:

• 12 men finish in 8 days ⇒ total work = 96 man-days.
• First 3 days: 12 men work ⇒ 36 man-days completed.
• Then 3 more men join (total 15 men).

Concept / Approach:
Remaining work = 96 − 36 = 60 man-days. With 15 men, time = remaining / 15.

Step-by-Step Solution:

Verification / Alternative check:
Overall duration = 3 + 4 = 7 days, which is less than 8 because of extra manpower.

Why Other Options Are Wrong:
2, 5, 6 do not correspond to 60/15.

Common Pitfalls:
Forgetting to compute the first 3 days of progress before adding the newcomers.

Final Answer:
4