A job is planned for 36 men to finish in 48 days. After 24 days, only 2/5 of the work is completed. How many additional men must be employed so that the work is still finished within the original 48-day schedule?

Introduction / Context:
When progress lags behind schedule, we can increase the workforce to meet the deadline. We compare required man-days with what remains to determine the additional men needed.

Given Data / Assumptions:

• Planned crew = 36 men for 48 days.
• After 24 days, only 2/5 of the work is done.
• Goal: finish by day 48 (24 more days).

Concept / Approach:
Total work can be expressed in man-days. Using progress data, infer the project’s true size, then compute remaining man-days and divide by remaining days to get the required headcount.

Step-by-Step Solution:

Verification / Alternative check:
54 men * 24 days = 1296 man-days remaining; matches need exactly.

Why Other Options Are Wrong:

• 16, 14: Under-hire; would miss deadline.
• 20, 22: Over-hire; more than necessary given exact calculation.

Common Pitfalls:
Using planned total (36*48) as actual work without adjusting for the slower-than-expected progress; forgetting to subtract completed man-days before computing requirements.

Final Answer:
18