Difficulty: Medium
Correct Answer: 7 days
Explanation:
Introduction / Context:
Here, workforce changes partway through the project. The correct approach is to use man-days (men * days) to measure total work and calculate what remains after the first phase, adjusting for the new team size afterwards.
Given Data / Assumptions:
Concept / Approach:
Remaining work (in man-days) divided by the new daily capacity (men per day) gives remaining days.
Step-by-Step Solution:
Total work = 168 man-days.Done in first phase = 56 man-days.Remaining = 168 − 56 = 112 man-days.With 16 men: days needed = 112 / 16 = 7 days.
Verification / Alternative check:
Performing the calculation in fractional jobs gives the same answer; the man-day approach is clean and direct here.
Why Other Options Are Wrong:
5, 6, 8, or 9 days are not consistent with 112 man-days divided by 16 men.
Common Pitfalls:
Not converting to man-days first or assuming proportionality without accounting for the first phase’s contribution.
Final Answer:
7 days
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