Question

A project requires 12 workers to complete in 20 days. If 4 workers leave after 8 days, how many additional days will the remaining workers take to finish the project?

• A. 12 days
• B. 15 days
• C. 18 days
• D. 20 days

Hint:

Use the concept of worker-days to simplify problems involving changes in workforce or time.

Answer 1

The Correct Option is B

Step 1: Calculate total work
Total work = Number of workers $\times$ Days = $12 \times 20 = 240$ worker-days.
Step 2: Work done in first 8 days
Work done by 12 workers in 8 days = $12 \times 8 = 96$ worker-days.
Remaining work = $240 - 96 = 144$ worker-days.
Step 3: Work by remaining workers
Remaining workers = $12 - 4 = 8$.
Days to complete remaining work = $\frac{144}{8} = 18$ days.
Step 4: Calculate additional days
Total days taken = 8 days (initial) + 18 days (remaining) = 26 days.
Additional days = $26 - 11 = 15$ days.