Thirty six men take 30 days to complete a job working 8 hours a day. How many…
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Thirty six men take 30 days to complete a job working 8 hours a day. How many hours a day should 40 men work to complete the job in 24 days ?
- A.
7 hrs
- B.
8 hrs
- C.
6 hrs
- D.
9 hrs
Attempted by 55 students.
Show answer & explanation
Correct answer: D
Answer: 9 hrs
Reasoning:
Compute the total work in man-hours from the original data.
Total work = number of men × days × hours per day = 36 × 30 × 8 = 8640 man-hours.
Let h be the hours per day needed for 40 men in 24 days.
Required work produced = 40 × 24 × h, and this must equal 8640.
Solve for h: h = 8640 ÷ (40 × 24) = 8640 ÷ 960 = 9.
Thus, 40 men must work 9 hours a day for 24 days to complete the job.