30 men take 20 days to complete a job working 9 hours a day. how many hour a day should 40 men work to complete the job? Choose the correct answer: A) 6.79 B) 6.75 C) 6.71 D) 6.74 E) 6.712
Explanation:   Let the capacity of man in hour is 1 unit. Then total work = 30 × 20 × 9   40 men in 20 days working t hours a day can complete = 40 × 20 × t   ⇒ 40 × 20 × t = 30 × 20 × 9   ⇒ t = 6.75 hours.   Answer: 6.75
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30 men take 20 days to complete a job working 9 hours a day. how many hour a day should 40 men work to complete the job?