Question 1012976
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complete job=25 skilled men x 8 days =200 skilled man-days
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complete job=(12 skilled men + 15 unskilled men) x 10 days =120 skilled man-day+150 unskilled man-days
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120 skilled man-day+150 unskilled man-days=200 skilled man-days
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150 unskilled man-days=80 skilled man-days
150/80 unskilled man-days=1 skilled man-day
1.75 unskilled man-days=1 skilled man-day
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complete job=(200 skilled man-days)(1.75 unskilled man days/skilled man day)
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complete job=350 unskilled man-days
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For 3 unskilled men:
complete job=350 unskilled man-days/3 unskilled men=116.7 days
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ANSWER: It would take 3 unskilled men 116.7 days to complete the job.