Question 347863
mark contracted 15 skilled workers to finish cementing a certain walk of uniform width in 16 days.
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Total man-days is 15*16 = 240
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after 8 days of work 15*8 = 120 man-days of work are completed
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With 6 men sick for 3 days, the 9 men complete 9*3 = 27 man-days
of work, leaving 93 man-days still to be done.

he wants the job to be on time .how many should he hire?" 
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There are 4 days remaining to do 223 man-days of work
93/4 = 24 1/4 men
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He needs 10 additional men.
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Cheers,
Stan H.