Question 1132323
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There are dozens of ways to solve this kind of problem.  Here is what I would do....<br>
A child takes twice as much time as a man to do the artwork.
So each child is worth half of a man.
Then 12 children are worth 6 men.
The given information then says that 18+6=24 men would take 9 days to finish the artwork.
24 men times 9 days equals 216 man-days.
216 man-days divided by 18 men equals 12 days.<br>
ANSWER: 12 days