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Plz solve:
3 men and 18 children together take 2 days to complete a piece of work.
How many days will 18 children alone take to complete the piece of work,
if 6 men alone can complete the piece of work in 3 days?
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Let m be the man's rate of work, in terms of , and
let c be the child's rate of work, in the same terms.
Then from the condition you have this system of equations
3m + 18c = , (1)
6m = . (2)
From (2), m = = .
Substitute it into (1). You will get
+ 18c = ---> + 18c = ---> 18c = = = .
Hence, c = = .
This is rate of work of one child.
So, 18 children will complete of the job in one day, and
it will take 3 days for them to complete the job.
Answer. 3 days.