SOLUTION: Three workers can do a job in 28 hours. How many more workers are needed to do this job in 12 hours?

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Question 1027713: Three workers can do a job in 28 hours. How many more workers are needed to do this job in 12 hours?

Found 2 solutions by macston, Edwin McCravy:
Answer by macston(5194) About Me  (Show Source):
You can put this solution on YOUR website!
.
x=number of workers for 12 hours
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3%2F28=x%2F12 . Cross multiply.
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28x=36 . Divide each side by 28.
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x=36%2F28=1.29 workers
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Answer by Edwin McCravy(20081) About Me  (Show Source):
You can put this solution on YOUR website!
The other tutor's answer is very wrong.

Three workers can do a job in 28 hours. How many more workers
are needed to do this job in 12 hours?
The fewer workers there are the more the hours that are required, 
and the more workers there are, the fewer hours that are required.

Therefore workers and hours are inversely proportional.

The word "inversely" is a form of the word "invert".
So we invert one of the fractions in the proportion. It doesn't
matter which one we invert.



matrix%281%2C3%2C%0D%0A%0D%0A3%2Fx%2C%22%22=%22%22%2C12%2F28%29

matrix%281%2C3%2C%0D%0A%0D%0A12x%2C%22%22=%22%22%2C84%29

matrix%281%2C3%2C%0D%0A%0D%0Ax%2C%22%22=%22%22%2C7%29

7 workers are required, so we need 7-3 or 4 more workers.  

Edwin