Eleven Plus (11+) in Essex
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slush
Posts: 18 Joined: Wed Jan 11, 2012 9:36 pm
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by slush » Fri Mar 09, 2012 9:27 am
Hi
Would anyone be kind enough to help with this maths question.
8 people take 10 hours to do a certain job, how long would it take 20 people to do the same job?
Thanks You
Minesatea
Posts: 1234 Joined: Sat Oct 31, 2009 12:08 am
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by Minesatea » Fri Mar 09, 2012 9:41 am
Not sure, but:
If 8 people take 10 hours each that is 80 man hours in total ie 1 man would take 80 hours to do the job.
20 people should thus take 80 / 20 = 4 hours
I think!
NOTLEY PARENTS
Posts: 178 Joined: Wed Sep 23, 2009 3:09 pm
Location: Great Notley
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by NOTLEY PARENTS » Fri Mar 09, 2012 10:42 am
Minesatea wrote: Not sure, but:
If 8 people take 10 hours each that is 80 man hours in total ie 1 man would take 80 hours to do the job.
20 people should thus take 80 / 20 = 4 hours
I think!
I make it 4 hours too.
arsen
Posts: 25 Joined: Sat Nov 19, 2011 7:14 pm
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by arsen » Fri Mar 09, 2012 3:43 pm
It is 4 hours.
You are basically increasing the number of people by a factor of 2.5. (8x2.5=20), therefore you would be decreasing the time taken by 2.5. So 10/2.5 = 4
Hope helps!