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Word Translations -- Help!!

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Word Translations -- Help!!

by ramonsa » Fri May 08, 2009 6:54 pm
Can someone explain me this problem?... please!

For the past n days, the average (arithmetic mean) daily production at a company was 50 units. If today's production of 90 units raises the average to 55 units per day, what is the value of n?

Thanks
Ramon
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by vitaly » Fri May 08, 2009 9:59 pm
Let's say a1,...,an are daily productions for the past 1...n days accordingly.

Then average for the past n days is (a1+...+an)/n = 50

Average for the past n days AND today will be
(a1+...+an+90)/(n+1) = 55

Left part is equal to
(a1+...+an)/(n+1)+90/(n+1)=(a1+...+an)*n/n(n+1)+90/(n+1)= (50n+90)/(n+1)

Now you need to solve this equation: (50n+90)/(n+1) = 55
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Re: Word Translations -- Help!!

by pnanu » Tue May 12, 2009 4:59 am
I am not the best Maths guy. But here is a more simple way to get the answer

x/n=50
Therefore x=50n

x+90/ n+1 = 55

now substitute for X, then you get

50n + 90 / n+1 = 55

Resulting into n = 7
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by mcdesty » Mon Dec 17, 2012 8:10 pm
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by mcdesty » Mon Dec 17, 2012 8:11 pm
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by puneetkhurana2000 » Mon Dec 17, 2012 8:52 pm
You can treat this as a mixture problem and get the answer as:-

(90-55)/(55-50)=n/1, Solving we get n = 7.
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