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Weight Average Mean

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AliciaSierra
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Weight Average Mean [#permalink] New post   24 Oct 2014, 12:27
Dear Experts,

Could you pls explain Weight average mean. Few people solve it using number line. I always get confuse with number line approach.

for example.
750———–o———–o———–X———–780

Thanks,
Ammu



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Re: Weight Average Mean [#permalink] New post   25 Oct 2014, 03:07
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Let's say there are 5 students with a score of 750 and 8 students with a score of 780. And if their combined average score for the class of 13 students is m, then the relationship between the quantities is as follows:

(780-m)/(m-750) = 5/8

Note 780 -m is the distance of the combined average from one end and m-750 is the distance from the other end. These quantities are in the same ratio as the weights on the opposite ends(here the number of students).

And the above equation is merely a rearrangement of the basic definition of the weighted average, which in this case would give us the average explicitly:

m = [8(780) + 5(750)]/[8+5]

Try rewriting this above equation in to the form of the first equation.

Cheers,
Dabral
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KarishmaB
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Re: Weight Average Mean [#permalink] New post   26 Oct 2014, 20:47
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ammuseeru wrote:
Dear Experts,

Could you pls explain Weight average mean. Few people solve it using number line. I always get confuse with number line approach.

for example.
750———–o———–o———–X———–780

Thanks,
Ammu


The number line approach boils down to this formula:

w1/w2 = (A2 - Aavg)/(Aavg - A1)

It has the efficiency of the number line approach but not its complication.

This is explained in detail here: https://www.gmatclub.com/forum/veritas-prep-resource-links-no-longer-available-399979.html#/2011/03 ... -averages/
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AliciaSierra
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Re: Weight Average Mean [#permalink] New post   27 Oct 2014, 09:44
VeritasPrepKarishma wrote:
ammuseeru wrote:
Dear Experts,

Could you pls explain Weight average mean. Few people solve it using number line. I always get confuse with number line approach.

for example.
750———–o———–o———–X———–780

Thanks,
Ammu


The number line approach boils down to this formula:

w1/w2 = (A2 - Aavg)/(Aavg - A1)

It has the efficiency of the number line approach but not its complication.

This is explained in detail here: https://www.gmatclub.com/forum/veritas-prep-resource-links-no-longer-available-399979.html#/2011/0 ... -averages/



Thank you Karishma. This is what i was looking for :)

Regards,
Ammu



Archived Topic
Hi there,
This topic has been closed and archived due to inactivity or violation of community quality standards. No more replies are possible here.
Where to now? Join ongoing discussions on thousands of quality questions in our Quantitative Questions Forum
Still interested in this question? Check out the "Best Topics" block above for a better discussion on this exact question, as well as several more related questions.
Thank you for understanding, and happy exploring!
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Re: Weight Average Mean [#permalink]
27 Oct 2014, 09:44
Moderator:
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Senior Moderator - Masters Forum
3137 posts

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