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Haven
Senior Member

USA
28 Posts

Posted - 04/22/2008 :  11:33:39  Show Profile  Reply with Quote
The average (arithmetic mean) of the test scores of a class of "p" students is 70, and the average of the test scores of a class of "n" students is 92. When the scores of both classes are combined the aveage is 86. What is the value of p n?

There was no answer or explaination given for this problem.
I would like a step by step explaination if possible so that I can explain this problem to students I sometimes tutor.

Also, it was asked if prime factoring can be used to solve this problem?

Thanks for any and all help.

Haven Williams
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Subhotosh Khan
Advanced Member

USA
9117 Posts

Posted - 04/22/2008 :  12:08:13  Show Profile  Reply with Quote
quote:
Originally posted by Haven

The average (arithmetic mean) of the test scores of a class of "p" students is 70, and the average of the test scores of a class of "n" students is 92. When the scores of both classes are combined the aveage is 86. What is the value of p n?

There was no answer or explaination given for this problem.
I would like a step by step explaination if possible so that I can explain this problem to students I sometimes tutor.

Also, it was asked if prime factoring can be used to solve this problem?

Thanks for any and all help.

Haven Williams


This is not a difficult problem:

Start from the definition of average and form the equation

p*70 + n*92 = (n+p)*86

Now show us where do you go from here.
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Haven
Senior Member

USA
28 Posts

Posted - 04/23/2008 :  10:30:33  Show Profile  Reply with Quote
I am not sure what you mean? I found the answer and it was 3 8
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Subhotosh Khan
Advanced Member

USA
9117 Posts

Posted - 04/23/2008 :  13:43:27  Show Profile  Reply with Quote
quote:
Originally posted by Haven

I am not sure what you mean? I found the answer and it was 3 8<<<Correct

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