Author 
Topic 

Haven
Senior Member
USA
28 Posts 
Posted  04/22/2008 : 11:33:39

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 


Subhotosh Khan
Advanced Member
USA
9116 Posts 
Posted  04/22/2008 : 12:08:13

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. 


Haven
Senior Member
USA
28 Posts 
Posted  04/23/2008 : 10:30:33

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


Subhotosh Khan
Advanced Member
USA
9116 Posts 
Posted  04/23/2008 : 13:43:27

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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