SOLUTION: 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 cla

Algebra ->  College  -> Linear Algebra -> SOLUTION: 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 cla      Log On


   

Question 465204: 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 average score is 86. What is the value of "p/n"?
The answer is 3/8 or .375, but I do not understand how they got this answer. Can you help?
Answer by richard1234(7193) About Me  (Show Source):
You can put this solution on YOUR website!
We know that the sum of the scores from the p students is 70p, and the sum of the scores from the n students is 92n. Combining them,




We can split up the fraction two ways:





Hence, we are given




If we divide the first equation by the second, the 22's and the p+n's will cancel, and we will get

.