<p>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?</p>
<p>is the answer (8/3)? if so, i got it by looking at the distance that 86 is from 92 and 70. Its 16=p away from 86 and 6=n away from 92. Therefore, p/n = 16/6 or 8/3. if this is wrong im sorry but it is what i would have done...</p>
<p>no, the answer is 3/8 o_o close though lol</p>
<p>Where is it in the BlueBook?</p>
<p>test 6 section 3</p>
<p>No it is actually 3/8. You can't set p equal to 16 and n equal to 6. You could use the two numbers to find the ratio like you did though. After that You have to use common sense to realize that n must be larger because it is closer to 86. By the way, when the numbers aren't so easy to decipher just use the equation 70x + 92(1-x) = 86. That will give you the percentages from which you can find the ratio.</p>
<p>You know that 70p and 92n are the test scores (not avg) of the classes because: if x is the total of the test scores and p is the number of kids then x/p = 70, x = 70p.</p>
<p>It says the avg score is 86 so:
(70p + 92n) / (p + n) = 86, solve for p/n
70p + 92n = 86p + 86n
16p = 6n
16p/n = 6
p/n = 3/8</p>
<p>The total of the p test scores is 70p, and the total of the n test scores is 92n. The overall average score for both classes combined, 86, is the total of all the test scores, 70p+92n, divded by the total number of scores, p + n. Therefore 70p+92n/p+n=86, which simplifies to 70p+92p = 86p + 86n, and further to 6n = 16p. Therefore, p/n = 6/16 = 3/8.</p>
<p>Thanks guys.</p>
<p>does it work the way i did it if you always just flip the fraction? or was this just a coincidence?</p>