<p>Hey so if anyone could please explain how they got the answer to this problem that would be =).</p>
<p>PT6 Section 3, Question 18</p>
<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>Answer = 3/8, .375</p>
<ol>
<li><p>First average: x/p=70</p></li>
<li><p>cross multiply: x=70p</p></li>
<li><p>Second average: y/n=92</p></li>
<li><p>cross multiply: y=92n</p></li>
<li><p>Combined average: (70p+92n)/(p+n)=86</p></li>
<li><p>Cross multiply: 70p+92n=86p+86n</p></li>
<li><p>Subtract like terms: 6n=16p</p></li>
<li><p>Cross multiply: 6/16=p/n</p></li>
<li><p>Simply: 3/8=p/n=.375</p></li>
</ol>
<p>Thanks a lot</p>