Link to MSN's SAT Math Problem:
There are certain types of questions that a student will encounter on every SAT math test. The problem MSN selected as one of the most difficult questions is actually found on every test. It is not that difficult if you know how to tackle it. Our test preparation will teach you how to solve math problems such as this one.
The average is found by taking the total divided by the number of entries.
(70p +92n)/ (n+p) = 86
70p+92n = 86 (n+p) Cross Multiply
70p+92n = 86n +86p Distribute
6n = 16p Combine Like Terms
6n / 16 = p Divide
(6n/16)/n Substitute value of p into the equation and the answer of p/n = 6/16