2007 AMC 12B Problems/Problem 12
Problem 12
A teacher gave a test to a class in which $10%$ (Error compiling LaTeX. Unknown error_msg) of the students are juniors and $90%$ (Error compiling LaTeX. Unknown error_msg) are seniors. The average score on the test was 
. The juniors all received the same score, and the average score of the seniors was 
. What score did each of the juniors receive on the test?
Solution
Taking a weighted average
where x is the Juniors' score
$\begin{align*}x & = 10(84 - .9(83) \\ & = 840 - 9(83) \\ & = 93 \Rightarrow \mathrm {(C)}$ (Error compiling LaTeX. Unknown error_msg)
