Read the following SAT test question and then click on a button to select your answer.

In a class of 80 seniors, there are 3 boys for every 5 girls. In the junior class, there are 3 boys for every 2 girls. If the two classes combined have an equal number of boys and girls, how many students are in the junior class?

(A) 72
(B) 80
(C) 84
(D) 100
(E) 120

来源:可可英语 http://www.kekenet.com/sat/201406/304272.shtml