一道Prep題

In a survey of students, each student selected from a list of 12 songs the 2 songs that the student liked best.  If each song was selected 4 times, how many students were surveyed?

1) 96

2) 48

3) 32

4) 24

5) 18

Please help.  Thanks!!!

明白了，每个人选2个，N个人选出来的song的总和是12*4

所以N＝12*4/2

重要的是题意的理解，早上刚起来，题目觉得有点绕