求解~谢谢啦~

secretnancy

143. 14954-!-item-!-187;#058&010212
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?
(A) 96
(B) 48
(C) 32
(D) 24
(E) 18

多谢啦

fangpyj8906

个人理解这题相当于就是X个人每人选两首个，一共选了12*4首歌，求X  即2X=12*4  X=24~~开始想到用排列组合了，怎么就解不出来

amanda621

lz一项成一共48 首歌  没人挑两首 一共多少人挑完……