a school administor will asign each student of a group of N students to one of M classroom. if 3<m<13<n if the students could be evenly distributed in the classroom?

1 student of a group of 3N could be distributed to M classrooms

2 ............13N could be distibuted to M..

想了半天没有找到方法`````

我觉得是1不充分2充分

因为13N可以被M整除 13是个质数 M又小于13 那么13必定不能被M整除 则N可以被M整除 所以2充分

但是1就不行 举个反例就行 M=9 N=15 这样3N能被M整除 但N显然是不能被M整除的