求助TTGWD16－7（同TTGWD15-28）

A school administrator will assign each student in a group of n students to one of m classrooms.  If 3 < m < 13 < n, is it possible to assign each of the n students to one of the m classrooms so that each classroom has the same number of students assigned to it?

(1)   It is possible to assign each of 3n students to one of m classrooms so that each classroom has the same number of students assigned to it.

(2)   It is possible to assign each of 13n students to one of m classrooms so that each classroom has the same number of students assigned to it.

A. Statement (1) ALONE is sufficient, but statement (2) alone is not sufficient.

B. Statement (2) ALONE is sufficient, but statement (1) alone is not sufficient.

C. BOTH statements TOGETHER are sufficient, but NEITHER statement ALONE is sufficient.

D. EACH statement ALONE is sufficient.

E. Statements (1) and (2) TOGETHER are NOT sufficient.

答案是B，但是没思路，感觉是D。请求指点

其实就是咱平时做那个余数题啊

3 < m < 13 < n     n是否能被m整除？

条件一 3n能被m整除

条件二  13n能被m整除

A school administrator will assign each student in a group of n
students to one of m classrooms.  If 3 < m < 13 < n,
is it possible
            to assign each of the n
students to one of the m classrooms so that each classroom has the same
number of students assigned to it?       

(1)   It is possible to
assign each of 3n students to one of m classrooms so that each
classroom has the same number of students assigned to it.

(2)   It is possible to
assign each of 13n students to one of m classrooms so that each
classroom has the same number of students assigned to it.

条件一： 3n/m为整数，举反例：当n=20,m=6时，n/m不是整数，所以不能恰好分配到每个班级；当n=18,m=6时，可以，所以不确定，则错。