OG12th DS 128

zhengxing

A school administrator will assign each students 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.

The answer is B. Why?

zhengxing

thank you  !!!!!

Fabulous

 题目说了半天，其实就是问，

3<m<13<n, n是否能整除m？条件1，3n能整除m；条件2，13n能整除m。

这就简单了，m的取值可以是2，3，4，5，6，7，8，9，10，11，12，这样，根据条件1，3n能整除m，无法判断出n是否能整除m，因为m有可能是6，9，或者12。但是条件2，13n可能 整除m的话，并且m的取值中没有能整除13被13整除的，这就说明13n中的n一定正整除m。所以条件2可以判断