2. 外语
  3. Six people (two of them are John and Marry) are lined in a row. How many arrangements are there if John and Marry are at both en

Six people (two of them are John and Marry) are lined in a row. How many arrangements are there if John and Marry are at both en

admin2021-10-21  109
问题 Six people (two of them are John and Marry) are lined in a row. How many arrangements are there if John and Marry are at both ends of the row?
选项 A、720
B、30
C、48
D、2
E、24
答案C
解析 先考虑有限制的元素，J和M在两头，那么恰好是在两个位置上的全排列，为P22=2种，剩下的4个人在中间4个位置上全排列，为P44=24种，所以J和M在两头的排列一共有24×2=48种。
转载请注明原文地址:https://kaotiyun.com/show/lCtO777K
本试题收录于： GMAT QUANTITATIVE题库GMAT分类
0

GMAT QUANTITATIVE

GMAT

相关试题推荐
随机试题
最新回复(0)