子机构
400-600-1123
logo
备考资讯 提分课程 答疑社区
登录
注册
题库解析   >   排列组合 题型   >  
本题由2提供

If each of the 12 teams participating in a certain tournament plays exactly one game with each of the other teams, how many games will be played?


     A. 144 

     B. 132  

     C. 66 

     D. 33  

     E. 23


登录申友雷哥GMAT,查看答案及解析

视频解析

资深讲师题题有解析

播放器加载失败: 未检测到Flash Player,请到安装
00:00 / 00:00

文字解析

答案:
C

Arithmetic E

lementary Combinatorics

Since each of the 12 teams will play exactly one game with each of the other teams, the number of games that will be played is equal to the number of selections of 2 teams, without regard to order, from 12 teams. This is the number of combinations of 12 teams taken 2 at a time, which is equal to image.png.

Alternatively, each of the 12 teams will play each of the 11 other teams. The product (12)(11) counts each of the games twice since, for example, this product separately counts “Team A plays Team B” and “Team B plays Team A”. Therefore, the number of games that will be played isimage.png .

The correct answer is C.


GMAT会员

提交
    OG视频
    申友雷哥GMAT小助手

    添加官方小助手微信
    了解更多GMAT考试与咨询

    吉祥物小蜜蜂

    关注公众号

    公众号

    扫码关注申友雷哥GMAT公众号

    立即获取12GGMAT核心资料

    微信咨询

    申友在线咨询二维码图片

    扫码添加申友雷哥GMAT官方助手

    立即咨询GMAT网课面授课程

    联系申友雷哥 全国免费咨询热线:400-600-1123

    Copyright © 2021 All Right Reserved 申友雷哥教育 版权所有 沪ICP备17005516号-3 免责声明 互联网经营许可证编号:沪B2-20210282