曼哈顿的题目。。求大神解答

c87538 · 发表于 2015-8-12 08:57:29

In a room filled with 7 people, 4 people have exactly 1 sibling in the room and 3 people have exactly 2 siblings in the room. If two individuals are selected from the room at random, what is the probability that those two individuals are NOT sibling？

guoyilin2015 · 发表于 2015-8-12 11:14:02

DANIELLLLLL 发表于 2015-8-12 10:26
大神！我看了你几次数学解答，相当流弊！你的名字让我想起一位大神GL莫非是本尊降临？ ...

不是的，我也正沉沦在GMAT苦海。。

就是刷语文烦了来做做数学而已。。

tophoenix · 发表于 2015-8-12 10:46:54

提示: 作者被禁止或删除内容自动屏蔽

c87538 · 发表于 2015-8-12 10:36:28

guoyilin2015 发表于 2015-8-12 10:06
感觉数学刷真题OG和PREP足矣，没必要manhattan

懂啦。。thank you

DANIELLLLLL · 发表于 2015-8-12 10:26:27

guoyilin2015 发表于 2015-8-12 10:06
感觉数学刷真题OG和PREP足矣，没必要manhattan

大神！我看了你几次数学解答，相当流弊！你的名字让我想起一位大神GL莫非是本尊降临？

guoyilin2015 · 发表于 2015-8-12 10:06:47

c87538 发表于 2015-8-12 09:32
4 people have exactly 1 sibling in the room and 3 people have exactly 2 siblings in the room. 这 ...

感觉数学刷真题OG和PREP足矣，没必要manhattan

guoyilin2015 · 发表于 2015-8-12 10:04:39

c87538 发表于 2015-8-12 09:32
4 people have exactly 1 sibling in the room and 3 people have exactly 2 siblings in the room. 这 ...

sibling意为兄妹是相互关系

4个人有且只有一个sibling
那么两人一组 c1c2互为sibling b1b2互为sibling

3个人有且只有两个sibling同理
a1a2a3互为sibling

c87538 · 发表于 2015-8-12 09:32:21

guoyilin2015 发表于 2015-8-12 09:27
a1 a2 a3 b1 b2 c1 c2

Cxy是组合符

4 people have exactly 1 sibling in the room and 3 people have exactly 2 siblings in the room. 这两句话理解不了。。。能翻一下么

guoyilin2015 · 发表于 2015-8-12 09:27:55

a1 a2 a3 b1 b2 c1 c2

Cxy是组合符

1 - (C32 + C21 + C21) / C72 = 16/21

c87538 · 发表于 2015-8-12 09:23:15

继续顶

曼哈顿的题目。。求大神解答

所属分类: GMAT考试

正在浏览此版块的会员 ()

浏览过的版块

tophoenix tophoenix 当前离线 UID 400825 在线时间小时注册时间 2008-11-30 最后登录 1970-1-1 主题帖子性别保密	11^# 发表于 2015-8-12 10:46:54 \| 只看该作者提示: 作者被禁止或删除内容自动屏蔽

	回复同意！看一下！ Mark一下！举报