GMAT数学From a group of 3 boys and 3 girls, 4 children are to
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GMAT数学
From a group of 3 boys and 3 girls, 4 children are to be randomly selected. What is the probability that equal numbers of boys and girls will be selected?
A. 1/10
B. 4/9
C. 1/2
D. 3/5
E. 2/3
From a group of 3 boys and 3 girls, 4 children are to be randomly selected. What is the probability that equal numbers of boys and girls will be selected?
A. 1/10
B. 4/9
C. 1/2
D. 3/5
E. 2/3
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wangalong231 共回答了24个问题
|采纳率91.7%- 9除以15,分母是6个里面去4个,就是15种情况,分子是3C2乘以3C2,选D
- 1年前
jpjm 共回答了13个问题
|采纳率84.6%- 从6个人中选4个人的情况数为15(可以数出来,也可以用排列组合算),选出的4个人为2男2女的情况数为9(等于从3个男生中选2个的情况数乘以从4个女生中选2个的情况数,可以数出来,也可以用排列组合算出来)
- 1年前
经典户型 共回答了14个问题
|采纳率85.7%- 首先翻译问题:
从3个男孩和3个女孩里随机选出4个孩子。选出的4个孩子中男孩女孩的数量相同的机率是多少?
恩。。就是排列么。
总共的情况数量:六选四,6C4(都是下标)=6!/4!=6*5/2=15
然后看男孩:三选二,3C2=3!/2!=3
女孩:三选二,3C2=3!/2!=3
选出两男两女就用男孩的情况乘以女孩的数量就好了啊。
所以几率就... - 1年前
天印之冷 共回答了20个问题
|采纳率80%- E
- 1年前
zjh_lym 共回答了17个问题
|采纳率88.2%- 从一组3男孩和3个女孩, 4名儿童将随机选取。什么是概率同等数目的男孩和女孩将选定的? 2/3
选D - 1年前
五羊雪糕127 共回答了25个问题
|采纳率88%- 楼主,是这样的:
这是一道简单的组合问题,3男3女共6人中选4人,要男女一样,则必然是男2人,女2人.也就是用3个男中选2男的组合数乘以3女中选2女的组合数再除以总的组合数,也就是6人中任选4人的组合数,就是男女相等的概率了!
算式如下:
(3C2)*(3C2)/(6C4)
结果也就是:3*3/15=3/5 选C
注:由于不方便输入公式,组合符号后... - 1年前
你因帅被判刑 共回答了17个问题
|采纳率82.4%- 从3个男孩里选2个有以下几种组合方式:
(3x2)/2=3
从3个男孩和3个女孩里各选2个有以下几种组合方式:
3x3=9
从6个孩子里选4个有以下几种组合方式:
(6x5x4x3)/(4x3x2)=15
Probability that equal numbers of boys and girls will be selected:9/15=3/... - 1年前
睡觉12879 共回答了24个问题
|采纳率83.3%- 不知道你题目看懂了没,我现将题目解释一遍:
从一个由3个男孩和3个女孩组成的小组中,随机选取4个小孩。其中选取的小孩中男孩和女孩个数相等的概率是多少?
从6个人中选4个人,共有C(6)4=6!/4!=15种方法
从6个人中选两男两女,共有[C(3)2]^2=9种方法
所以所求概率为9/15=3/5,选D... - 1年前
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