In a certain group of people,3/8 of the people are men,and 2/3 of the men have brown eyes.If 3/4 of the people have brown eyes,then what fraction of the group are women whodo not have brown eyes?这不是条件概率的题呀,为什么我就是算不
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In a certain group of people,3/8 of the people are men,and 2/3 of the men have brown eyes.If 3/4 of the people have brown eyes,then what fraction of the group are women whodo not have brown eyes?这不是条件概率的题呀,为什么我就是算不
In a certain group of people,3/8 of the people are men,and 2/3 of the men have brown eyes.If 3/4 of the people have brown eyes,then what fraction of the group are women whodo not have brown eyes?这不是条件概率的题呀,为什么我就是算不出正确的那个答案
In a certain group of people,3/8 of the people are men,and 2/3 of the men have brown eyes.If 3/4 of the people have brown eyes,then what fraction of the group are women whodo not have brown eyes?这不是条件概率的题呀,为什么我就是算不
3/8*2/3=1/4
这里有四分之一的人Brown,一共有四分之三,所以有1/2是女性
女性一共占5/8
所以不是Brown的女性占的是
1-1/2/(5/8)=1/5
不是棕色眼睛的占五分之一
第一题大意是:从八个字母中选取三个,做排列组合,8*7*6=336,即总共能分给336个参与者,每个人的情况都不同。最后还有36种情况分不出去,显然一共有300个参与者。
第二题就是两列车2小时相遇,(1)(2)两种情况那种可以确定哪列车更接近终点:
情况(1):相遇时P车的平均速度是70mile/hour.说明相遇时已走过140miles,因为两车相对行驶,则Q车已走过110mi...
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第一题大意是:从八个字母中选取三个,做排列组合,8*7*6=336,即总共能分给336个参与者,每个人的情况都不同。最后还有36种情况分不出去,显然一共有300个参与者。
第二题就是两列车2小时相遇,(1)(2)两种情况那种可以确定哪列车更接近终点:
情况(1):相遇时P车的平均速度是70mile/hour.说明相遇时已走过140miles,因为两车相对行驶,则Q车已走过110miles,显然P车距终点更近。
情况(2):Q车在整个过程中平均速度是55miles,但并不清楚相遇前的平均速度,因而无法判断相遇时哪列车更接近终点。
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