题库搜索>问题求解PS-12234
A jar contains 16 marbles, of which 4 are red, 3 are blue, and the rest are yellow. If 2 marbles are to be selected at random from the jar, one at a time without being replaced, what is the probability that the first marble selected will be red and the second marble selected will be blue?
分析A选项
分析B选项
分析C选项
分析D选项
分析E选项
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暂无雷哥网文字解析
第一个选红的概率是4/16,第二个选蓝的概率是3/(16-1),两个概率之乘积即为题目所问的概率大小=(4/16)*(3/15)=1/20
440741oibgq
第二次取出的分母应该是 15，而不是12
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2020-09-17 07:50:02
Cancys
不放回的有序概率问题
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2019-07-11 16:27:34
shneggenhua
有序的排列组合：
A（4,1）*A(3,1)/A(2,16)=4!/3 * 3!/2! / (16!/14!)=1/20
无序的排列组合是C的
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2019-04-12 13:53:06
默默
两个同时发生时间的概率相乘
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2018-05-16 07:33:00
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问题求解PS
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题目信息2m15s
平均耗时
84.4%
平均正确率
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