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标题: 求助PREP里面的一道数学题 [打印本页]

作者: haywood2013 时间: 2013-11-10 20:50
标题: 求助PREP里面的一道数学题

做题做晕了，麻烦哪位大神帮忙看下这道题的答案该是多少？谢谢

A certain junior class has 1,000 students and a certain seniorclass has 800 students. Among thesestudents, there are 60 sibling pairs, each consisting of 1 junior and 1senior. If 1 student is to be selectedat random from each class, what is the probability that the 2 students selectedwill be a sibling pair?

作者: red1358 时间: 2013-11-10 21:46
有哪些选项呢？

作者: haywood2013 时间: 2013-11-10 22:26
来自Prep-Math破解版 PS1 116题。原始文档这题的选项都是空白

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