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袋子中装有3个红球,5个黄球,1个白球,这些球的形状、大小、质地等完全相同,随机...
袋子中装有3个红球,5个黄球,1个白球,这些球的形状、大小、质地等完全相同,随机地从袋子中摸出一个红球的概率是 .
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