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1设盒中有10个木质球,6个玻璃球,木质球有3个红球,7个蓝色;玻璃球有2个红色,4个蓝色。现在从盒中任取一球,用A表示“取到蓝色球”,B表示“取到玻璃球”,则P(B|A)=( )。
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2设A、B为两个事件,
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,且
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,则下列必成立是( )。
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3有6本中文书和4本外文书,任意往书架摆放,则4本外文书放在一起的概率是( )。
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4A、B为两事件,若
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,则( )。
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5已知事件A、B满足
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,则
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( )。
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B.
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6设10件产品中有4件不合格品,从中任取2件,已知所取的2件产品中有一件是不合格品,则另一件也是不合格品的概率为( )。
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7设A、B为两个随机事件,且
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,则必有( )。
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8设A,B是两个相互独立的事件,,
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则一定有
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( )。
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9甲、乙两人各自考上大学的概率分别为0.7,0.8,则两人同时考上大学的概率是( )。
A.0.75
B.0.56
C.0.5O
D.0.94
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10某人打靶的命中率为0.8,现独立的射击5次,那么5次中有2次命中的概率是( )。
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