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UID509437在线时间 小时注册时间2010-2-7最后登录1970-1-1主题帖子性别保密 
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| each of the 25balls in a certain box is either red ,blue or white and has a number from 1 to10 painted on it. if one ball is slected at ramdom from box, what is probablity that the ball selected will either be white or have a even number painted on it? 
 (1 the probablity that the ball will both be white and have a even number painted on it is 0.
 2)  the probablity that the ball will be white minus the probablity that the ball will have a even number painted on it is 0.2.
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