题目内容
(6分)为了庆祝六一儿童节,某食品厂制作了3种不同的精美卡片,每袋食品随机装入一张卡片,集齐三种卡片可获奖,现购买该种食品3袋,能获奖的概率是多少?
解:分别用卡1、卡2、卡3表示3张卡片,用“树状图”列出所有可能的结果:
---------------------------------------------------------------------------------------------------------(3分)
从树状图可以看出,一共有27种可能的结果,并且它们都是等可能的.“集齐三种卡片”记为事件B,它的发生有6种可能,··························································································(4分)
所以事件B的概率 ·······································································(6分)
即集齐三种卡片的概率是.
---------------------------------------------------------------------------------------------------------(3分)
从树状图可以看出,一共有27种可能的结果,并且它们都是等可能的.“集齐三种卡片”记为事件B,它的发生有6种可能,··························································································(4分)
所以事件B的概率 ·······································································(6分)
即集齐三种卡片的概率是.
略
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