（6分）某初级中学准备随机选出七、八、九三个年级各1名学生担任领操员．现已知这三...

（6分）某初级中学准备随机选出七、八、九三个年级各1名学生担任领操员．现已知这三个年级分别选送一男、一女共6名学生为备选人.

1.（1）请你利用树状图或表格列出所有可能的选法；

2.（2）求选出“两男一女”三名领操员的概率．

1.解法一：（1）用表格列出所有可能结果：七年级八年级九年级结果男男男（男，男，男）男男女（男，男，女）男女男（男，女，男）男女女（男，女，女）女女女（女，女，女）女女男（女，女，男）女男女（女，男，女）女男男（女，男，男） ····································································································································· 3分解法二：（1）用树状图列出所有可能结果： ····································································································································· 3分 2.（2）从上表可知：共有8种结果，且每种结果都是等可能的，其中“两男一女”的结果有3种． 5分所以，P（两男一女）=．··························································································· 6分【解析】略

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