Question

（6分）某初級中學準備隨機選出七、八、九三個年級各1名學生擔任領操員．現

已知這三個年級分別選送一男、一女共6名學生為備選人.

（1）請你利用樹狀圖或表格列出所有可能的選法；

（2）求選出“兩男一女”三名領操員的概率．

 

Answer 1

（1）①300···························································································· 1分

②21≤x≤22··························································································· 3分

③12····································································································· 4分

（2）2800×=2240（人）······························································ 5分

 

答：該區所有學生中口語成績為滿分的人數約為2240人．··································· 6分

解析:略