将一个骰子连续投掷三次，它落地时向上的点数依次成等比数列的概_爱下问搜题

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问题选择题

将一个骰子连续投掷三次，它落地时向上的点数依次成等比数列的概率是（　　）

A．

1

12

B．

1

15

C．

1

18

D．

1

27

答案

根据题意，将一个骰子连续抛掷三次，每次都有6种情况，则共有6³=216种情况，

它落地时向上的点数能组成等比数列，分两种情况讨论：若三次的点数都相同，有6种情况，

若三次的点数不相同，则这三次的点数分别为1，2，4，或着是4，2，1，共两种情况．

故它落地时向上的点数能组成等比数列的情况共有8种．

由此可得它落地时向上的点数依次成等比数列的概率是

8

216

=

1

27

，

故选D．

单项选择题

下焦瘀热，损伤膀胱血络，尿中带血，赤涩热痛，舌红，脉数。治宜选用( )

A．八正散
B．小蓟饮子
C．导赤散
D．龙胆泻肝汤
E．萆薜分清饮

改错题

下面短文中有10处错误。请在有错误的地方增加、删除或修改某个单词。

增加：在缺词处加上一个漏字符号（∧），并在其下面写出该加的词。

删除：把多余的词用斜线（\）划掉。

修改：在错的词下划一横线，并在该词下面写出修改后的词。

注意：1 每处错误及其修改均仅限一词。

2 只允许修改10处，多者（从第11处起）不记分。

Liu Kai is a good student and always ready for help others. One day on his way to school, he

saw little girl crossed the road. A car was coming towards him quickly and the girl was very frightened to move. Just now Liu Kai rushed up to her and caught her on the arm. The little girl was saved. She told him where she lived in, and he took her home. When Liu Kai hurried into the classroom, the teacher has already begun his lesson. He told the teacher why he was late. He was then praised for which he had done.