The best title for the passage is “ . Reaching the Top of the Mountain B. Standing at the Top of the Mountain Conversations between Father and Son D. How to Get to the Top of the Mountain C If you travel by air across the center of Africa or South America, you fly over forests for thousands of kilometers. These great forests are the oceans of trees. They are full of thousands and thousands of different kinds of plants and animals. However, the world forests are getting smaller all the time. We are cutting down the trees because we need wood, and we need more farmland. Some people say that there will not be any forests like these in 20 or 30 years. What will happen if they disappear? If we cut down our forests, a lot of plants and animals will disappear from the world. In a lot of places the new farmland will soon look like the old deserts. Crops will not grow there. It will not rain very often, and the weather will get very hot. Perhaps the climate of the world will change. This will be dangerous for everyone in the world. That is why we must take care of forests. 查看更多

 

题目列表(包括答案和解析)

某校设计了一个实验学科的实验考查:考生从6道备选题中一次性随机抽取3道题,按照题目要求独立完成全部实验操作.规定:至少正确完成其中2题的便可通过考查.已知6道备选题中,考生甲有4道题能正确完成,2道题不能完成;考生乙每题正确完成的概率都是
23
,且每题正确完成与否互不影响.
(Ⅰ)求考生甲通过实验考查的概率;
(Ⅱ)求乙考生至少正确完成2道题的概率.

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2010年11月广州成功举办了第十六届亚运会.在华南理工大学学生会举行的亚运知识有奖问答比赛中,甲、乙、丙同时回答一道有关亚运知识的问题,已知甲回答对这道题目的概率是
3
4
,甲、丙两人都回答错的概率是
1
12
,乙、丙两人都回答对的概率是
1
4

(1)求乙、丙两人各自回答对这道题目的概率.
(2)求回答对这道题目的人数的随机变量ξ的分布列和期望.

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某问答游戏的规则是:共5道选择题,基础分为50分,每答错一道题扣10分,答对不扣分.试分别用列表法、图象法、解析法表示一个参与者的得分y与答错题目道数x(x∈{0,1,2,3,4,5})之间的函数关系.

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某电视台的一个智力游戏节目中,有一道将中国四大名著A、B、C、D与它们的作者连线的题目,每本名著只能与一名作者连线,每名作者也只能与一本名著连线.每连对一个得3分,连错得-1分,一名观众随意连线,将他的得分记作ξ.
(Ⅰ)求该观众得分ξ为正数的概率;
(Ⅱ)求ξ的分布列及数学期望.

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甲、乙二人参加普法知识竞答,共有10个不同的题目,其中选择题6个,判断题4个.甲、乙二人依次各抽一题.
(1)甲抽到选择题、乙抽到判断题的概率是多少?
(2)甲、乙二人中至少有一人抽到选择题的概率是多少?

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