问题 解答题

5个海盗抢到了100颗宝石,每一颗都一样的大小和价值连城.他们决定这么分:

A.抽签决定自己的号码(1,2,3,4,5)

B.首先,由1号提出分配方案,然后大家5人进行表决,当且仅当超过半数的人同意时(人数一样的时候算不通过),按照他的提案进行分配,否则将被扔入大海喂鲨鱼.

C.如果1号死后,再由2号提出分配方案,然后大家4人进行表决,当且仅当超过半数的人同意时,按照他的提案进行分配,否则将被扔入大海喂鲨鱼.

D.以此类推.条件:每个海盗都是很聪明的人,都能很理智的判断得失,从而做出选择.每个海盗都把生命视为第一重要!

问题:第一个海盗提出怎样的分配方案才能够使自己的收益最大化?

答案

①假设1、2、3号都死了,只剩4号和5号.这时无论4号怎么分(哪怕分5号100个),5号只要反对,4号就死了(因为没有超过半数同意,非要大于50%才行),4号的生命得不到保障,所以,4号不能让3号死,3号死了4号就危险,所以,3号不论怎么分,4号都得同意.
②假设1、2号死了,3号来分的话,他肯定分自己100个,4号和5号都0个,因为3号肯定同意,4号也必须同意,就有大于50%的选票.
③假设1号死了,2号来分.2号肯定不会收买3号,收买4号和5号更好些,因为只要给他们1人1个,4号和5号就都得同意(由假设2,2号死了的话,4号和5号一个也分不到,现在2号给了他们1人1个,他们只得同意,2号会这么分:98、0、1、1).
④假设1号来分,他不会收买2号,那起码要给2号99个才行,他肯定会收买3号,因为给3号1个,3号就会同意1号的分法,3号要是不同意,1号死了2号分的话,3号一个也得不到,这时1号只要再收买4号和5号中任何一人就行了,给这个人两个,他就必须同意.
所以,1号的分配方案为:97、0、1、2、0 或97、0、1、0、2.

答:第一个海盗提出依次是:97,0,1,0,2; 或者是:97,0,1,2,0的分配方案才能够使自己的收益最大化.

阅读理解

     December 2

     Sharon called about four times today. At least it shows she's trying to explain something to me. I feel

a little better.

     December 3

     This morning Sharon said she had only told one person and didn't know why everyone seemed to

know. Yes, I am an adopted (收养的) daughter. But she had promised to keep it a secret for ever!

     December 5

     I wish I had a friend I could really trust all of the time. I thought I found that friend, but I haven't and

it's making me miserable (痛苦的)! It's wrong to tell her all about it. She gains my trust, and then loses it.

     December 7

     I have a nice room, beautiful house and everything I've ever wanted. My adoptive parents will give

me all the things I've ever dreamed of. Yet all the money in the world can't buy what I want now. I want

for Sharon to be my best friend again.

     December 10

     Sharon just called. She said she thought it might help if we spent more time together. She worried

that I would switch schools (转学). She is the best friend I've ever had. When I'm with Sharon, I can

be myself. I need Sharon's friendship. I need it more than I've ever known.

     December 16

     I just had the most fantastic two days of my life! This was the best time I've had for a long, long while. Yesterday, we walked five times around the park and today we walked along the river for twenty minutes. We talked so much. Sharon, Sharon, no brick wall between us now.

1. What is the author mainly worried about?

A. How she was adopted.      

B. Why she switched schools.

C. Her family life.      

D. Her friendship with Sharon.

2. Sharon lost the author's trust because she ________.

A. didn't keep the author's secret      

B. didn't like the author any more

C. told the author's past life to everyone  

D. often refused to help the author

3. The underlined word "fantastic" in the last paragraph probably means ________.

A. funny

B. wonderful

C. sad

D. lucky

4. It can be inferred that in the end the author and Sharon ________.

A. were not friends anymore      

B. became good friends again

C. would switch to another school together  

D. could hardly understand each other

单项选择题