S*******s
发帖数: 13043 | 1 【 以下文字转载自 Parenting 讨论区 】
发信人: shanggj (shanggj), 信区: Parenting
标 题: 小学的概率数学题难死了.
发信站: BBS 未名空间站 (Fri Jan 10 13:08:00 2014, 美东)
在我女儿借的本书上见过, 女儿问我怎么回事. 我是完全糊涂了. 我好歹也是Ph.D.
呀.
记得题大概如下. 前提条件生男生女各50%概率.
Mrs. Smith is second grader Karen’s new math teacher. She is very nice
lady, Karen likes her very much.
1. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
What is the chance that Mrs. Smith has two daughters?
2. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
And Karen also heard Mrs. Smith one day mentioned that her daughter Jessica
loves skating.
What is the chance that Mrs. Smith has two daughters?
3. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
And Karen also heard Mrs. Smith one day mentioned that her daughter Jessica
loves skating. Then Karen found out her best buddy in the Sunday skate club,
Jessica, is actually Mrs. Smith’s daughter.
What is the chance that Mrs. Smith has two daughters?
4. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
And Karen also heard Mrs. Smith one day mentioned that her daughter Jessica
loves skating. On Sunday, Karen met Mrs. Smith with a girl at the movie
theater. Mrs. Smith said “Hi, Karen. This is my daughter Jessica, I told
you she also loves skating.”
What is the chance that Mrs. Smith has two daughters?
5. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
And Karen also heard Mrs. Smith one day mentioned that her daughter Jessica
loves skating.On Sunday, Karen met Mrs. Smith with a girl at the movie
theater. Karen asked Mrs. Smith “Mrs Smith, is this your daughter?” Mrs.
Smith said “Yes.”
What is the chance that Mrs. Smith has two daughters?
6. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
And Karen also heard Mrs. Smith one day mentioned that her daughter Jessica
loves skating. On Sunday, Karen met Mrs. Smith with a girl at the movie
theater. Karen asked Mrs. Smith “Mrs Smith, is this your daughter?” Mrs.
Smith said “Yes.” Karen asked the girl “I am Karen, what is your name?”.
“My name is Jessica.” The girl answered.
What is the chance that Mrs. Smith has two daughters?
正确答案给得是: (1) 1/4; (2) 1/3; (3) 1/3; (4) 1/3; (5) 1/2 ; (6) 1/3 ;
当然我不确定给出答案的人是不是真的搞清楚了. | S*******s
发帖数: 13043 | 2 没人回，是不是因为有答案了？再出个没答案的：
http://www.mitbbs.com/article/Parenting/32264199_0.html
在父母版看大妈们秀智商还是挺娱乐的。
【在 S*******s 的大作中提到】
: 【 以下文字转载自 Parenting 讨论区 】
: 发信人: shanggj (shanggj), 信区: Parenting
: 标 题: 小学的概率数学题难死了.
: 发信站: BBS 未名空间站 (Fri Jan 10 13:08:00 2014, 美东)
: 在我女儿借的本书上见过, 女儿问我怎么回事. 我是完全糊涂了. 我好歹也是Ph.D.
: 呀.
: 记得题大概如下. 前提条件生男生女各50%概率.
: Mrs. Smith is second grader Karen’s new math teacher. She is very nice
: lady, Karen likes her very much.
: 1. Karen heard from her classmate Maggie, that Mrs. Smith has two kids.
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