Feifei 4-15? help...

sbbi · 发表于 2003-8-31 00:07:00

"15. There are six cards each with a number from 1 to 6. Draw one card randomly and then put it back into a bowl. If one card is to be drawn randomly, and the sum of two cards is 8, what’s the probability that the card is 5?

2 6
6 2
4 4
5 3
3 5

P=2/5"

My answer"
4 4 should happen twice as:

2 6
6 2
4 4
4 4
5 3
3 5

P=1/3
Do I miss anything? thx

sbbi · 发表于 2003-9-1 10:15:00

请牛牛们看看好吗?

anchoret · 发表于 2003-9-1 11:30:00

i think the 4,4 is of the same probability as 2,6, both are 1/36.

so it should be 2/5

sbbi · 发表于 2003-9-1 11:34:00

2 and 6 could be "2 6" and "6 2", so 4 and 4 could be "4 4" and "4 4" (twice)

so it should be 2/6

did I miss anything?

以下是引用anchoret在2003-9-1 11:30:00的发言：
i think the 4,4 is of the same probability as 2,6, both are 1/36.

so it should be 2/5

anchoret · 发表于 2003-9-1 11:46:00

画一个表格（6*6），表示所有概率，看看4,4出现几次？

2，6和6，2是不同的（前一个就不同），4，4却总是代表前一个取4，后一个再取4的概率

[此贴子已经被作者于2003-9-1 11:48:33编辑过]

slickwx · 发表于 2006-7-4 18:24:00

问的是ONE CARD的概率啊,应该是1/5才对啊.2/5是说2张CARD中有5出现的概率.

sa009 · 发表于 2006-12-3 09:57:00

2/5
2，6； 3，5；4，4；5，3； 6，2

jellysun · 发表于 2007-3-15 18:13:00

我同意是1/5
因为题目说what's the possibility that the card is 5
"the card" should refer to the second card drawn.
to be discussed..

zxzhyzcy · 发表于 2007-5-28 19:58:00

请问这种题意理解的问题，是因为语法上的歧义，还是大家回忆jj时候的表述不清呢？

考试的时候会有这种问题出现不？

妖还在 · 发表于 2007-6-6 12:13:00

以下是引用jellysun在2007-3-15 18:13:00的发言：
我同意是1/5
因为题目说what's the possibility that the card is 5
"the card" should refer to the second card drawn.
to be discussed..

我同意这个观点....

因为这种读题造成的困绕而做错真是烦人

唉~郁闷

Feifei 4-15? help...

Feifei 4-15? help...

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