很可怕的题目，三个人算出三种答案，求高人指点！！

烈火青春

太可怕了，太可怕了，不知道是理解有问题，还是题目有问题，总之感觉答案算都算不出来！~

Six cards numbered from 1 to 6 are placed in an empty bowl.First one card is drawn and then put back into the bowl;then a second card is drawn.If the cards are drawn ar random and if the sum of the numbers on the cards is 8, what is the probability that one of the two cards drawn is numbered 5.


A 1/6            B 1/5          C 1/3         D 2/5         E 2/3

为嘛算出来有2/5的，有1/6的，就是没有1/5的！！！
求高人指点！！
最好别告诉我答案错了！答案是1/5
不过我宁可相信是答案错了~~~~~~~~~~

哑光

是2/5吧。。

哑光

http://forum.chasedream.com/GMAT_Math/thread-543836-1-1.html?postid=15041336&searchmode=TopicContent&searchtext=Six%20cards%20numbered%20from

旧帖。

烈火青春

哦也~
答案错鸟~

hugaoao

算出来是2/5= =不晓得对不对。。。

wyw1018

和为8总共5种排列： 2/6 3/5 4/4 5/3 6/2 其中2种有5 所以概率2/5

Heather_Lau

和为8总共5种排列： 2/6 3/5 4/4 5/3 6/2 其中2种有5 所以概率2/5

-- by 会员 wyw1018 (2011/9/6 2:07:06)

qilu8989

2/5