回复：If you are right,it shoul be from real data.P(b)=13/27

来源: 于 2010-05-28 12:51:57 [旧帖] [给我悄悄话] 本文已被阅读：次

I believe this is the ‘expected’ answer to this question. You can always argue that the question was not soundly stated though (though actually it is generally soundly stated).

13/27 is a right answer

1/3 could be a right answer…

½ could be a right answer …

要真正完全理解这道题，

1- 应明白这三个答案的来龙去脉
2- 你应可以扩展或改写题目，create a scenario/story/question that make 1/3 and ½ correct.