回复：经典好题 - 比三扇门和羊有趣-大家来讨论吧！

007 is too trick.What is expected value? If we get a box,there are two envelopes,one is x ,other is 10x,If we get x ,we change we earn 9x,if we get 10x we change,we lost 9x.So,changing expected value for earning is 0.This is not paradox,it is trick sentence but interesting.007 is funny.

所有跟帖： 

• 其实你说的这是简单的回答， 不是关键（欢迎排砖） -guest007- ♀ (599 bytes) () 06/19/2010 postreply 17:21:42

• You want to remind me oo/oo=oo? -jinjing- ♀ (483 bytes) () 06/19/2010 postreply 18:10:22