小学数学题

小学数学竞赛题：

Three kids A, B, C are playing a dice game. A goes first, B second, and
C third. The first person to roll a three wins and the game is over. The
dice are continuously passed in the above order until someone wins. What is the probability that C wins?

我可以用无限序列的公式做出来， 不过， 有别的方法吗？ 很好奇小学生怎么解这道题。

所有跟帖： 

• 回复：小学数学题 -endofsuburbia- ♂ (50 bytes) () 03/25/2009 postreply 17:17:26

• 多谢多谢。 -bujidao- ♂ (0 bytes) () 03/26/2009 postreply 09:29:39

• 这是哈佛大学某年的博士资格考试题嘛！ --闲云野鹤-- ♂ (0 bytes) () 03/26/2009 postreply 09:20:11