b***k
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olivetree08 (olivia) 于 (Wed Sep 9 17:50:23 2009, 美东) 提到:
This one has been posted in the forum, however, if one changes the question,
how to solve?
三道门, 随机选一道, 如果门是关着的, 打开它; 如果门是打开的, 关上它.
每秒选一次. 问: 假设三道门都是关着的, 平均要过多久才能使三道门同时开着.
If you change the question: on average how long will three doors be opened
at least once (thought not necessarily simultaneously)?
Thanks very much for any insights.
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pcasnik (pcasnik) |
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