APMO 2008/2

Discussion on Asian Pacific Mathematical Olympiad (APMO)
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Avik Roy
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APMO 2008/2

Unread post by Avik Roy » Thu Feb 03, 2011 11:40 am

Students in a class form groups each of which contains exactly three members such that any two distinct groups have at most one member in common. Prove that, when the class size is $46$, there is a set of $10$ students in which no group is properly contained.
"Je le vois, mais je ne le crois pas!" - Georg Ferdinand Ludwig Philipp Cantor

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