Difference between revisions of "Friends at a party"

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(Puzzle)
(Clarify that we're only talking about friends who are present at the party!)
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==Puzzle==
 
==Puzzle==
  
An extremely popular mathematician threw a party.  Including himself, there were 15 people at the party.  Must there have been two people there with the same number of friends?  Explain.
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An extremely popular mathematician threw a party.  Including himself, there were 15 people at the party.  Must there have been at least two people with the same number of friends present?  Explain.
  
 
[[Category: Graph theory]]
 
[[Category: Graph theory]]
 
[[Category: Pigeonhole principle]]
 
[[Category: Pigeonhole principle]]

Revision as of 06:17, 13 October 2010

Puzzle

An extremely popular mathematician threw a party. Including himself, there were 15 people at the party. Must there have been at least two people with the same number of friends present? Explain.