MathDB

1

Part of 1982 USAMO

Problems(1)

1982 USAMO #1

Source:

8/16/2011
In a party with 19821982 persons, among any group of four there is at least one person who knows each of the other three. What is the minimum number of people in the party who know everyone else?
AMCUSA(J)MOUSAMOcombinatorics unsolvedcombinatorics