MathDB

6

Part of 2020 Costa Rica - Final Round

Problems(1)

10 persons around a circular table with 22 vases on it

Source: OLCOMA Costa Rica National Olympiad, Final Round, 2020 p6

3/26/2024
1010 persons sit around a circular table and on the table there are 2222 vases. Two persons can see each other if and only if there are no vases aligned with them. Prove that there are at least two people who can see each other.
combinatoricscombinatorial geometrygeometry