MathDB

(423) 4

Part of 1994 Tournament Of Towns

Problems(1)

TOT 423 1994 Autumn O J4 20 pupils in the Backwoods school

Source:

6/12/2024
There are 2020 pupils in the Backwoods school. Any two of them have a common grandfather. Prove that there exist 1414 pupils all of whom have a common grandfather.
(AV Shapovalov)
combinatorics