MathDB
Flanders 6 ('97)

Source:

September 7, 2003
geometrygeometric transformationreflectionalgebra solvedalgebra

Problem Statement

Thirteen birds arrive and sit down in a plane. It's known that from each 5-tuple of birds, at least four birds sit on a circle. Determine the greatest Māˆˆ{1,2,...,13}M \in \{1, 2, ..., 13\} such that from these 13 birds, at least MM birds sit on a circle, but not necessarily M+1M + 1 birds sit on a circle. (prove that your MM is optimal)
Back to ProblemsView on AoPS