MathDB
P1- Second combinatorics exam of 2017 Iran MO 3rd round

Source: 2017 Iran MO 3rd round , second combinatorics exam P1

September 12, 2017
Irancombinatorics

Problem Statement

There are 100100 points on the circumference of a circle, arbitrarily labelled by 1,2,…,1001,2,\ldots,100. For each three points, call their triangle clockwise if the increasing order of them is in clockwise order. Prove that it is impossible to have exactly 20172017 clockwise triangles.
Back to ProblemsView on AoPS