China Mathematical Olympiad 1989 problem5
Source: China Mathematical Olympiad 1989 problem5
October 29, 2013
combinatorics unsolvedcombinatorics
Problem Statement
Given points in the space, any three of them are not collinear. We divide these points into groups such that the numbers of points in these groups are different from each other. Consider those triangles whose vertices are points belong to three different groups among the . Determine the numbers of points of each group such that the number of such triangles attains a maximum.