25

Part of 1968 IMO Shortlist

Problems(1)

Find the maximum possible number of triangles

Source:

k

l_1, \ldots, l_k

n_i

points on the line

l_i, i = 1, 2, \ldots, k

, find the maximum possible number of triangles with vertices at these points.

combinatoricsgeometrycountingIMO Shortlist