2

Part of 1971 Kurschak Competition

Problems(1)

11 pairs from 22 points in plane

Source: 1971 Hungary - Kürschák Competition p2

22

points in the plane, no three collinear. Show that the points can be divided into

11

pairs, so that the

11

line segments defined by the pairs have at least five different intersections

combinatoricscombinatorial geometry