IMO 1964 Problem 5
- Day 2
Supppose five points in a plane are situated so that no two of the straight lines joining them are parallel, perpendicular, or coincident. From each point perpendiculars are drawn to all the lines joining the other four points. Determine the maxium number of intersections that these perpendiculars can have.
Official text Transcription from AI-MO AoPS, checked word for word against the official paper. Quoted with source.
Official text: IMO 1964 official English paper, page 1.
Solutions
No solution is on olymmath yet. Official and human solutions come first when they arrive. AI solutions come after them, with a label.