Photo Finish
Five horses run a race. Every horse finishes, and any number of horses may tie with one another at any position. A result specifies, for each pair of horses, whether one finished ahead of the other or they tied. (For example "A and C tie for first, then B, then D and E tie" is one result.) How many different results are possible? Give an integer.
Related problems & prerequisites
Worth solving first
- Partitioning a Set 5.0/10
- No Two Alike in a Row 5.0/10
- The Frog and Twenty Pads 5.0/10
Source: Classic exercise in wide circulation; no traceable original source. Statement written for AxiomIQ.