The Horse Race Problem

Puzzle: You have 25 horses and a track that can race 5 horses at a time. What is the minimum number of races needed to determine the top 3 horses?

Answer: 7 races are needed:

1. Race 5 groups of 5 horses (5 races).
2. Race the winners (1 race) to find the fastest.
3. Take the top 2 from the winner’s race, plus the 2nd and 3rd from the winner’s first race, and race them (1 race) to find 2nd and 3rd place overall.