Question: On a horse track with 5 lanes and 25 horses without having stopwatch you need to find the 3 faster horses assuming that each horse will run with the same performance each time it races. What is the minimum number of races that need to take place.
Answer: The answer is 7
1) Make 5 random groups (group A-E) of 5 horses and make them race. (5 races so far).
• Note down the positions of each of the horses
• Horses finishing in positions 4-5 can no longer claim positions 1-3 so scrap them out
2) Make a race of the fastest horse of each of the previous 5 races .(6 races so far)
• Winner of this race is takes position 1st of all 25 horses
• Horses finishing 4th-5th can no longer claim positions 2nd-3rd so scrap them out
3) Now you need to find the positions 2nd-3rd. 5 horses will compete for the places 2nd-3rd .(6 races so far)
• Horses that finished at positions 2nd-3rd at race 6 (B1-C1) can run to claim up to the position they finished at race 6.
• Horses that raced initially against the horse that came 1st in race 6(A1) can now race for positions 2-3. (So include A2,A3)
• Horses that raced initially against the horse that came 2nd in race 6 (B1) can now race for position 3. (So include B2)