25 horses, 5 tracks

MediumBrainteasers~8m

You have 25 horses and a track that races 5 at a time, giving only the finishing order (no times). What is the minimum number of races to find the top 3 fastest horses?

Show hints (2)+
  1. First find the 5 group winners.
  2. After ranking the winners, prune horses that cannot be top 3.

Answer

Reveal answer →

7

Want the full step-by-step worked solution? It's part of Premium — along with a worked solution for every question in the bank.

Asked at: Jane Street, Citadel, Two Sigma

Related questions