There are 25 mechanical horses and a single racetrack. Each horse completes the track in a pre-programmed time, and the horses all have different finishing times, unknown to you. You can race 5 horses at a time. After a race is over, you get a printout with the order the horses finished, but not the finishing times of the horses. What is the minimum number of races you need to identify the fastest 3 horses? I was suggested this puzzle via email by Terry Stickels. This is also a popular interview question at tech companies like Google. See a list of all sources in my blog post for this video: https://wp.me/p6aMk-58P Subscribe: null Send me suggestions by email (address in video). I consider all ideas though can't always reply! Why are there comments before the video is published? Get early access and support the channel on Patreon https://www.patreon.com/mindyourdecisions If you buy from the links below I may receive a commission for sales. This has no effect on the price for you. Show your support! Get a mug, a t-shirt, and more at Teespring, the official site for Mind Your Decisions merchandise: null My Books Mind Your Decisions: Five Book Compilation https://amzn.to/2pbJ4wR A collection of 5 books: "The Joy of Game Theory" rated 4.1/5 stars on 44 reviews http://amzn.to/1uQvA20 "The Irrationality Illusion: How To Make Smart Decisions And Overcome Bias" rated 3.5/5 stars on 4 reviews http://amzn.to/1o3FaAg "40 Paradoxes in Logic, Probability, and Game Theory" rated 4.4/5 stars on 13 reviews http://amzn.to/1LOCI4U "The Best Mental Math Tricks" rated 4.7/5 stars on 8 reviews http://amzn.to/18maAdo "Multiply Numbers By Drawing Lines" rated 4.3/5 stars on 6 reviews http://amzn.to/XRm7M4 Mind Your Puzzles: Collection Of Volumes 1 To 3 https://amzn.to/2mMdrJr A collection of 3 books: "Math Puzzles Volume 1" rated 4.4/5 stars on 13 reviews http://amzn.to/1GhUUSH "Math Puzzles Volume 2" rated 4.5/5 stars on 6 reviews http://amzn.to/1NKbyCs "Math Puzzles Volume 3" rated 4.1/5 stars on 7 reviews http://amzn.to/1NKbGlp Connect with me My Blog: https://mindyourdecisions.com/blog/ Twitter: https://twitter.com/preshtalwalkar Newsletter (sent only for big news, like a new book release): http://eepurl.com/KvS0r 2017 Shorty Awards Nominee. Mind Your Decisions was nominated in the STEM category (Science, Technology, Engineering, and Math) along with eventual winner Bill Nye; finalists Adam Savage, Dr. Sandra Lee, Simone Giertz, Tim Peake, Unbox Therapy; and other nominees Elon Musk, Gizmoslip, Hope Jahren, Life Noggin, and Nerdwriter.