25 horses, a five-lane track and no stopwatch: find the fastest three in as few races as possible.

Twenty-five horses, a track that takes five at a time, and no stopwatch. The story runs the five heats and the race of group winners, then asks for the minimum number of races to find the fastest three. You type your answer and check it. Then you step through the answer and the breakdown.

Why quant interviews test this

Interviewers want the elimination argument and the reason six races cannot be enough. The written solution is at /brain-teasers/twenty-five-horses/solution.

The Twenty-Five Horses guide covers how scoring works, the strategy that wins, a worked example and the mistakes most players make.

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