Twenty-five horses, five lanes, the top two
You have 25 horses and a track with 5 lanes, so each race compares 5 horses. There is no stopwatch; a race tells you only the finishing order. Each horse always runs at the same speed.
- How many races are needed to find the single fastest horse?
- How many to find the fastest two, in order?
(The classic version asks for the top three and needs 7.)
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Five heats sort the horses into groups. One more race among the heat winners finds the champion. Then ask which horses could still be second.
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