Brain Teasers
Madadian Race Horses
Mad Ade's rich uncle "Uncle Rich" owned the famous Madadian Race horse breeding stables "The Gluepot".
It has a private race track that has five lanes.
Uncle Rich has 25 horses and wishes to know which are the three fastest.
What is the least number of races needed to be run to find the answer?
Note that it is only the ranking of the horses being found not the actual timings.
It has a private race track that has five lanes.
Uncle Rich has 25 horses and wishes to know which are the three fastest.
What is the least number of races needed to be run to find the answer?
Note that it is only the ranking of the horses being found not the actual timings.
Answer
Answer: 7 racesRace #1 to Race #5 - Divide the horses into 5 groups of 5. Race each group to rank the first 3 in each - that's 5 races.
Race #6 - Race the winner from each group. The winner in this race is the fastest horse.
Race #7 - Race the second and third horses from the race in which the fastest horse raced initially,
the first and second horses from the group of the second horse in Race #6, and the third horse in Race #6 (that's a total of 5 horses).
The first and second horses in Race #7 are the second and third horses of the entire stable.
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