I've recently found an extended version of a rather well-known question.
The question goes as follows:
'There are 37 racehorses. You can race them together 6 at a time, and observe their relative performance. You do not have a timer. How many races do you need to determine the three fastest horses?'
Here is the link to the solution of the standard version of the puzzle.
https://puzzling.stackexchange.com/questions/51754/25-horses-find-the-3-fastest-ones
Going by the above solution, it seems to me that the answer to the 37 horses version is 8. Is that correct?