Crudely, IMO gold medals are awarded to the highest-scoring 1/12 of contestants.1 However, because scores are integers up to 42 and there’s no provision for tiebreaking, it’s possible for a lot of contestants to be tied around the threshold. In that case, either all of them get a gold medal or none do, and the fraction of gold medalists might deviate substantially from 1/12. That’s what happened this year: 46 contestants all won a gold medal by scoring exactly 35 points.

In fact, bizarrely, 35 is the mode of the scores this year; the last time the modal score was a gold medal score was in 1994. And, of course, 35 is the same score claimed by AI systems from Google, OpenAI, and others."

From https://blog.vero.site/post/imo-2025