[rjtobin]

There is at least one reason - it was a harder problem. Agreed that which IMO problems are hard for a human IMO participant and which are hard for an LLM are different things, but seems like they should be positively correlated at least?

[cyberax]

IMO problems are not hard. They are merely tricky. They test primarily pattern recognition capabilities, requiring that flash of insight to find the hidden clue.

So it's no wonder that AI can solve them so well. Neural networks are great at pattern recognition.

A better test is to ask the AI to come up with good Olympiad problems. I went ahead and tried, and the results are average.