[saucerful]

These were for university. This sort of addresses your point:

Now, after thirty years, these problems seem easier. Mostly, this is because the ideas of how to solve these problems have spread and are now a part of the standard set of ideas. Thirty years ago these problems were harder to solve and, in addition, the students were given these problems one after another until they failed one of them, at which point they were given a failing mark.

[adgar]

I agree that the problems have gotten much simpler - several of these remind me a lot of the difficulty I saw on the AIME back in 10th-12th grade. I mean, that's still pretty advanced relatively speaking, but certainly doable by tens of thousands of high school aged students each year.

And then there's two levels of competition past that I never made it to... just 1... damn... question... short...

[cperciva]

And then there's two levels of competition past that I never made it to... just 1... damn... question... short...

I got a perfect score on the AIME in 1998, but they didn't let Canadians write the USAMO back then. :-(