As someone who attended the IMO, I can tell you it varies widely. For some people, they screw around a lot, attend math camp but spend a lot of time playing gam

As someone who attended the IMO, I can tell you it varies widely. For some people, they screw around a lot, attend math camp but spend a lot of time playing games, dick around doing normal teenager things, get in trouble for stupid teenager things, don't study too hard, and nevertheless do well enough to attend the IMO. And then some people are responsible, study a lot, work hard, keep their heads down, and also attend the IMO.