Title is misleading, the problem had already been solved. Its a good story but please don't linkbait.
Why is it important to mention that he is an Iraqi immigrant?
People who immigrate from poor countries to rich countries at the age of 10 face additional educational difficulties that most people on this board haven't. Solving a 300 year old puzzle is impressive, but it makes it even more impressive that this kid was able to do it just six years after moving to a different country and having to learn two more languages during that time, too.
my understanding is that the student simply did nontrivial work on a problem that has previously been solved, but is impressive for a high school student
Sounds like more of a story about how Swedish high school teachers are just as "well versed" in knowledge as their American counter-parts... :P