Days ago, Czech kids who are 14-15 years old were trying to pass their high school entry exams designed by CERMAT, a centralized institution producing exams for schools. The most difficult problem was an exercise involving a tractor and a tube of paint in mathematics.
This El Risitas parody got over 100,000 views. El Risitas' German counterpart, Adolf Hitler, was just a little bit less successful.

Zetor Major
The problem is the following:
A tractor ran over a tube of paint. The tube exploded, paint was all around, and the tractor was leaving a mark on the road every 252 centimeters. What is the height of the center of the contaminated tractor's wheel?
Many people who follow the education of mathematics agreed that it was an easy enough, well-chosen, yet "somewhat nontrivial" problem that the good enough kids really should be able to solve. Just to be sure, the solution is \(252\,{\rm cm} / 2\pi \approx 40.16\,{\rm cm}\).
Tons of kids whined and claimed that it was harder than a year ago – and it was like a problem in an entry exam for a university. Oh, really?