A professor who never had failed a student in his life just failed his whole class.
His students had argued with him in favor of social equality, spreading the wealth during a lesson, so he told them he was putting it to test.
He told his students that he would average off test scores.
First exam, the A students studied hard as usual, but they averaged B+. The B and C students averaged B
Second exam, the C students didn’t study because they knew they would average out better anyway. The B students studied as usual, and averaged out B-, the A’s B+ and the C’s C-.
Third exam, The A’s studied little, the B’s even less, and the C’s not at all. The entire class averaged C-.
Fourth exam, the entire class averaged F.