That’s outrageous!
I presume that you were referring to a passing grade of 40% in Algebra. Then, you should have seen the text books, absolutely no examples given. So, if a student didn’t get the lesson in class, there was no hope of taking it home and studying the example until you they understood it, or even getting help from a parent, who would need to review the example before explaining it.
Tests were all scantron, so there was no learning by reviewing the mistakes on the tests, either. Even Geometry tests were scantron, multiple choice tests.