A study of laws or mathematics did never count to be anything to achieve easily at University Cologne from 1980 to 1990. For Law: The median of achievement of students participating were the barrier to have passed. For Mathematics, achieve a level of 50% of weekly written exercise, otherwise you can't take the exam. Achieve 50% of the exam to pass it. If then the amount of students, who passed, were lower than 20% the level to pass might get corrected to only need 40% of the exam, even if than still only 30% will pass the exam.

Kilde:

I can recall one exam during my studies at University of Cologne with a similar situation. You needed to pass 50% of the weekly written exercise to participate in the exam. But less then 10 % achieved the final exam. The passing level got corrected so that the amount of people passing the exam were 40%.

Kilde:

Der Besuch von Vorlesungen (Präsenzstudium!), Tutorien und nicht zuletzt der wöchentlichen Einsichten von Altklausuren führt erfahrungsgemäß zu einer ausreichenden Vorbereitung auf die Prüfung. Es steht außer Frage, dass man das Modul mit bloßem Auswendiglernen kaum bestehen wird. Wer nicht fähig ist, gewisse Transferleistungen zu erbringen, ist an einer (Fach)Hochschule u.U. nicht richtig

Kilde: habe das Modul erfolgreich absolviert