When I was in school, 50% was still a failing grade.
Funny story about grading - when I was in college as an undergrad Physics major, I signed up for the required course in Thermodynamics. This was considered to be a make or break class for Physics undergrads, much like PCHEM was for chemistry majors.
I guess I lucked out - a very senior professor was assigned to teach this course - and he didn't like it. So on the 1st day of class, he announced everyone had a "C" grade - even if they did no work and never showed. If you handed in the midterm take-home exam (which would NOT be graded!) you got a B. If you also handed in the take-home final, you got an A. And all the problems were from the student supplementary guide - which also included solutions.
I got an "A" of course, with almost everyone else in the class. One lone dummy settled for a C.
Funny thing is - luckily, I never needed what was supposed to be taught in that class. (The next year's class wasn't so lucky.)