I'm taking a combinatorics course this semester (from the math department), and my professor said the exams are usually devised so that the average score is a 60%, and then they're curved. I've seen this method of exam development with other professors, so I wanted to get some input to help understand the reasoning behind this. I'm not disappointed or upset; I'm actually looking forward to the challenge. This is pure curiosity. Venturing a guess, it might be a way to identify potential research assistant candidates. The professor for my course does research in linear programming and combinatorics. Not sure if this should go in the Educators subform or not.