this is a problem in my statistics class, and I am lost to me, it is confusing or missing something here is the problem please help

Question

grade points are assignede as follows: a=4,b=3,c=2,d=1,f=0. grades are weighted according to credit hours. if a student receives an A in a four-unit class, a d in a two-unit class, a b in a three-unit class and a C in a three-unit class, what is the students grade point average