Hello my day has been terrible so please help me with my math

Astudent received the following grades last semester. find the student's semester grade point average. an a is algebra (3 credits), a b in history ( 3 credits), a in sociology ( 3 credits) a d in english ( 3credits) and a c in seminar ( 2credits). an a is worth 4 points, a b is worth 3 points a c is worth 2 points and a d is worth 1 point.

Negative 5 1/12 + negative 4 1/4 + 6 3/4

There are three bags: a (contains 2 white and 4 red balls), b (8 white, 4 red) and c (1 white 3 red). you select one ball at random from each bag, observe that exactly two are white, but forget which ball came from which bag. what is the probability that you selected a white ball from bag a?