HELLP!! i need help with this taking a test

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?

Simplify the given expression leaving the answer in improper fraction form. 2/3+5/6

Which of the following is another way to express the difference between -5 and 8?