HELP ME PLESE ,3 I NEED THIS

Which equation expression the relationship between the number of boxes b and the number of cans c and the proportion is 48

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?

I’m really confused and need your assist me with this question i’ve never been taught