Dividir 8a2+12ab-4b2 entre b-a

Jackie bought a bag of oranges. she used 3/8 of the oranges to make orange juice. she used 1/3 of the oranges to make a fruit salad. she put 1/8 of the oranges in a bowl on the table. she put 2/12 of the oranges in the refrigerator. a) jackie left more oranges on the table than she put in the refrigerator. b) jackie used fewer oranges to make orange juice than she left on the table. c) jackie put fewer oranges in the refrigerator than she used to make the fruit salad. eliminate d) jackie used more oranges to make a fruit salad than she used to make orange juice.

Need on this one asap im almost done with this subject

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?