The total weight of a box cannot exceed 17 pounds so far she has packed 3 1/4 pictures two books weighing 1 3/4 pounds and a jacket weighing 1 1/2 how much more can be packed without going over

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?