There are three boxes with balls. The first box is yellow, second box is green, and third box is white. Thre are 7 red and 12 blue balls in yellow box, 3 red and 6 blue balls in green box, and 11 red and 6 blue balls in white box. First box is selected at random, and then from the selected box a ball is selected at random.
(a) If selected box is tellow determine the probability that the selected ball is blue.
(b) If selected ball is red determine the probability that it was selected from the yellow box.
(c) If selected ball is blue find the probability that it was chosen from the white box.