Example 16 Bag I contains 3 red and 4 black balls while another Bag II contains 5 red
and 6 black balls One ball is drawn at random from one of the bags and it is found to
be red Find the probability that it was drawn from Bag II Solution Let E1 be the event of choosing the bag I, E2 the event of choosing the bag II
and A be the event of drawing a red ball