Q. 16 Bag I contains 3 red and 4 black balls and Bag II contains 4 red and 5 black balls. One ball is transferred from Bag I to Bag II and then a ball is drawn from Bag II. The ball so drawn is found to be red in colour. Find the probability that the transferred ball is black.
Let E1 and E2 respectively denote the event that red ball is transferred from bag 1 to bag 2 and a black ball is transferred from bag 1 to bag2.
and
Let A be the event that ball drawn is red.
When a red ball is transferred from bag 1 to bag 2.
When a black ball is transferred from bag 1 to bag 2.