Answer to Question #74951 in Statistics and Probability for Pranjal Shukla

Question

There are three urns, urn 1 having 5 white and 3 black balls, urn 2 with 4 white and 4 black balls and urn 3 with 3 white and 5 black balls. A fair die is tossed and
i) urn 1 is chosen if dice shows up 1,2 or 3,
ii) urn 2 is chosen if dice shows up 4 or 5,
iii) urn 3 is chosen if dice shows up 6.

2 balls are drawn at random from the chosen urn. What is tha probability that one of the balls drawn is white and the other black ?