Question: There are two ums. The first urn contains 2 black bails and 3 white balls. The second urn contains 4 black balls and 3 white balls. An urn is chosen at random, and a ball is chosen random from that urn.

a) Draw a suitable tree diagram,

b) Assign probabilities and conditional probabilities to the branches of the tree.

c) Calculate the probability that the ball drawn is black.