Explanation : Probability of drawing a white ball from Box B will depend on whether transferred ball is black or white. If a black ball is transferred then its probability is 4/6 There are now 5 white and 8 black balls in the box B. Then probability of drawing white ball from the Box B = 5/13 Hence probability of drawing a white ball from urn B, if the transferred ball is black
Similarly, probability of drawing a white ball from urn E, if transferred ball is white