there are 'n' urns numbered through 1 to n. The i^th urn contains i white and (n+1-i) black marbles. Let Ei denote the event of selecting i^th urn and let W denote the event that the marble drawn from the selected urn is white. Now, if n is an even integer and if P(Ei)=1/n for every i, and E denotes the event of choosing even numbered urn then P(W|E) is?
