JEE Advance - Mathematics (2006 - No. 8)
Let $$P\left( {{u_i}} \right) = {1 \over n},$$ if $$n$$ is even and $$E$$ denotes the event of choosing even numbered urn, then the value of $$P\left( {w/E} \right)$$ is
$${{n + 2} \over {2n + 1}}$$
$${{n + 2} \over {2\left( {n + 1} \right)}}$$
$${n \over {n + 1}}$$
$${1 \over {n + 1}}$$