Question

Urn A contains 6 red & 4 black balls and urn B contains 4 red & 6 black balls. One ball is drawn at random from urn A & placed in urn B. then one ball is drawn at random from urn B & placed in urn A. If one ball is now drawn at random from urn A, then the probability that it is red is

Answer 1

when 1 ball is drawn and placed from A urn then p(a) =1/6
when again 1 ball is drawn and placed from B urn then probability will be 1/5
then at last probability will be 1/6 only.