A box contains a certain number of balls out of which 15% are red, 80% are yellow and 5% are green. All the balls of the same color are indistinguishable. Further, it is known that among all the yellow balls, x% are defective, among all the red, 6% are marked defective and among all the green balls, 9% are marked defective. A ball is chosen at random. If the conditional probability that the chosen ball is yellow, given