JEE Advance - Mathematics (2001 - No. 6)
An urn contains $$m$$ white and $$n$$ black balls. A ball is drawn at random and is put back into the urn along with $$k$$ additional balls of the same colour as that of the ball drawn. A ball is again drawn at random. What is the probability that the ball drawn now is white?
$$\frac{m}{m+n}$$
$$\frac{n}{m+n}$$
$$\frac{m+k}{m+n+k}$$
$$\frac{n+k}{m+n+k}$$
$$\frac{k}{m+n}$$