Question

An urn contains 5 red and 5 black balls. A ball is drawn at random, its colour is noted and is returned to the urn. Moreover, 2 additional balls of the colour drawn are put in the urn and then a ball is drawn at random. What is the probability that the second ball is red ? Select the correct answer from above options

Answer 1

In the first draw the ball may be red or black If red ball is drawn, 2 more red balls are put and then draw a red ball If black ball is drawn 2 more black ball is put and then again draw a red ball ∴ Required probability is