An urn contains 12 balls: 5 red, 4 white, and 3 blue. A trial consists of selecting one ball from the urn and replacing the ball.

Question

An urn contains 12 balls: 5 red, 4 white, and 3 blue. A trial consists of selecting one ball from the urn and replacing the ball. Compute the probability that in 3 trials all three balls are different in color.

Answer 1

Say the order of different colors is rwb, the probability for that would be 5/12 * 4/12 * 3/12 = 5/144

Now you have 3! permutations of r, w and b, hence hence the overall probability will be, 6*5/144