Question

An urn contains 5 red, 6 blue, and 8 green balls. If a set of 3 balls is randomly selected, what is the probability that each of the balls will be (a) of the same colour? (b) of different colours? Repeat under the assumption that whenever a ball is selected, its colour is noted and it is then replaced in the urn before the next selection. This is known as sampling with replacement. 

Answer 1

(a) p= ((5/3)+(6/3)+(8/3))/(19/3)

(b) p= ((5/1)(6/1)(8/1))/(19/3)