Mark the correct alternative in each of the following:

An urn contains 9 balls two of which are red, three blue and four black. Three balls are drawn at random. The probability that they are of the same colour is

Mark the correct alternative in each of the following:

A bag contains 5 black balls, 4 white balls and 3 red balls. If a ball is selected random wise, the probability that it is black or red ball is

Mark the correct alternative in each of the following:

Two dice are thrown simultaneously. The probability of getting a pair of aces is

Mark the correct alternative in each of the following:

A coin is tossed three times. If events A and B are defined as A = Two heads come, B = Last should be head. Then, A and B are

Mark the correct alternative in each of the following:

Five persons entered the lift cabin on the ground floor of an 8 floor house. Suppose that each of them independently and with equal probability can leave the cabin at any floor beginning with the first, then the probability of all 5 persons leaving at different floors is