MATHEMATICS · Multi-part · CBSE · Mathematics · Permutations and Combinations · Permutations and Combinations
Problem
A box contains 3 black, 4 white and 5 red balls that are identical in all respects except colour. Two balls are drawn simultaneously at random. Answer the following questions:
(i) Determine the total number of unordered pairs of balls that can be drawn.
(ii) Calculate the probability that both balls drawn are of the same colour.
(iii) Calculate the probability that the two balls drawn are of different colours.
(iv) Calculate the probability that at least one of the two balls drawn is red.