Question
A bag contains 3 black balls, 7 red balls and 5 white
balls. Two balls are drawn simultaneously. Find the probability that both the balls are of same colour.Solution
Total number of balls in the bag = 3 + 7 + 5 = 15 Total possible outcomes = 15C2 = 105 Number of favourable outcomes = 3C2 + 7C2 + 5C2 = 3 + 21 + 10 = 34 Required probability = 34/105
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