A bag contains 3 white, 4 red and 5 black balls. One ball is drawn at random. What is the probability that the ball is neither black nor white?


Total numbers of elementary events are: 3 + 4 + 5 = 12


Let E be the event of drawing neither black ball nor white ball


Number of outcomes of drawing a black ball or white ball = 5/ 12 + 3/12 = 8/12 = 2/3


Number of favourable outcomes are = 1-2/3 = 1/3

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