A box contains 3 blue, 2 white and 4 red marbles. If a marbles is drawn at random from the box, what is the probability that it will not be a white marble?
Total numbers of elementary events are: 3 + 2 + 4 = 9
Let E be the event of not white ball drawn
Numbers of non-favourable outcomes = numbers of white ball drawn = 2
P (white ball) = 2/9
P (E) = 1- 2/9 = 7/9