There are 5 green, 6 black and 7 white balls in a bag. A ball is drawn at random from the bag. Find the probability that it is not white.
Number of green balls = 5
Number of black balls = 6
Number of white balls = 7
Total number of outcomes = 5 + 6 + 7 = 18
There are 18 balls out of which 11 are not white.
⇒ Number of favourable outcomes = 11
Probability of an event, P(E)=Number of favourable outcomesTotal number of outcomes
⇒ P( ball drawn is not white) = 1118
∴ Probability that the ball drawn is not white is 1118 .
P (ball drawn is white) = 718
By complementary event formula,
P( ball drawn is white) + P( ball drawn is not white) = 1
⇒ P( ball drawn is not white)
=1−P( ball drawn is white)
∴ Probability that the ball drawn is not white is 1118.