A bag contains $5$ red, $8$ white and $7$ black balls. If A ball is drawn at random from the bag. Then Find the probability that the drawn ball is(iii) neither white nor black.

(iii) Let E be the Event of getting neither a white nor a black ball

Therefore No. of favorable outcomes $=20–8–7=5$(total balls – no. of white balls – no. of black balls)

Thus, Probability, P(E) = Number of favorable outcomes/ Total number of outcomes

P(E) $=5/20$