Question

A box contains 7 red balls, 8 green balls and 5 white balls. A ball is drawn at random from the box. Find the probability that the ball is neither red nor white.

Answer 1

Total number of balls in the box = 7 + 8 + 5 = 20 balls

Total possible outcomes = 20 = n(S) 

Neither red ball nor white ball = green ball 

Event of not drawing a red or white ball = E = number of green ball

n(E) = 8 

Probability of drawing a white ball = `(n(E))/(n(S)) = 8/20 = 2/5`