Question

A bag contains 5 white balls, 7 red balls, 4 black balls and 2 blue balls. One ball is drawn at ran dom from the bag. What is the probability that the ball drawn is (a) white or blue, (b) not white, (c) neither white nor black?

Answer 1

Total possible outcomes = Total number of balls

= ( 5 + 7 + 4 + 2) = 18

(a) Total number of white and blue balls = (5 + 2) = 7

∴ P (getting a white or blue ball ) = $\frac{7}{18}$

(b) Total number of balls that are not of white colour = (7 + 4 + 2) = 13
∴ P (getting a ball that is not of white colour ) = $\frac{13}{18}$

(c ) Total number of balls that are neither white nor black = (7 + 2) = 9
∴ P (getting a ball that is neither white nor black) = $\frac{9}{18}=\frac{1}{2}$