Question

A bag contains 4 white balls, 5 red balls, 8 black balls and 3 blue balls. A ball is drawn at random from the bag. Find the probability that the ball drawn is (i) red or blue (ii) not black and (iii) neither black nor red.

Answer 1

Total possible outcomes = Total number of balls

= ( 4 + 5 + 8 + 3) = 20

(i) Total number of red and blue balls = (5 + 3) = 8

∴ P (getting a red or blue ball ) = $\frac{8}{20}=\frac{2}{5}$

(ii) Total number of balls that are not of black colour = (4 + 5 + 3) = 12
∴ P (getting a ball that is not of black colour ) = $\frac{12}{20}=\frac{3}{5}$

(iii ) Total number of balls that are not black or red = (4 +3) = 7
∴ P (getting a ball that is neither black nor red) = $\frac{7}{20}$