Question

A bag contains 3 red, 5 black and 7 white balls. One ball is drawn at random from the bag. What is the probability that the ball drawn is
(i) white
(ii) red
(iii) not red
(iv) red or white?

Answer 1

Total possible outcomes = Total number of balls

= ( 3 + 5 + 7) = 15

(i) Number of white balls = 7

∴ P (getting a white ball) = $\frac{7}{15}$

(ii) Number of red balls = 3
∴ P (getting a red ball) = $\frac{3}{15}=\frac{1}{5}$

(iii) Total number of non-red balls = (5 +7) = 12
∴ P (getting a non-red ball) = $\frac{12}{15}=\frac{4}{5}$

(iv) ​Total number of red or white balls = (3 +7) = 10
∴ P (getting a red or white ball) = $\frac{10}{15}=\frac{2}{3}$