Question:
A bag contains 3 red balls and 5 black balls. A ball is drawn at random from the bag. What is the probability that the ball drawn is:
(i) red
(ii) black
Solution:
Number of red balls $=3$
Number of black balls $=5$
Total number of balls $=3+5=8$
(i) Let $A$ be the event of drawing a red ball.
$\therefore P(A)=\frac{\text { Number of favourable outcomes }}{\text { Total number of outcomes }}=\frac{3}{8}$
(ii) Let $\mathrm{B}$ be the event of drawing a black ball.
$\therefore P(B)=\frac{\text { Number of favourable outcomes }}{\text { Total number of outcomes }}=\frac{5}{8}$