Question:
A bag contains 6 red, 8 black and 4 white balls. A ball is drawn at random. What is the probability that ball drawn is not black?
Solution:
Number of red balls $=6$
Number of black balls $=8$
Number of white balls $=4$
Total number of balls $=6+8+4=18$
$\therefore$ Total number of cases $=18$
Again, number of balls that are not black $=18-8=10$
Thus, the number of favourable cases is 10 .
$\therefore P($ the drawn ball is not black $)=\frac{\text { Number of favourable cases }}{\text { Total number cases }}=\frac{10}{18}=\frac{5}{9}$