Solution:
Total number of balls = 3 + 5 + 2 = 10
So, the total number of possible outcomes = 10
(i) There are 5 black balls
So, the number of favourable outcomes = 5
Thus, P(getting a black ball) = 5/10 = 1/2
(ii) There are 2 red balls
So, the number of favourable outcomes = 2
Thus, P(getting a red ball) = 2/10 = 1/5