Number of white balls = 4
Number of black balls = 6
Number of total balls or possible events = 6 + 4 = 10 balls
(i) Probability (a black ball)
Number of black balls = 6
Number of total balls = 10
∴ Probability = 6/10 = 3/5
(ii) P (a white ball)
Number of white balls = 4
Number of total balls = 10
∴ Probability = 4/10 = 2/5
(iii) P (not a black ball)
= number of white balls/Number of total balls = 4/10 = 2/5