Number of red balls in the bag = 5
Number of white balls in the bag = 8
Number of green balls in the bag = 4
Number of black balls in the bag = 7
∴ Total number of balls in the bag = 5 + 8 + 4 + 7 = 24.
Drawing balls randomly are equally likely outcomes.
∴ Total number of possible outcomes = 24
Now,
(i) There are 7 black balls, hence the number of such favourable outcomes = 7
∴ Probability of drawing a black ball
(ii) There are 5 red balls, hence the number of such favourable outcomes = 5.
∴ Probability of drawing a red ball
∴ Probability of drawing not a red ball = P (Not Red ball) = 1 - 5/24 = 19/24
(iii) There are 4 green balls.
∴ Number of such favourable outcomes = 4
Probability of drawing a green ball