A bag contains 4 white balls, 5 red balls, 2 black balls and 4 green balls.
A ball is drawn at random from the bag. Find the probability that it is (i) black, (ii) not green, (iii) red or white, (iv) neither red nor green.
S = {4 white, 5 red, 2 black, 4 green balls}
n(s)=15
ii) Let E1 denote the event of getting a ball other than green.
n(E1)=11
P(E1)=n(E1)n(s)
P(E1)=1115
iii) Let E2 denote the event of getting a red or white ball.
n(E2)=9
P(E2)=n(E2)n(s)
P(E2)=915=35
i) Let E3 denote the event of getting a black ball.
n(E3)=2
P(E3)=n(E3)n(s)
P(E3)=215
iv) Let E4 denote the event of getting neither red nor green ball.
n(E4)=6
P(E4)=n(E4)n(s)
P(E4)=615=25