Question

A ball is drawn at random from a box containing 6 red balls, 4 white balls and 5 blue balls. Determine the probability that it is (i) red (ii) white (iii) blue (iv) not red and (v) red or white.

Answer 1

$\mathcal{\pink{SOLUTION:}}$

No. of Red balls = 6
No. of White balls = 4
No. of Blue balls = 5

Total Balls = 15

A ball is drawn from 15
n(S) = 15C1 = 15

(1)
E1 - Event that ball drawn is red
n(E1) = 6C1 = 6

•°• Required probability
P(E1) = n(E1)/n(S) = 6/15

(2)
E2 - Event that ball drawn is blue
n(E2) = 5C1 = 5

•°• Required probability
P(E2) = n(E2)/n(S) = 5/15 = 1/3

(3)
E3 - Event that ball drawn is not red
Non red balls = white + blue = 4 + 5 = 9
n(E3) = 9C1

•°• Required Probability
P(E3) = n(E3)/n(S) = 9/15 = 3/5

(4)
E4 - Event that ball drawn is red OR white
=> Favourable ways of drawing = 6+4= 10
n(E4) = 10

•°• Required probability
P(E4) = n(E4)/n(S) = 10/15 = 2/3

•°•°•°•°•°<><><<><>><><>•°•°•°•°

$\mathcal{\huge{\blue{Hope it helps}}}$