Question

A bag contains 3 red balls, 5 black balls and 4 white balls. A ball is drawn at random from the bag. What is the probability that the ball drawn is :
(a)white?
(b)red?
(c)black?
(d)not red?

Answer 1

SOLUTION :  

GIVEN : Number of red balls = 3

Number of white balls = 4

Number of black balls = 5

Total number of balls in a bag  = 3 + 4 + 5 = 12

Total number of outcomes = 12

(a) Let E1 = Event  of selecting a white ball  

Number of outcome favourable to E 1 = 4

Probability (E1) = Number of favourable outcomes / Total number of outcomes

P(E1) = 4/12 = 1/3

Hence, the required probability of getting a white ball , P(E1) = ⅓ .

(b) Let E2 = Event of selecting a red ball  

Number of outcome favourable to E2 = 3

Probability (E2) = Number of favourable outcomes / Total number of outcomes

P(E2) = 3/12 = 1/4

Hence, the required probability of getting a red ball , P(E2) = ¼ .

(C)Let E3 = Event  of selecting a black ball  

Number of outcome favourable to E3 = 5

Probability (E3) = Number of favourable outcomes / Total number of outcomes

P(E3) = 5/12  

Hence, the required probability of getting a black ball , P(E3) = 5/12 .

(d) Let E4 = Event  of selecting not a red ball

Total number of non red balls =  4 + 5 = 9  

Number of outcome favourable to E = 9

Probability (E4) = Number of favourable outcomes / Total number of outcomes

P(E4) = 9/12 = 3/4

Hence, the required probability of getting not a red ball , P(E4) = 3/4 .

HOPE THIS ANSWER WILL HELP  YOU….

Answer 2

Total no. of balls in a bag = 12
(a). No. of white balls in a bag = 4
P(E getting a white ball) = 4/12 = ⅓

(b). No. of red balls in a bag = 3
P (E getting a red ball) = 3/12 = ¼

(c). No.of black balls in a bag = 5
P(E fetting a black ball) = 5/12

(d). No. of not red balls in a bag = 5+4 =9
P(E getting not a red ball) = 9/12 = 3/4