Question

A bag contains 5 black, 7 red and 3 white balls. A ball is drawn from the bag at random. Find the probability that the ball drawn is:

(i) Red

(ii) Black or White

(iii) Not black

Answer 1

Total no. of possible outcomes = 15

{5 black, 7 red & 3 white balls}

(i) E ⟶ event of drawing red ball

No. of favorable outcomes = 7 {7 red balls}

Probability, P(E) = (No.of favorable outcomes)/(Total no.of possible outcomes)

P(E) = 7/15

(ii) E ⟶ event of drawing black or white

No. of favourable outcomes = 8 {5 black & 3 white}

P(E) = 8/15

(iii) E ⟶ event of drawing black ball

No. of favourable outcomes = 5 {5 black balls}

P (E) = 5/15 = 1/3

Bar E⟶event of not drawing black ball

P (Bar E)=1−P(E)

= 1 − 1/3 = 2/3