Question

A bag contains 4 blue marbles, 5 red marbles and 3 green marbles. Two marbles are
picked at random from the bag, without replacement. Work out the probability that the
two marbles are either both blue or both green.

Answer 1

Answer:

Let Blue Marbles be B.

Red Marbles be R

Green marbles be G

Sample Space (S) = {B1, B2, B3 , B4, R1, R2, R3, R4, R5, G1, G2 , G3}

n(S) = 12

Event A : To get either both blue or both green marbles.

(A) = {BB , GG}

n(A) = 2

$\therefore P(A) = \frac{2}{12}$

$\therefore P(A) = \frac{1}{6}$