Question

a bag contains 2 red, 3 green and 2 blue balls. two balls are drawn at random. what is the probability that none of the balls drawn is blue?

Answer 1

The probability of none of the balls drawn is blue = 5/7

Answer 2

Answer:

The probability that none of the balls drawn is blue is 0.476

Sum of number of balls =2 +3 +2 = 7

Assume that, S be the sample space and 'n(S)' be number of ways of drawing 2 balls out of 7 , which implies that;

n(S) = ⁷C₂ = (7*6)/ (2*1)  =21

Consider 'A' be event of drawing 2 balls, none of which is blue.

n(A) = Number of ways of drawing 2 balls out of (2+3) balls.

n(A) = ⁵C₂ = (5*4)/(2*1) = 10

P(A) = n(A)/ n(S) = 10/ 21 = 0.476