Question

a bag contains 2 white balls and 2 black balls another bag contains 4 white and 2 black one bag is selected at random what that ball chosen is white?

Answer 1

Bag 1 contain 2 white ball and two black balls
Bag 2 contain 4 white and 2 black

Probability of choosing a bag from two bags = 1/2
And probability of choosing a white ball from bag 1 =( 1/2) *(2/4) = 1/4 ( both event of choosing bag and ball are simultaneous)
And probability of choosing a white ball from bag 2 = (1/2) * (4/6) = 1/3 ( both event of choosing bag and ball are simultaneous)

Hence the probability of choosing white ball is 1/4 + 1/3 = 7/12 (ans)