let
A : Ball drawn from bag A
B : Ball is drawn from bag B
C : Ball is drawn from bag C
BB : Black ball
WB : White ball
Assuming, selecting bags is of equal probability i.e. \(\frac{1}{3}\)
We want to find P(A|W), i.e. probability of selected White ball is from bag A
Conclusion: Therefore, the probability of selected white ball is from bag A is \(\frac{2}{9}\)