There are two bags, the first bag contains 2 white balls and 5 black balls and the second contains 3 white balls and 4 black balls. What is the probability that the first bag was chosen given a white ball was chosen? Now suppose the ball was put back into its original bag, and another ball is picked from the same bag randomly. What is the probability that the second ball is also white?
For the first question I got 2/7 by doing probability of the first bag and a red ball being chosen divided by the probability of the first bag being chosen. ((1/2)*(2/7))/(1/2). (Don't know if this is right)
I'm not sure how to go about doing the second part.