I got a problem with probability.
Two vases are not distinguishable (V1 and V2). V1 contains 3 red, 5 white and 7 blue balls. V2 contains 7 red, 5 white and 3 blue balls.
Someone takes a ball from V1 and puts it in V2 unseen. One draws randomly a ball from V2. This ball is red. What is the probability that the ball, unseen from V1 in V2 is laid, is white?
This is what I thought: Probability = P(White ball AND V1) / P(V1) = (5/30) / (15/30).
I feel I need to do something with the red ball that is taken. But I don't know what.