If A and B are two independent events such that $$P(A) = {1 \over 2}$$ and $$P(B) = {1 \over 5}$$, then which of the following is correct?

Box I contains 5 red and 2 blue balls, while box II contains 2 red and 6 blue balls. A fair coin is tossed. If it turns up head, a ball is drawn from box I, else a ball is drawn from box II. The probability ball drawn is from box I, if it is blue, is