If A and B are two events such that 2P(A) = 3P(B), where 0 < P(A) < P(B) < 1, then which one of the following is correct?

A box has ten chits numbered 0, 1, 2, 3, ......., 9. First, one chit is drawn at random and kept aside. From the remaining, a second chit is drawn at random. What is the probability that the second chit drawn is "9" ?

One bag contains 3 white and 2 black balls, another bag contains 5 white and 3 black balls. If a bag is chosen at random and a ball is drawn from it, what is the chance that it is white?

Consider the following in respect to two events A and B

I. P(A occurs but not B) = P(A) $$-$$ P(B) if B $$ \subset $$ A

II. P(A alone or B alone occurs) = P(A) + P(B) $$-$$ P(A $$\cap$$ B)

III. P(A $$\cup$$ B) = P(A) + P(B) if A and B are mutually exclusive

Which of the above is/are correct?