You have two biased coins. Coin A comes up heads with probability 1/4. Coin B comes up heads with probability 3/4. However, you are not sure which is which so you flip each coin once, choosing the first coin randomly. Use Hi and Ti to denote the result of flip i. Let A1 be the event that coin A was flipped first. Let B1 be the event that coin B was flipped first. What is P[H1 H2]? Are H1 and H2 independent? Explain your answer.