There are 10 coins that look exactly the same: One of the coins is fair (meaning that the probability of heads is 1/2 and the probability of tails is 1/2). Nine of the coins are biased such that the probability of heads is 2/3 and the probability of tails is 1/3. Suppose your friend selects one of the coins uniformly at random. Your friend flips the coin 10 times and tells you that it came up H 5 times and T 5 times. Based on this information, what is the probability that your friend selected the fair coin?