Suppose that a coin is tossed 3 times by player A, then tossed three times by player B. The coin lands heads with probability p; 0 < p < 1, and each toss is independent of the others.
a. Compute the probability that both players obtain the same number of heads.
b. Compute the probability that player A gets a head on a toss earlier than player B does (e.g., A gets a head on his second toss, but B's rst head is on his third toss).