Best of Seven

Two teams, A and B, play a "Best of Seven" tournament. The first team to win four games wins the tournament. If the probability that team A will win any game is p, and the probability team B will win is (1-p),
  1. What is the probability team A (or B) will win the entire tournament?
  2. What is the expected number of games in the tournament? (If p is 0, or if p is 1, the expected number of games would be 4. When p is between 0 and 1, the expected number should rise toward 7.)

Source: Original, but I imagine it's elsewhere.

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