A math problem for help; The NBA adopts the best of seven games system. In other words, if a team wins four games first, the game is over. The Lakers and the Rockets won every game.

The reason is: If K matches are over, one of the two teams is required to win three games in the first k- 1 match. At this time, the discussion will be classified: either the Rockets or the Lakers. If the rocket wins three games first, the probability is CK-1\ 3 (1/2) k-1,and then there is another game. The rocket must win this game, and the probability is 1/2. So if it's field K and the Rockets win, the probability is CK-1\ 3 (1/2) k-1×1/2. Similarly, if the Lakers win, the probability is the same. Add the two together and you will get the answer.

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