The Raptors are playing a best of 7 final series against the Golden State Warriors, where a team must win 4 games to win the series. Suppose the probability of the Raptors winning a game is 2/3 and the probability of the Golden State Warriors winning a game is 1/3. Suppose the Raptors won the first game; what is the probability the Golden State Warriors get their 4th win on the 7th game of the series?