Player could win 6 games out of 10 on average. Playing one game will cost 10 minutes.Suppose The winning rate is the same and the time consumption for one game is the same. In the game, suppose the Player plans to use Character1 to win 25 games and use Character2 to win the rest 75 games. Let T3 be the random variable about the time spent to win the 25 games with Character1 and T4 be the random variable about the time spent to win the 75 game with Character2. If given the total time Player can use for playing games is 10 hours, what is the method we can use to find the conditional probability density function about T3?

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