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2017 AIME II Question 2

AIME · 2017 AIME II

Question 2

Teams $T_1,$ $T_2,$ $T_3,$ and $T_4$ are in the playoffs. In the semifinal matches, $T_1$ plays $T_4,$ and $T_2$ plays $T_3.$ The winners of those two matches will play each other in the final match to determine the champion. When $T_i$ plays $T_j,$ the probability that $T_i$ wins is $\frac{i}{i+j},$ and the outcomes of all the matches are independent. The probability that $T_4$ will be the champion is $\frac{p}{q},$ where $p$ and $q$ are relatively prime positive integers. Find $p + q.$