# Have a bite...

Suppose Finn and Sharky are playing a match of games in which they have respective probabilities of $$\dfrac{4}{7}$$ and $$\dfrac{3}{7}$$ of winning any single game, (no ties are possible).

The match ends when one of the players wins two consecutive games. The probability that Finn wins the match is $$\dfrac{a}{b}$$, where $$a$$ and $$b$$ are positive coprime integers.

Find $$b - a$$.

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