# Volleyball Probability

**Discrete Mathematics**Level 4

Two equally matched teams are playing a game of volleyball. Each team has a \(\frac{1}{2}\) chance of winning each point. The game ends once one of the teams gets to a score of 21. If the score is currently 18-16 for team A, the probability that team A will win the game can be expressed as \(\frac{a}{b}\) where \(a\) and \(b\) are coprime positive integers. What is the value of \(a + b\)?

**Details and assumptions**

Clarification: Team A currently has 18 points, expressed via "18-16 for team A".