# Heads or Tails

**Discrete Mathematics**Level 3

Ali and Qasim play a game. In this game, a fair coin is tossed for a sequence of 50 times. Each time a head comes up Ali wins 1 Rupee from Qasim and each time a tail comes up Ali loses 1 Rupee to Qasim.

For example, if they had tossed the coin 5 times and the course of the game was like HTTHT then in this game Ali would have lost 1 rupee to Qasim.

The probability that Ali will win 20 rupees from Qasim is approximately \(A \times 10^{-B} \), where \(A\) and \(B\) are positive integers with \(A\) is a single-digit. Give \(A + B\) as your answer.