Answer and explanation:
The gambler's fallacy is the fallacy of belief that if an event such as a loss occurs more frequently in the past, it is less likely to happen in the future. We assume here that this belief is true, therefore
If she loses, her probability of winning increases =3/4
If she wins, her probability to win is normal =1/2
Given that probability of winning is 1/2
Probability of losing is 1-1/2=1/2
Probability that she wins the tournament is probability that she wins the first two games and loses the last or wins the first game, loses the second and wins the last or loses the first game and wins the last two games or probability that she wins all three games
=1/2*1/2*1/2+1/2*1/2*3/4+1/2*3/4*1/2+1/2*1/2*1/2
=25/48
Probability of winning the tournament if she loses the first game
=1/2*3/4*1/2= 3/16
Note: whenever there is "or" in probability, you add