Respuesta :
Answer:
The competition can be played in 7 different ways
Step-by-step explanation:
First game : X
Second game : Y
Third game : Y
After that either X or Y can win
¹Case - 1: Y wins the fourth game:
The competition ends with Y winning as he/she won 3 games in a row
Case - 2: X wins the fourth game:
more games are required to decide the winner
Sub-case - a: X wins the fifth game:
more games are required to decide the winner
²Sub-sub-case - i: X wins the sixth game:
The competition ends with X winning as he/she won 3 games in a row
³⁻⁴Sub-sub-case - ii: Y wins the sixth game:
The competition ends after the seventh game. Whoever wins seventh game wins the competition as he/she would've won 4 games in total by then.
Sub-case - b: Y wins the fifth game:
more games are required to decide the winner
⁵Sub-sub-case - i: Y wins the sixth game:
The competition ends with Y winning as he/she won 4 games in total
⁶⁻⁷Sub-sub-case - ii: X wins the sixth game:
The competition ends after the seventh game. Whoever wins seventh game wins the competition as he/she would've won 4 games in total by then.
∴The competition can be played in 7 different ways
