Question

Teams A and B play in a tournament. The first team to win three games wins the

tournament. Find the number n of possible ways the tournament can occur.

Answer 1

Sample space

$$S=\{AAA, AABA, AABBA, AABBB,$$

$$ABAA, ABABA, ABABB,ABBAA,$$

$$ABBAB, ABBB, BAAA,BAABA,$$

$$BAABB, BABAA, BABAB, BABB,$$

$$BBAAA, BBAAB,BBAB, BBB\}$$

$$n=20$$