10 people come to play basketball. How many ways there are: a. To choose 2 teams of 5 players? (remember about duplicates) 126 b. To choose 2 teams if we know that Jack and Hannah should be in one team? 107 c. To choose 2 teams if two tallest people should be in different teams? 107 d. To choose a team of 5 if we want to assign roles: 2 forwards, center, and 2 guards? 5*3*1 = 15

Am I right?