Decide if it's permuatation or combination .

1-how many teams of 4 horses be made if there were 9 horses in total ?
2-mike has nice baseball trophies to arrange on the shelf . How many different ways can be arranged ?
3-in a math class , there are 24 students,the teacher picks 4 students to help do a demonstration.how many diffrent groups of 4 could she have chosen ?

1 answer

if order matters, it's permutations
if not, then it's combinations