Hi there, really struggling with these home work questions. Thanks in advance!

From a deck of 52 cards, a 5 card hand is dealt. How many distinct hands can be formed if there must be at least 2 spades?Students can choose their own groups of $ for a class project. X /EA-12 wants to randomly select his group members. If there are 16 students in a class, how many ways can X /E A-12 select his group?A researcher is studying the effects of exercise on concentration. She has 25 athlete volunteers and 15 non-athlete volunteers participating. How many groups of 8 volunteers can she make if there have to be at least 4 athletes