Please answer all and show the steps for understanding, thank you so much!

1. The BMCC math club has 50 members. a. In how many different ways can it select a group of 4 members? b. In how many different ways can it elect a president, vice-president, secretary and treasurer? One member CANNOT hold more than one job. 2. In a race in which 10 cars are entered and there are not ties, in how many ways can the first three finishers come in? 3. There are 8 different cell phones in total. a. You want to buy two cell phones. In how many ways can a group of two cell phones be selected? b. You want to buy two cell phones. One cell phone is for your mom and the other one is for your dad. How many different ways are there? 4. Suppose you are asked to choose three movies. If there are 20 different movies, in how many ways can the three movies be chosen