1. 20 people go to a movie theater, and have a chance to win a $100 gift card, $50 gift card, 2 tickets, or a free popcorn. How many ways can the prizes be awarded?

2. Five couples go to the baseball game. How can the seats be arranged if each couple wants to sit together and the order within each couple does not matter?

3. A man's wallet contains 4 twenties, 3 fifties, and 3 tens. What is the probability that his son will randomly take out a twenty, given that he already took out a ten?

4. Pizza Hut has 10 toppings for pizza. How many ways can someone chose 3 toppings for one pizza?