1. At a medical research center an experimental drug is to be given to 20 people, 12 children and 8 adults. If 15 children and 9 adults have volunteered to be given the drug, in how many ways can the researcher choose the 20 people to be given the drug? 2. 3 different varieties of flowers are going to be placed in a vase. There are 5 different flowers to choose from. How many combinations can be made from the 5 varieties of flowers? 3. A couple is throwing a party. They need to pick 5 different kinds of beer from the 12 beers being offered, and they need to pick 4 snacks from the 9 snacks being offered. How many different choices do they have? 4. How many groups of 3 kings and 1 jack can be made from the 4 kings and 4 jacks in a deck of cards? 5. There are 6 restaurants you would like to try on your next vacation. You only have time to try 4 of them when you go on vacation. How many groups of restaurants can you choose? 6. How many groups of 4 hearts and 2 spades can be made from the 13 hearts and 13 spades in a deck of cards? 7. In how many ways can you select a committee of 4 students out of 12 students? 8. A box contains three green balls, three yellow balls and four blue balls. In how many ways can three balls be drawn from the box, if at least one blue ball is to be included in the draw? 9. How many ways can you arrange the word RHOMBUS? 10. How many ways can you arrange 8 people in 8 chairs?