Indicate whether the problem involves permutations or combinations. It is not necessary to solve the problem. 1. A medical researcher needs 6 people to test the effectiveness of an experimental drug. If 13 people have volunteered for the test, in how many ways can 6 people be selected? 2. Fifty people purchase raffle tickets. Three winning tickets are selected at random. If first prize is $1000, second prize is $500, and third prize is $100, in how many different ways can the prizes be awarded? 3. Fifty people purchase raffl e tickets. Three winning tickets are selected at random. If each prize is $500, in how many different ways can the prizes be awarded? A popular brand of pen is available in three colors (red, green, or blue) and four writing tips (bold, medium, fine, or micro). How many different choices of pens do you have with this brand? An ice cream store sells two drinks (sodas or milk shakes), in four sizes (small, medium, large, or jumbo), and fi ve fl avors (vanilla, strawberry, chocolate, coffee, or pistachio). In how many ways can a customer order a drink? How many different four-letter radio station call letters can be formed if the first letter must be W or K? Calculate: 1.9P4 2. 8P5 3.6P6 Calculate: 1.9C5 2. 11C4 3.7C7