Answer the questions below. (If necessary, consult a list of formulas.) (a) There are 17 appetizers available at a restaurant. From these, Teresa is to choose 12 for her party. How many groups of 12 appetizers are possible? [I] (b) There are 13 European cities that Teresa would eventually like to visit. On her next vacation, though, she only has time to visit 3 of the cities: one on Monday, one on Tuesday, and one on Wednesday. She is now trying to make a schedule of which city she'll visit on which day. How many different schedules are possible? (Assume that she will not visit a city more than once.) [i