1. First, figure out how many packs of cups you need. There are 60 people, and 24 cups in a package. You can't get half of a package, and you can't leave any people out.
24 * 1 = 24
24 * 2 = 48
24 * 3 = 72
2. Now that you know that you need to buy 3 packages of cups, you need to figure out how many packages of napkins you need. There are 60 people and 18 napkins in a package.
18 * 1 = 18
18 * 2 = 36
18 * 3 = 54
18 * 4 = 72
3. Now you know that you need to buy 3 packages of cups and 4 packages of napkins in order for all 60 guests to be able to have at least one cup and one napkin.
