Baking Cookies

Riddle: Mary is baking chocolate chip cookies for, her friend, Molly's birthday party. Molly will have 19 friends at the party plus herself. Each batch of cookies can make 24 cookies and requires: 1 cup butter, softened 1 cup white sugar 1 cup packed brown sugar 2 eggs 2 teaspoons vanilla extract 1 teaspoon baking soda 2 teaspoons hot water ½ teaspoon salt 3 cups all-purpose flour 2 cups semisweet chocolate chips 1 cup chopped walnuts Mary has: 9 cups butter 18 cups white sugar 7 cups packed brown sugar 48 eggs 12 teaspoons vanilla extract 8 teaspoons baking soda 1-gallon hot water 9 tablespoons salt 5 cups all-purpose flour 15 cups semisweet chocolate chips 5 cups chopped walnuts How many batches of cookies can Mary make? How many cookies can each friend have if they each have the same number of cookies? Will there be any cookies leftover?