A baker prepares a cake mix that weighs 120 pounds. The cake mix
consists of shortening and other ingredients. The weights of the other ingredients are, 20 1/2 pounds of flour, 29 3/4 pounds of sugar, 18 1/8 pounds of milk, 16 pounds of whole eggs, and a total of 5 1/4 pounds of flavoring, salt, and baking powder. How many pounds of shortening are used in this cake mix?