Question: 15) A pastry chef who specializes in special occasion cakes uses the following multiple regression equation to help calculate the price of a cake:

where \({{x}_{1}}\) is the number of layers desired, \({{x}_{2}}\) is the number of servings needed, and \({{x}_{3}}\) is the amount of filling mix used. Calculate the price of a three-layer cake to serve 48 people using 40 ounces of filling.