what is the key relationship? fully explain please

Slim-Down Manufacturing makes a line of nutritionally complete, weight-reduction beverages. One of their products is a strawberry shake which is designed to be a complete meal. The strawberry shake consists of several ingredients. Some information about each of these ingredients is given below. Calories Total Vitamin from Fat Calories Content Thickeners Cost (per (per (mg/ (mg/ tbsp) tbsp) tbsp) tbsp) tbsp) 1 75 50 100 20 0 3 8 10 8 Ingredient Strawberry flavoring Cream Vitamin supplement Artificial sweetener Thickening agent 0 0 50 1 25 0 120 0 2 15 30 80 2 25 6 The nutritional requirements are as follows. The beverage must total between 380 and 420 calories (inclusive). No more than 20 percent of the total calories should come from fat. There must be at least 50 milligrams (mg) of vitamin content. For taste reasons, there must be at least 2 tablespoons (tbsp) of strawberry flavoring for each tablespoon of artificial sweetener. Finally, to maintain proper thickness, there must be exactly 15 mg of thickeners in the beverage. Management would like to select the quantity of each ingredient for the beverage which would minimize cost while meeting the above requirements