Diet Problem

My diet requires that all the food I eat come from one of the four "basic food groups" (chocolate cake, ice cream, soda and cheesecake). At present, the following four foods are available for consumption: brownies, chocolate ice cream, cola and pineapple cheesecake. Each brownie costs 50¢, each scoop of chocolate ice cream costs 20¢, each bottle of cola costs 30¢ and each piece of pineapple cheesecake costs 80¢. Each day, I must ingest at least 500 calories, 6 oz of chocolate, 10 oz of sugar and 8 oz of fat. The nutritional content per unit of each food is:
  Calories Chocolate (ounces) Sugar (ounces) Fat (ounces)
Brownie 400 3 2 2
Chocolate ice cream (1 scoop) 200 2 2 4
Cola (1 bottle) 150 0 4 1
Pineapple cheesecake (1 piece) 500 0 4 5

Formulate a linear programming model that can be used to satisfy my daily nutritional requirements at minimum cost.