Please solve part c using LINGO in explicit mode

Ralph Edmund loves steaks and potatoes. Therefore, he has decided to go on a steady diet of only these two foods (plus some liquids and vitamin supplements) for all his meals. Ralph realizes that this isn't the healthiest diet, so he wants to make sure that he eats the right quantities of the two foods to satisfy some key nutritional requirements. He has obtained the nutritional and cost information shown at the top of the next column. Ralph wishes to determine the number of daily servings (may be fractional) of steak and potatoes that will meet these requirements at a minimum cost. (c) Use a computer to solve this model by the simplex method. Grams of Ingredient per Serving Daily Requirement (Grams) Steak Potatoes Ingredient Carbohydrates Protein 5 20 15 15 5 2 50 2 40