A company tries to construct a diet for its workers containing at least 20 grams of protein, 25 grams of carbohydrates, 10 grams of fat and 40 units of vitamins. Give a linear programming formulation whose solution would give the cheapest way to do this, given the prices and content of the foods shown below.

	1 lb of soya meat	1 lb of dried fish	1 lb of fruit	1 gallon of milk
Protein (g)	11	7	2	4
Carbohydrates (g)	0	0	2	2
Fat (g)	6	3	2	0
Vitamins (units)	1	5	7	2
Cost (cents/amount)	25	30	20	13