Farmer Jones and Farmer Smith graze their cattle in the same field. If there are 50 cows grazing in the field, each cow produces $50,000 of milk over its lifetime. If there are more cows in the field, then each cow can eat less grass and its milk production falls. With 70 cows in the field, each produces $85000 of milk; with 100 cows, each produces $1,10,000 of milk. Cows cost $1500 each