Haley is responsible for buying a week's supply of food and medication for the pigs and cows at a local co-op. The food and medi each cow costs four times as much as those supplies for a pig. She needs to feed 20 cows and 10 pigs. Her budget is $990. Let represent the cost per pig and c represent the cost per cow. How much does Haley spend on each cow at the co-op?