Each of bag of gravel, G, covers 12x square feet of land and costs $22. which of the following situations best models the minimum cost to completely cover the ground between the warehouse and the fence with gravel.
1. Find the product of the number of bags of gravel and the cost of the bag                       2. Find the sum of the number of bags of gravel and the cost per bag
3. Find the difference between the number of bags of gravel and cost per bag
4. none of the above