$4\mathrm{.}3\mathrm{.}19)$ A tire company has two plants, one in Dallas and one in New Orleans. The Dallas plant can make $800$ radial and $280$ standard tiers per day. The New Orleans plant can make $500$ radial and $150$ standard tires per day. It costs $$22,000$ per day to operate the Dallas plant and $$12,000$ per day to operate the New Orleans plant. The company has a contract to make at least $28,000$ radial and $9000$ standard tires. How many days should each plant be scheduled to minimize operating costs?

Dallas:

New Orleans:

Operating Costs: