Rocky Mountain Tire Center sells $$go$-$cart tires per year. The ordering cost for each order is $$$$,$ and the holding cost is $\%$ of the purchase price of the tires per year. The purchase price is $$$ per tire if fewer than tires are$$ ordered, $$$ per tire if or morebut fewer than tires are$$ ordered, and $$$ per tire if or more tires are ordered.

Part $2$