A mom needs to stock up on school uniforms for her son and is comparing online and in-store pricing. At a store in her town, uniforms are sold for $45 for each set(any top and any bottom). Her town has a 7.25% sales tax. At the online store, she can purchase each piece for $20(any top or bottom). There is no sales tax and just flat rate shipping of $9.99. Write a cost model for the cost of a uniform set(includes 2 pieces) at the online store. Use meaningful variables and define them.