If each tire in the front of the car cost $12.40 more than the rear tires, then the total would be $24.80. And because we say that each tire for Luke's race tire is going to cost him $100 each, he would be paying $224.80 for the two front tires, while including both the cost of each tire and the additional 12.40.
Equation: 12.40(2) + 100(2) = 224.80