Annabella spends $2.25 per gallon on gas at the gas station. After driving a certain distance, she stops at a second gas station and spends $2.15 per gallon on gasoline. Annabella can express her average cost per gallon of gasoline as 2.25x+2.15(x+5)/2x+5. What is the meaning of the parts of this rational expression in the context of the situation?