The total length from A to B is 42 kilometers. From A to B, according to the regulations of the Price Bureau, the fee is 12.5 yuan for the first 3 kilometers, and 2.5 yuan for each kilometer thereafter. How much does he have to pay in total?
从甲地到乙地全长42千米，小李从甲到乙，按物价局规定，前3千米收费12.5元，以后每千米收2.5元，一共要付多少元？
<gadget id="calculator">42 - 3</gadget>
<output>39</output>

<gadget id="calculator">39 * 2.5</gadget>
<output>97.5</output>

<gadget id="calculator">97.5 + 12.5</gadget>
<output>110</output>

<result>110</result>