On the first day of school, 12 students from Class 51 took a group photo. You pay 20 yuan for one shot, and 2.5 yuan for one more photo for 4 photos. How much would they pay if each person wanted a photo?
开学第一天，五1班12位同学照合影留念．拍一次付20元，给4张照片，加洗一张另付2.5元．如果每人要一张照片，他们一共要付多少钱？
<gadget id="calculator">12 - 4</gadget>
<output>8</output>

<gadget id="calculator">8 * 2.5</gadget>
<output>20</output>

<gadget id="calculator">20 + 20</gadget>
<output>40</output>

<result>40</result>