The school took group photos for the three good students, and only charged 5.7 yuan for one negative and three photos, and 0.4 yuan for an additional photo. There are 45 Miyoshi students. If each person wants a photo, how much will each person pay on average?
学校为三好学生集体拍照，一张底片和三张照片只收成本费5.7元，加洗一张0.4元．三好学生有45人，如果每人要一张照片，平均每人要付多少元？
<gadget id="calculator">45 - 3</gadget>
<output>42</output>

<gadget id="calculator">42 * 0.4</gadget>
<output>16.8</output>

<gadget id="calculator">16.8 + 5.7</gadget>
<output>22.5</output>

<gadget id="calculator">22.5 / 45</gadget>
<output>0.5</output>

<result>0.5</result>