The school bought 200 boxes of chalk for the first time, and 150 boxes for the second time. The first time paid 100 yuan more than the second time. How much is each box of chalk?
学校第一次买来200盒粉笔，第二次买来150盒，第一次比第二次多付100元，每盒粉笔多少元？
<gadget id="calculator">200 - 150</gadget>
<output>50</output>

<gadget id="calculator">100 / 50</gadget>
<output>2</output>

<result>2</result>