The printing factory binds exercise books with a batch of paper. If each book has 50 pages, 120 books can be bound; if each book has 30 pages, how many books can be bound?
印刷厂用一批纸装订练习本．如果每本50页，可以装订120本；如果每本30页，可以装订多少本？
<gadget id="calculator">50 * 120</gadget>
<output>6_000</output>

<gadget id="calculator">6_000 / 30</gadget>
<output>200</output>

<result>200</result>