There is a batch of books. If every 25 books are bundled into a bundle, 60 bundles need to be bundled. If every 30 books are bundled into a bundle, how many bundles should be bundled?
有一批书，如果每25本捆成一包，需要捆60包，如果每30本捆成一包，需捆多少包？
<gadget id="calculator">60 / 30</gadget>
<output>2</output>

<gadget id="calculator">25 * 2</gadget>
<output>50</output>

<result>50</result>