Xinhua Bookstore needs to pack a batch of books. If each pack contains 40 books, it needs to bundle 18 packs. If there are 30 books per pack, how many packs should be bundled? (Solve with ratio)
新华书店要打包一批书，如果每包40本，要捆18包．如果每包30本，要捆多少包？(用比例解)
<gadget id="calculator">40 * 18</gadget>
<output>720</output>

<gadget id="calculator">720 / 30</gadget>
<output>24</output>

<result>24</result>