The school library buys 108 new books and puts them on 2 bookshelves on average. If each bookshelf has 3 floors, how many books are placed on each floor on average?
学校图书馆买回108本新书，平均放在2个书架上，如果每个书架有3层，平均每层放多少本书？
<gadget id="calculator">108 / 2 / 3</gadget>
<output>18</output>

<result>18</result>