The library bought 480 new books, which were placed on 4 shelves on average, and each shelf had 3 floors. How many new books are placed on each shelf on average per shelf?
图书馆买来新书480本，平均放在4个书架上，每个书架上有3层．平均每个书架上每层放多少本新书？
<gadget id="calculator">480 / 4 / 3</gadget>
<output>40</output>

<result>40</result>