There is a batch of apples, if each box contains 15 kg, 20 boxes should be packed; if each box contains 10 kg, how many boxes should be packed?
有一批苹果，如果每箱装15千克，要装20箱；若每箱装10千克，要装多少箱？
<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">15 * 2</gadget>
<output>30</output>

<result>30</result>