There is a cuboid water tank, the length and width are 2dm from the inside, pour 5.5L of water into the water tank, and then put an apple into the water, the water level in the water tank measured at this time is 20cm, what is the volume of this apple?
有一长方体的水箱，从里面量长宽均为2dm，向水箱里倒入5.5L水，再把一个苹果放入水中，这时量的水箱中的水位是20cm，这个苹果的体积是多少？
<gadget id="calculator">20 / 10</gadget>
<output>2</output>

<gadget id="calculator">2 * 2 * 2</gadget>
<output>8</output>

<gadget id="calculator">8 - 5.5</gadget>
<output>2.5</output>

<result>2.5</result>