The volume of a cylindrical bucket is 20 liters. A conical lead block with a base area of 1.5 square decimeters is completely placed in the bucket. The bucket can only hold 18.5 liters of water. Find the height of the lead block.
一个圆柱形水桶的容积是20升，把一个底面积为1.5平方分米的圆锥形铅块完全放在桶里，桶里只能容水18.5升，求这个铅块的高．
<gadget id="calculator">20 - 18.5</gadget>
<output>1.5</output>

<gadget id="calculator">3 / 1.5</gadget>
<output>2</output>

<gadget id="calculator">1.5 * 2</gadget>
<output>3</output>

<result>3</result>