A cone and a cylinder have the same base and height, and the sum of their volumes is 72 cubic centimeters, what is the volume of the cone in cubic centimeters?
一个圆锥与一个圆柱等底等高，它们的体积之和为72立方厘米，那么圆锥的体积是多少立方厘米．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">72 / 4</gadget>
<output>18</output>

<result>18</result>