A cylinder and a cone have the same base and height, and the sum of their volumes is 72 cubic decimeters. What is the volume of the cone?
一个圆柱和一个圆锥等底等高，它们的体积和是72立方分米，圆锥的体积是多少立方分米．
<gadget id="calculator">3 + 1</gadget>
<output>4</output>

<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">72 * (1/4)</gadget>
<output>18</output>

<result>18</result>