cone and a cylinder have the same base and height, and the sum of their volumes is 12 cubic decimeters. What is the volume of the cone?
一个圆锥和一个圆柱等底等高，它们体积的和是12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">12 / 4</gadget>
<output>3</output>

<result>3</result>