cylinder and a cone have the same base radius and height. If the sum of their volumes is 8 cubic decimeters, what is the volume of the cone?
一个圆柱和一个圆锥的底面半径和高都相等．已知它们的体积之和是8立方分米，则圆锥的体积是多少立方分米．
<gadget id="calculator">1 + 3</gadget>
<output>4</output>

<gadget id="calculator">8 / 4</gadget>
<output>2</output>

<result>2</result>