If a cylinder and a cone have the same base and height, and the volume difference is 20 cubic decimeters, what is the volume of the cone?
一个圆柱与圆锥等底等高，体积差是20立方分米，则圆锥的体积是多少立方分米．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">20 / (2/3)</gadget>
<output>30</output>

<gadget id="calculator">30 - 20</gadget>
<output>10</output>

<result>10</result>