Two identical cylinders are joined together to form a larger cylinder with a length of 20 cm and a reduced surface area of 50 cm**2. What is the volume of each cylinder in cm**3?
两个完全一样的圆柱体接成一个更大的圆柱体，长20cm，表面积减少了50cm**2，原来每个圆柱体的体积是多少cm**3．
<gadget id="calculator">50 / 2</gadget>
<output>25</output>

<gadget id="calculator">20 / 2</gadget>
<output>10</output>

<gadget id="calculator">25 * 10</gadget>
<output>250</output>

<result>250</result>