A cylindrical round steel with a length of 15 decimeters is cut into three sections on average to form 3 small cylinders, and the surface area increases by 16 square decimeters. What is the original volume of this round bar in cubic decimeters?
一根长15分米的圆柱体圆钢，平均截成三段成为3个小圆柱体，则表面积增加了16平方分米．这根圆钢原来的体积是多少立方分米．
<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<gadget id="calculator">4 * 15</gadget>
<output>60</output>

<result>60</result>