A cuboid with a length of 30 cm and a square cross section, if the length is increased by 5 cm, the surface area will increase by 80 cm2, find the surface area of the original cuboid.
一个长30厘米，截面是正方形的长方体，如果长增加5厘米，表面积就增加80平方厘米，求原长方体的表面积．
<gadget id="calculator">80 / 5</gadget>
<output>16</output>

<gadget id="calculator">16 / 4</gadget>
<output>4</output>

<gadget id="calculator">4 * 4 * 2</gadget>
<output>32</output>

<gadget id="calculator">4 * 30 * 4</gadget>
<output>480</output>

<gadget id="calculator">32 + 480</gadget>
<output>512</output>

<result>512</result>