A cuboid with a length of 20 cm and a square cross section, if the length is increased by 5 cm, the surface area will increase by 40 cm2. Find the surface area of the original cuboid?
一个长20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40平方厘米，求原长方体的表面积？
<gadget id="calculator">40 / 5</gadget>
<output>8</output>

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

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

<gadget id="calculator">2 * 20 * 4</gadget>
<output>160</output>

<gadget id="calculator">8 + 160</gadget>
<output>168</output>

<result>168</result>