Two identical cubes are put together to form a cuboid, and the surface area is reduced by 30 square centimeters. What is the original surface area of each cube?
有两个相同的正方体拼成1个长方体，表面积减少了30平方厘米，原来每个正方体的表面积是多少平方厘米？
<gadget id="calculator">30 / 2</gadget>
<output>15</output>

<gadget id="calculator">6 * 15</gadget>
<output>90</output>

<result>90</result>