If the length and width of a rectangle are increased by 12 centimeters, then its area will increase by 384 square centimeters. What is the perimeter of the original rectangle in centimeters?
一个长方形如果它的长和宽都增加12厘米，那么它的面积就增加384平方厘米，原来长方形的周长是多少厘米．
<gadget id="calculator">20 * 2</gadget>
<output>40</output>

<result>40</result>