The ratio of the length to the width of a rectangle is 8:3. If the length is reduced (1/7) and the width is increased by 3 centimeters, it becomes a square. What is the length of the original rectangle in centimeters?
长方形的长和宽的比是8：3，若将长减少(1/7)，宽增加3厘米，就变成一个正方形，原长方形的长是多少厘米．
<gadget id="calculator">6 / 7</gadget>
<output>6/7 = around 0.857143</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(6/7) - (3/8)</gadget>
<output>27/56 = around 0.482143</output>

<gadget id="calculator">3 / (27/56)</gadget>
<output>56/9 = around 6.222222</output>

<result>56/9 = around 6.222222</result>