A rope is cut off by 20%, and then 6 meters are connected. The result is 30% longer than the original rope. How many meters is this rope?
一根绳子截去20%后，再接上6米，结果比原来的绳子还长30%，这根绳子原来多少米？
<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">1 + (3/10)</gadget>
<output>13/10 = around 1.3</output>

<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/5)</gadget>
<output>4/5 = around 0.8</output>

<gadget id="calculator">(13/10) - (4/5)</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">6 / (1/2)</gadget>
<output>12</output>

<result>12</result>