After 20% of a plastic rope is used up, 6 decimeters (not including the rope used for the joint) are connected, which is more (2/5) than the original full length at this time. How many decimeters are there in this plastic rope?
一根塑料绳用去20%后又接上6分米(不包括接头的用绳)，这时比原来的全长多(2/5)，这根塑料绳原来有多少分米？
<gadget id="calculator">20 / 100</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/5) + (2/5)</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">6 / (3/5)</gadget>
<output>10</output>

<result>10</result>