A rope, cut off the full length (1/3) for the first time, and cut off the remaining 30% for the second time. If the part cut off twice is 0.4 meters longer than the remaining part, what is the original length of the rope?
一根绳子，第一次剪去全长的(1/3)，第二次剪去余下部分的30%．若两次剪去的部分比余下的部分多0.4米，则这根绳子原来长多少米．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 - (1/3)</gadget>
<output>2/3 = around 0.666667</output>

<gadget id="calculator">30 / 100</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">(2/3) * (3/10)</gadget>
<output>1/5 = around 0.2</output>

<gadget id="calculator">1 - (1/3) - (1/5)</gadget>
<output>7/15 = around 0.466667</output>

<gadget id="calculator">(1/5) - (7/15)</gadget>
<output>-4/15 = around -0.266667</output>

<gadget id="calculator">(1/3) + (-4/15)</gadget>
<output>1/15 = around 0.066667</output>

<gadget id="calculator">0.4 / (1/15)</gadget>
<output>6</output>

<result>6</result>