There are two ropes of the same length, the first one is cut into 3 pieces on average, and the second one is cut into 7 pieces on average. Each segment cut from the first root is 8 meters longer than each segment cut from the second root. How long is each rope in meters?
有两根同样长的绳子，第一根平均剪成3段，第二根平均剪成7段．第一根剪成的每段比第二根剪成的每段长8米．原来每根绳子长多少米．
<gadget id="calculator">1 / 3</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">1 / 7</gadget>
<output>1/7 = around 0.142857</output>

<gadget id="calculator">(1/3) - (1/7)</gadget>
<output>4/21 = around 0.190476</output>

<gadget id="calculator">8 / (4/21)</gadget>
<output>42</output>

<result>42</result>