There are two pieces of cloth, one is 40 meters long and the other is 30 meters long. After using up the same part of the two pieces of cloth, it is found that the remaining length of the short piece of cloth is equal to the remaining length of the long piece of cloth (5 /7), how many meters is used for each piece of cloth?
有两段布，一段布长40米，另一段长30米，把两段布都用去同样长的一部分后，发现短的一段布剩下的长度是长的一段布所剩长度的(5/7)，每段布用去多少米？
<gadget id="calculator">5 / 7</gadget>
<output>5/7 = around 0.714286</output>

<gadget id="calculator">40 * (5/7)</gadget>
<output>200/7 = around 28.571429</output>

<gadget id="calculator">30 - (200/7)</gadget>
<output>10/7 = around 1.428571</output>

<gadget id="calculator">1 - (5/7)</gadget>
<output>2/7 = around 0.285714</output>

<gadget id="calculator">(10/7) / (2/7)</gadget>
<output>5</output>

<result>5</result>