circle of metal wires is 30 meters long, and 3 metal wires of length A and 5 metal wires of length B are cut off. If two metal wires of length B are cut off from the remaining metal wires, the difference is still 0.4 meters. Intercepting two metal wires with length A is still 2 meters short, how many meters is equal to the length A?
一圈金属线长30米，截取长度为A的金属线3根，长度为B的金属线5根，剩下的金属线如果再截取2根长度为B的金属线还差0.4米，如果再截取2根长度为A的金属线则还差2米，长度为A的等于几米？
<gadget id="calculator">2 - 0.4</gadget>
<output>1.6</output>

<gadget id="calculator">1.6 / 2</gadget>
<output>0.8</output>

<gadget id="calculator">0.8 * 5</gadget>
<output>4</output>

<gadget id="calculator">4 + 2 + 30</gadget>
<output>36</output>

<gadget id="calculator">3 + 5 + 2</gadget>
<output>10</output>

<gadget id="calculator">36 / 10</gadget>
<output>18/5 = around 3.6</output>

<result>18/5 = around 3.6</result>