The rescue team rushes to repair a section of the tunnel. The repaired length accounts for 80% of the unrepaired length. If another 60 meters are repaired, the repaired length accounts for 7/5 of the unrepaired length. How long is this tunnel in meters?
救援队抢修一段隧道，已修的长度占未修的80%，若再修60米，则已修的长度占未修的(7/5)，这段隧道全长多少米？
<gadget id="calculator">7 + 5</gadget>
<output>12</output>

<gadget id="calculator">7 / 12</gadget>
<output>7/12 = around 0.583333</output>

<gadget id="calculator">4 + 5</gadget>
<output>9</output>

<gadget id="calculator">4 / 9</gadget>
<output>4/9 = around 0.444444</output>

<gadget id="calculator">(7/12) - (4/9)</gadget>
<output>5/36 = around 0.138889</output>

<gadget id="calculator">60 / (5/36)</gadget>
<output>432</output>

<result>432</result>