To build a railway, the full length (1/4) was built in the first quarter, the full length (3/5) was repaired in the second quarter, and 27,000 meters was repaired in the third quarter, and it was just completed. How many kilometers is the total length of this railway?
修一条铁路，第一季度修了全长的(1/4)，第二季度修了全长的(3/5)，第三季度修了27000米，正好修完，这段铁路全长多少千米？
<gadget id="calculator">1 / 4</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">3 / 5</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">(1/4) + (3/5)</gadget>
<output>17/20 = around 0.85</output>

<gadget id="calculator">1 - (17/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">27_000 / (3/20) / 1_000</gadget>
<output>180</output>

<result>180</result>