60% of the highway has been built, and there are still 20 kilometers left to be repaired. How many kilometers is the highway?
修一段高速公路，已经修了60%，还剩下20千米没有修，这段高速公路长多少千米？
<gadget id="calculator">60 / 100</gadget>
<output>3/5 = around 0.6</output>

<gadget id="calculator">1 - (3/5)</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">20 / (2/5)</gadget>
<output>50</output>

<result>50</result>