(2/5) of a road has been repaired, and if another 3000 meters are repaired, half of the road can be repaired. How long is this road in meters?
一条公路已经修了它的(2/5)，再修3000米，就能修好这条公路的一半．这条公路全长多少米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">(1/2) - (2/5)</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">3_000 / (1/10)</gadget>
<output>30_000</output>

<result>30_000</result>