40% of a road has been repaired, and half of the road can be repaired by repairing another 300 meters. How many meters is the total length of this road?
一条公路已经修了40%，再修300米就可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">40 / 100</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">300 / (1/10)</gadget>
<output>3_000</output>

<result>3_000</result>