Uncle workers have built a road, and 35% of the whole journey has been repaired. It is still 3 kilometers away from the midpoint. How many kilometers have been repaired?
工人叔叔修一条公路，已修了全程的35%，离中点还差3千米，已修了多少千米？
<gadget id="calculator">1 / 2</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">35 / 100</gadget>
<output>7/20 = around 0.35</output>

<gadget id="calculator">(1/2) - (7/20)</gadget>
<output>3/20 = around 0.15</output>

<gadget id="calculator">3 / (3/20)</gadget>
<output>20</output>

<gadget id="calculator">20 * (7/20)</gadget>
<output>7</output>

<result>7</result>