A road repairing team builds a road. The first time it repairs the total length (3/5) of 5 kilometers, and the second time it repairs 7 kilometers. At this time, the ratio of the repaired length to the unrepaired length is 9:1. How long is the road in kilometers?
一个修路队修一条公路，第一次修了全长的(3/5)多5千米，第二次修了7千米，这时已修的长度与未修的比是9：1，这段公路全长多少千米？
<gadget id="calculator">5 + 7</gadget>
<output>12</output>

<gadget id="calculator">9 + 1</gadget>
<output>10</output>

<gadget id="calculator">9 / 10</gadget>
<output>9/10 = around 0.9</output>

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

<gadget id="calculator">(9/10) - (3/5)</gadget>
<output>3/10 = around 0.3</output>

<gadget id="calculator">12 / (3/10)</gadget>
<output>40</output>

<result>40</result>