To build a road, the ratio of the kilometers that have been repaired to the kilometers that have not been repaired is 3:5. If another 12 kilometers are built, the ratio of the repaired and unrepaired kilometers is 9:1. How many kilometers is this road in total?
修一条路，已修和未修的千米数比是3：5．如果再修12千米，则已修和未修的千米数9：1，这条路共长多少千米？
<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>8</output>

<gadget id="calculator">3 / 8</gadget>
<output>3/8 = around 0.375</output>

<gadget id="calculator">(9/10) - (3/8)</gadget>
<output>21/40 = around 0.525</output>

<gadget id="calculator">12 / (21/40)</gadget>
<output>160/7 = around 22.857143</output>

<result>160/7 = around 22.857143</result>