A road, the ratio of the length of the repaired to the unrepaired is 6:7, and after another 210 kilometers have been repaired, the ratio of the length of the repaired to the unrepaired is 9:4, what is the total length of this road?
一条路，修了的和没修的长度比是6：7，又修了210千米后，修了的和没修的长度比是9：4，这条路全长是多少？
<gadget id="calculator">9 + 4</gadget>
<output>13</output>

<gadget id="calculator">9 / 13</gadget>
<output>9/13 = around 0.692308</output>

<gadget id="calculator">6 + 7</gadget>
<output>13</output>

<gadget id="calculator">6 / 13</gadget>
<output>6/13 = around 0.461538</output>

<gadget id="calculator">(9/13) - (6/13)</gadget>
<output>3/13 = around 0.230769</output>

<gadget id="calculator">210 / (3/13)</gadget>
<output>910</output>

<result>910</result>