The speed ratio of cars A, B, and C is 11:9:7. The three cars start at the same time. Car A travels from the east station to the west station, and cars B and C travel from the west station to the east station. Car B traveled an extra 54 kilometers. When Car A and C met, how many kilometers did Car C travel?
甲乙丙三车的速度比是11：9：7，三车同时出发，甲车从东站向西站行驶，乙丙两车从西站向东站行驶，甲乙两车相遇时，甲车比乙车多行了54千米，甲丙相遇时，丙车行了多少千米．
<gadget id="calculator">11 - 9</gadget>
<output>2</output>

<gadget id="calculator">54 / 2</gadget>
<output>27</output>

<gadget id="calculator">11 + 9</gadget>
<output>20</output>

<gadget id="calculator">11 + 7</gadget>
<output>18</output>

<gadget id="calculator">7 / 18</gadget>
<output>7/18 = around 0.388889</output>

<gadget id="calculator">27 * 20 * (7/18)</gadget>
<output>210</output>

<result>210</result>