The charging standard of a certain taxi is: the starting price is 6 yuan (that is, the fare is 6 yuan for a driving distance of no more than 3 kilometers), and after 3 kilometers, an additional 1.5 yuan is charged for each additional kilometer (less than 1 kilometer is charged as a fare). 1 kilometer), a person pays 18 yuan to take this kind of taxi from A to B, what is the maximum distance traveled by this person in kilometers?
某种出租车收费标准是：起步价6元(即行驶距离不超过3千米需付6元车费)，超过3千米以后，每增加1千米加收1.5元(不足1千米按1千米计)，某人乘这种出租车从甲地到乙地支付车费18元，此人路程的最大距离为多少千米．
<gadget id="calculator">18 - 6</gadget>
<output>12</output>

<gadget id="calculator">12 / 1.5</gadget>
<output>8</output>

<gadget id="calculator">3 + 8</gadget>
<output>11</output>

<result>11</result>