The taxi charges in Nanjing are: 9 yuan within 3 kilometers, 2.4 yuan per kilometer beyond 3 kilometers, and 2 yuan for each additional fuel surcharge. On Saturday, Yang Hong paid a total of 18.2 yuan by taxi from his home to the bookstore. How many kilometers is it from his home to the bookstore?
南京市出租车的收费标准是：3千米以内收费9元，3千米以外每千米收费2.4元，另外每次加收燃油附加费2元．周六杨红从家坐出租车去书城共付了18.2元，他家到书城大约多少千米？
<gadget id="calculator">18.2 - 9 - 2</gadget>
<output>7.2</output>

<gadget id="calculator">7.2 / 2.4</gadget>
<output>3</output>

<gadget id="calculator">3 + 3</gadget>
<output>6</output>

<result>6</result>