The charging standard of a taxi in a certain city is: 9 yuan within 3 kilometers, 2.4 yuan per kilometer beyond 3 kilometers. On Saturday, Yang Hong took a taxi from home to Bookstore and paid 28.2 yuan. rice.
某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，周六杨红从家打车去书城共付了28.2元，她家到书城有多少千米．
<gadget id="calculator">28.2 - 9</gadget>
<output>19.2</output>

<gadget id="calculator">19.2 / 2.4</gadget>
<output>8</output>

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

<result>11</result>