The charging standard of Binjiang parking lot is as follows: at least 3 yuan for one parking, 2.5 yuan for each hour of parking for more than 2 hours (less than 1 hour is calculated as 1 hour), and 10.5 yuan for a car leaving. How many hours was the car parked?
滨江停车场收费标准如下：停1次至少要交费3元，超过2小时每停1小时(不足1小时按1小时计算)要多交2.5元，一辆车离开时交了10.5元，这辆车停了几小时？
<gadget id="calculator">10.5 - 3</gadget>
<output>7.5</output>

<gadget id="calculator">7.5 / 2.5</gadget>
<output>3</output>

<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<result>5</result>