A parking lot in a certain city stipulates that a parking fee of at least 5 yuan should be paid for one parking, and an additional 1.5 yuan will be charged for each additional hour of parking. Master Wang pays a parking fee of 15.5 yuan. How many hours does he park in the parking lot?
某市停车场规定，停车一次至少交停车费5元，超过2小时，每多停1小时加收1.5元，王师傅付停车费15.5元，他在停车场停车多少小时？
<gadget id="calculator">15.5 - 5</gadget>
<output>10.5</output>

<gadget id="calculator">10.5 / 1.5</gadget>
<output>7</output>

<gadget id="calculator">7 + 2</gadget>
<output>9</output>

<result>9</result>