The parking fee method of the Changjiang Road parking lot is: the first 3 hours, a total of 15 yuan; more than 3 hours, every 30 minutes (less than 30 minutes are counted as 30 minutes) 1.2 yuan. Uncle Zhang’s car parked in the Changjiang Road parking lot for 5 hours. How much is the parking fee?
长江路停车场的停车收费方法是：前3小时，共收费15元；超过3小时，每30分钟(不满30分钟按30分钟计)收费1.2元．张叔叔的车在长江路停车场共停5个小时，需要缴纳停车费多少元．
<gadget id="calculator">5 - 3</gadget>
<output>2</output>

<gadget id="calculator">2 / 0.5</gadget>
<output>4</output>

<gadget id="calculator">4 * 1.2</gadget>
<output>4.8</output>

<gadget id="calculator">15 + 4.8</gadget>
<output>19.8</output>

<result>19.8</result>