The starting price of a taxi in a certain city is 8 yuan, and it is 2 yuan per kilometer after more than three kilometers. How much should Mr. Li pay for driving 18 kilometers in a taxi?
某市出租车的起步价是八元钱，超过三公里以后是每公里2元，李老师坐出租车行驶了18公里，应付多少钱．
<gadget id="calculator">18 - 3</gadget>
<output>15</output>

<gadget id="calculator">2 * 15</gadget>
<output>30</output>

<gadget id="calculator">30 + 8</gadget>
<output>38</output>

<result>38</result>