tourist bus and a truck set off from Nanjing at the same time and headed for Shanghai along the Luning Expressway. After 3 hours, the tourist bus has traveled 243 kilometers, and the truck has traveled 216 kilometers. How many kilometers less does the truck travel per hour than the tourist car?
一辆旅游车和一辆卡车同时从南京出发，沿泸宁高速公路开往上海．3小时后，旅游车行驶了243千米，卡车行驶了216千米，卡车平均每小时比旅游车少行驶多少千米？
<gadget id="calculator">243 / 3</gadget>
<output>81</output>

<gadget id="calculator">216 / 3</gadget>
<output>72</output>

<gadget id="calculator">81 - 72</gadget>
<output>9</output>

<result>9</result>