A car travels 108 kilometers per hour on the highway, which is 90 kilometers less than three times the speed on ordinary roads. What is the speed of this car on an ordinary road in kilometers?
一辆汽车在高速公路上每小时行驶108千米，比在普通公路行驶速度的3倍少90千米．这辆汽车在普通公路行驶的速度是多少千米？
<gadget id="calculator">108 + 90</gadget>
<output>198</output>

<gadget id="calculator">198 / 3</gadget>
<output>66</output>

<result>66</result>