The speed of a car traveling on a highway is 90 kilometers per hour, which is twice the speed of driving on an ordinary road. What is the speed of this car in kilometers per hour on an ordinary road?
一辆汽车在高速公路上行驶的速度是每小时90千米，是在普通公路上行驶速度的2倍．这辆汽车在普通公路上行驶的速度是每小时多少千米？
<gadget id="calculator">90 / 2</gadget>
<output>45</output>

<result>45</result>