The road from Guangfeng County to Nanchang is 300 kilometers long. The speed of a car on the expressway is 100 kilometers per hour, and the speed on the ordinary road is 50 kilometers per hour. Taking the expressway from the county to Nanchang is faster than the ordinary road. How much time is saved?
从广丰县城到南昌的公路长300千米，一辆汽车走高速公路的速度是100千米/小时，走普通公路的速度是50千米/小时，从县城去南昌走高速路比普通公路节省多少时间？
<gadget id="calculator">300 / 50</gadget>
<output>6</output>

<gadget id="calculator">300 / 100</gadget>
<output>3</output>

<gadget id="calculator">6 - 3</gadget>
<output>3</output>

<result>3</result>