The road from a certain county to the provincial capital is 200 kilometers long. A car travels at a speed of 100 km/h on a highway and at 50 km/h on an ordinary road. How much time is saved by taking the adjusted road from the county seat to the provincial capital compared with the ordinary road?
某县城到省城的公路长200千米．一辆汽车走高速路的速度是100千米/时，走普通公路的速度是50千米/时．从县城去省城走调整路比普通公路节省多少时间？
<gadget id="calculator">200 / 50</gadget>
<output>4</output>

<gadget id="calculator">200 / 100</gadget>
<output>2</output>

<gadget id="calculator">4 - 2</gadget>
<output>2</output>

<result>2</result>