The road from city A to city B is 150 kilometers long. A car travels at a speed of 75 km/h on a highway and at 50 km/h on an ordinary road. How much time is saved by taking the expressway from city A to city B compared to ordinary roads?
A城到B城的公路长150千米．一辆汽车走高速路的速度是75千米/时，走普通公路的速度是50千米/时．从A城去B城走高速路比普通公路节省多少时间？
<gadget id="calculator">150 / 50</gadget>
<output>3</output>

<gadget id="calculator">150 / 75</gadget>
<output>2</output>

<gadget id="calculator">3 - 2</gadget>
<output>1</output>

<result>1</result>