The highway from the county seat to the provincial capital is 480 kilometers long. A car travels at a speed of 80 km/h on a highway and at 40 km/h on an ordinary road. How much time do you save by taking the highway instead of the normal road?
县城到省城的公路长480千米．一辆汽车走高速路的速度是80千米/时，走普通公路的速度是40千米/时．走高速公路比普通公路节省多少时间？
<gadget id="calculator">480 / 40</gadget>
<output>12</output>

<gadget id="calculator">480 / 80</gadget>
<output>6</output>

<gadget id="calculator">12 - 6</gadget>
<output>6</output>

<result>6</result>