It is 960 kilometers from city A to city B. A passenger car travels 60 kilometers per hour, and a car travels 80 kilometers per hour. The two cars drive from city A to city B at the same time. How many hours before the passenger car arrives?
从A城到B城有960千米，一辆客车每小时行60千米，一辆轿车每小时行80千米，两车同时从A城开往B城，轿车比客车提前几小时到达？
<gadget id="calculator">960 / 60</gadget>
<output>16</output>

<gadget id="calculator">960 / 80</gadget>
<output>12</output>

<gadget id="calculator">16 - 12</gadget>
<output>4</output>

<result>4</result>