The distance between A and B is 581 kilometers. A car travels 249 kilometers from A to B in 3 hours. At this speed, how many hours will it take to reach B?
甲乙两城相距581千米，一辆汽车从甲城开往乙城，3小时行了249千米，照这样的速度，一共需要多少小时才能到达乙地？
<gadget id="calculator">249 / 3</gadget>
<output>83</output>

<gadget id="calculator">581 / 83</gadget>
<output>7</output>

<result>7</result>