The distance between A and B is 800 kilometers. A car starts from A to B at a speed of 80 km/h. It has traveled 640 kilometers. How many hours will it take to reach B?
甲乙两地相距800千米，一辆汽车以80千米/时的速度从甲地出发开往乙地，已经行640千米，还要行几小时可以到达乙地？
<gadget id="calculator">800 - 640</gadget>
<output>160</output>

<gadget id="calculator">160 / 80</gadget>
<output>2</output>

<result>2</result>