A car travels 117.6 kilometers in 2.1 hours. According to this calculation, how many hours will it take to travel 173.6 kilometers?
一辆汽车2.1小时行驶117.6千米，照这样计算，要行驶173.6千米，需要多少小时？
<gadget id="calculator">117.6 / 2.1</gadget>
<output>56</output>

<gadget id="calculator">173.6 / 56</gadget>
<output>3.1</output>

<result>3.1</result>