The distance between A and B cities is 420 kilometers. A car travels 168 kilometers in 4 hours. How many hours will it take to complete the journey?
甲乙两城相距420千米，一辆汽车4小时行驶168千米，行完全程需几小时？
<gadget id="calculator">168 / 4</gadget>
<output>42</output>

<gadget id="calculator">420 / 42</gadget>
<output>10</output>

<result>10</result>