The road between A and B is 170 kilometers long. A car drives from place A to place B and travels 68 kilometers in the first two hours. According to this calculation, how many hours can it reach place B? (Solve with ratio)
甲乙两地之间的公路长170千米．一辆汽车从甲地开往乙地，头两小时行驶了68千米，照这样计算，几小时可以到达乙地？(用比例解)
<gadget id="calculator">170 * 2</gadget>
<output>340</output>

<gadget id="calculator">340 / 68</gadget>
<output>5</output>

<result>5</result>