The convoy transported materials to the disaster area, traveled 60 kilometers per hour, and reached the disaster area in 6 hours. When you come back, travel 72 kilometers per hour, how many hours can you return? (Solve with ratio)
车队向灾区运送物资，去时每小时行60千米，6小时到达灾区．回来时每小时行72千米，多少小时能返回？(用比例解)
<gadget id="calculator">60 * 6</gadget>
<output>360</output>

<gadget id="calculator">360 / 72</gadget>
<output>5</output>

<result>5</result>