The convoy delivered relief supplies to the disaster area, traveled 65 kilometers per hour, and arrived at the destination in 8.4 hours. When returning, if you travel 70 kilometers per hour, how long will it take you to return to the starting point?
车队向灾区运送救援物资，去时每小时行65千米，8.4小时到达目的地．返回时，如果每小时行70千米，多长时间能返回出发地点？
<gadget id="calculator">8.4 / 70</gadget>
<output>0.12</output>

<gadget id="calculator">65 * 0.12</gadget>
<output>7.8</output>

<result>7.8</result>