The convoy transported a batch of materials to the disaster area, traveled 60km per hour, and arrived at the disaster area in 6.5 hours. When returning, travel 78km per hour, how long will it take to return to the starting point? (Solve with ratio)
车队向灾区运送一批物资，去时每小时行60km，6.5小时到达灾区．回来时每小时行78km，多长时间能够返回出发点？(用比例解)
<gadget id="calculator">6.5 * 60</gadget>
<output>390</output>

<gadget id="calculator">390 / 78</gadget>
<output>5</output>

<result>5</result>