It takes 16 hours for a car to go from city A to city B, the speed is 78 km/h, and it takes 12 hours to return. Find the speed when returning.
一辆汽车从甲城到乙城需要16时，行驶的速度是78千米/时，返回时用了12小时，求返回时的速度．
<gadget id="calculator">78 / 12</gadget>
<output>13/2 = around 6.5</output>

<gadget id="calculator">16 * (13/2)</gadget>
<output>104</output>

<result>104</result>