Uncle Wang set off from the foot of the mountain at 6:00 in the morning, reached the top of the mountain, and returned to the foot of the mountain at 2:00 pm. It is 12 kilometers from the foot of the mountain to the top of the mountain, so what is the average speed of Uncle Wang during this time?
王大爷早晨6：00从山脚出发，到达山顶后，下午2点有返回到山脚．从山脚到山顶有12千米，那么王大爷在这段时间中的平均速度是多少？
<gadget id="calculator">2 / 8</gadget>
<output>1/4 = around 0.25</output>

<gadget id="calculator">12 * (1/4)</gadget>
<output>3</output>

<result>3</result>