On Saturday, Xiao Ming walked to the ladder to play. He walked 60 meters per minute, walked for 12 minutes, and took 8 minutes to get down the ladder. What is the average speed of Xiao Ming going up and down the ladder?
星期六，小明步行去天梯玩，去时每分钟行60米，步行了12分钟，下天梯用了8分钟，求小明上、下天梯的平均速度是多少？
<gadget id="calculator">60 * 12 * 2</gadget>
<output>1_440</output>

<gadget id="calculator">12 + 8</gadget>
<output>20</output>

<gadget id="calculator">1_440 / 20</gadget>
<output>72</output>

<result>72</result>