Xiao Li climbed the mountain. It took him 12 minutes to go up, an average of 50 meters per minute, and 8 minutes to return. How many meters per minute did he walk back and forth?
小李爬山，去时用了12分钟上，平均每分钟走50米，回来时用了8分钟，他往返平均每分钟走多少米？
<gadget id="calculator">12 + 8</gadget>
<output>20</output>

<gadget id="calculator">2 / 20</gadget>
<output>1/10 = around 0.1</output>

<gadget id="calculator">12 * 50 * (1/10)</gadget>
<output>60</output>

<result>60</result>