In a mountaineering competition, Xiaohao went up the mountain and walked 30 meters per minute. After reaching the top of the mountain, he immediately went down the mountain at a speed of 50 meters per minute. What is the average speed of Xiaohao going up and down the mountain?
在一次登山比赛中，小豪上山每分钟走30米，到达山顶后，立即以每分钟50米的速度原路下山．求小豪上、下山的平均速度是多少？
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 30</gadget>
<output>1/30 = around 0.033333</output>

<gadget id="calculator">1 / 50</gadget>
<output>1/50 = around 0.02</output>

<gadget id="calculator">(1/30) + (1/50)</gadget>
<output>4/75 = around 0.053333</output>

<gadget id="calculator">2 / (4/75)</gadget>
<output>75/2 = around 37.5</output>

<result>75/2 = around 37.5</result>