In a mountaineering competition, Li Ming went uphill at 100 meters per minute and downhill at 150 meters per minute. How many meters does Li Ming walk up and down the mountain on average per minute?
在一次登山比赛中，李明上山每分钟100米，下山每分钟150米．李明上山、下山平均每分钟走多少米．
<gadget id="calculator">1 + 1</gadget>
<output>2</output>

<gadget id="calculator">1 / 100</gadget>
<output>1/100 = around 0.01</output>

<gadget id="calculator">1 / 150</gadget>
<output>1/150 = around 0.006667</output>

<gadget id="calculator">(1/100) + (1/150)</gadget>
<output>1/60 = around 0.016667</output>

<gadget id="calculator">2 / (1/60)</gadget>
<output>120</output>

<result>120</result>