Xiao Ming walks 40 meters per minute when going up the mountain, and 60 meters per minute when going down the mountain. (along the original road, the original road is 120 meters) Find the average speed of going up and down the mountain.
小明上山时每分钟走40米，下山时每分钟走60米．(沿原路，原路为120米)求上山、下山的平均速度．
<gadget id="calculator">120 * 2</gadget>
<output>240</output>

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

<gadget id="calculator">120 / 40</gadget>
<output>3</output>

<gadget id="calculator">2 + 3</gadget>
<output>5</output>

<gadget id="calculator">240 / 5</gadget>
<output>48</output>

<result>48</result>