The students in class 4 and 1 went to climb the mountain. The average speed of going up the mountain was 480 m/h. It took 4 hours to go up the mountain, and it took only 2 hours to go back down the mountain. What is the average speed of the students going up and down the mountain?
四1班的同学们去爬山，上山的平均速度是480米/时，上山用了4小时，沿原路返回，下山只用了2小时，同学们上山、下山的平均速度是多少？
<gadget id="calculator">4 + 2</gadget>
<output>6</output>

<gadget id="calculator">2 / 6</gadget>
<output>1/3 = around 0.333333</output>

<gadget id="calculator">480 * 4 * (1/3)</gadget>
<output>640</output>

<result>640</result>