The distance from the foot of the mountain to the top of the mountain is 2.85 kilometers. It took the students 2.5 hours to go up the mountain, and 3.5 hours to go down the mountain along the original road. What is the average speed of going up and down the mountain?
从山脚到山顶的路程是2.85千米，同学们上山用了2.5时，沿着原路下山用了3.5时，上山，下山的平均速度是多少？
<gadget id="calculator">2.5 + 3.5</gadget>
<output>6</output>

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

<gadget id="calculator">2.85 * (1/3)</gadget>
<output>0.95</output>

<result>0.95</result>