Honghong and Xiaoyang went climbing together. It took 3 hours to go up the mountain at 4km per hour, and it took 2 hours to go down the mountain and return along the same road. What is their average speed when going up and down the mountain?
红红和小洋同去登山，上山每小时行4km，用了3小时，下山沿原路返回，用了2小时，他们上，下山的平均速度是多少？
<gadget id="calculator">3 + 2</gadget>
<output>5</output>

<gadget id="calculator">2 / 5</gadget>
<output>2/5 = around 0.4</output>

<gadget id="calculator">4 * 3 * (2/5)</gadget>
<output>24/5 = around 4.8</output>

<result>24/5 = around 4.8</result>