A mountain road is 2.4 kilometers long. Uncle Wang walked up the mountain for 1.6 hours and down the mountain at 3 kilometers per hour. What is his average speed for going up and down the mountain?
一条山路有2.4千米，王大伯上山走了1.6小时，下山每小时走3千米，他上下山的平均速度是多少？
<gadget id="calculator">2.4 / 3</gadget>
<output>0.8</output>

<gadget id="calculator">1.6 + 0.8</gadget>
<output>2.4</output>

<gadget id="calculator">2 / 2.4</gadget>
<output>0.833333</output>

<gadget id="calculator">2.4 * 0.833333</gadget>
<output>1.999999</output>

<result>1.999999</result>