When a car goes up the mountain at 36 kilometers per hour, it takes 5 hours to reach the top of the mountain. When going down the mountain, it returns to the same road and only takes 3 hours to reach the bottom of the mountain. How many kilometers per hour does the car travel up and down the mountain on average?
一辆汽车上山时每小时36千米，用了5小时到达山顶，下山时原路返回，只用了3小时就到达山底．这辆汽车上、下山平均每小时行多少千米？
<gadget id="calculator">36 * 5 * 2</gadget>
<output>360</output>

<gadget id="calculator">5 + 3</gadget>
<output>8</output>

<gadget id="calculator">360 / 8</gadget>
<output>45</output>

<result>45</result>