The speed of the car going up the mountain is 36 km/h. It takes 5 hours to reach the top of the mountain, and it only takes 4 hours to go down the mountain and return the same way. What is the speed of the car when going down the mountain?
汽车上山的速度为36千米/时，行了5小时到达山顶，下山按原路返回只用了4小时，汽车下山时的速度是多少？
<gadget id="calculator">5 / 4</gadget>
<output>5/4 = around 1.25</output>

<gadget id="calculator">36 * (5/4)</gadget>
<output>45</output>

<result>45</result>