The school organized a spring outing for the students. The speed of the bus was 36 kilometers per hour when going up the mountain, and it took 5 hours. It only took 4 hours to go down the mountain. How many kilometers per hour does the passenger car travel on average when going down the mountain?
学校组织学生春游，客车上山时的速度为每小时36千米，共用了5小时，下山时只用了4小时．客车下山时平均每小时行多少千米？
<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>