Students from Xinya Primary School participated in the spring outing. The school bus went up the mountain at a speed of 36 kilometers per hour. It took 5 hours to go up the mountain, but it only took 4 hours to go down the mountain. How many kilometers does the school bus travel per hour when it goes downhill?
新亚小学的同学参加春游．校车上山时速度为每小时36千米，行了5小时，下山时只用了4小时．校车下山时每小时行多少千米？
<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>