The speed of the car going up the mountain is 45 kilometers per hour. It takes 6 hours to reach the top of the mountain, and it only takes 5 hours to return to the same road when going down the mountain. How many kilometers per hour did the car travel on average when going downhill?
汽车上山的速度为每小时45千米，行了6小时到达山顶，下山时按原路返回只用了5小时．汽车下山时平均每小时行了多少千米？
<gadget id="calculator">6 / 5</gadget>
<output>6/5 = around 1.2</output>

<gadget id="calculator">45 * (6/5)</gadget>
<output>54</output>

<result>54</result>