Today, my parents and I went to grandma’s house by car. We took the bus this time, and it took us 6 hours. I remember the last time we drove the same road by ourselves, it only took 4.5 hours. Dad told me Last time he drove at a speed of 80 kilometers per hour, so how many kilometers per hour does this bus travel on average?
今天，我和爸爸妈妈一起乘车到奶奶家去，我们这次是乘大巴去的，一共用了6个小时，记得上次我们自己开车走同一条路只用了4.5个小时，爸爸告诉我上次他开车的速度保持在每小时80km，那么这辆大巴平均每小时行驶多少千米呢？
<gadget id="calculator">4.5 / 6</gadget>
<output>0.75</output>

<gadget id="calculator">80 * 0.75</gadget>
<output>60</output>

<result>60</result>