Xiao Ming walks 10 kilometers in 2.5 hours, what is his walking speed in kilometers per hour? If Xiaoming walks at a constant speed, what is the proportional relationship between his walking distance and time?
小明2.5小时步行10千米，他的步行速度是每小时多少千米？如果小明步行的速度一定，他的行走路程和时间成什么比例关系．
<gadget id="calculator">10 / 2.5</gadget>
<output>4</output>

<result>4</result>