From the school to the library, Dongdong walks 4.5km per hour and can arrive in 0.6 hours. If it takes 0.5 hours to arrive, how many kilometers should be traveled per hour?
东东从学校到图书馆，每小时走4.5km，0.6小时可以到达．如果要0.5小时到达，每小时应走多少千米？
<gadget id="calculator">0.6 / 0.5</gadget>
<output>1.2</output>

<gadget id="calculator">4.5 * 1.2</gadget>
<output>5.4</output>

<result>5.4</result>