Xiao Ming travels to a scenic spot on foot, walking 4.8 km per hour, and arrives in 2.5 hours. After visiting the scenic spot for 3 hours, he returned and walked 4km per hour. How long would it take Xiao Ming to return to the starting point?
小明徒步到某风景区旅游，每小时走4.8km，2.5小时到达．在景区参观了3小时后返回，每小时走4km，问小明需要几小时才能回到出发地？
<gadget id="calculator">2.5 / 4</gadget>
<output>0.625</output>

<gadget id="calculator">4.8 * 0.625</gadget>
<output>3</output>

<result>3</result>