Xiao Ming went to Beijing for a trip. It is known that Xiao Ming’s home is 450 kilometers away from Beijing. It took 5 hours to go there and 2 hours less to return. What is the velocity when returning?
小明去北京旅游，已知小明家距离北京450千米，去时用了5小时，返回时少用了2小时．返回时的速度是多少？
<gadget id="calculator">5 - 2</gadget>
<output>3</output>

<gadget id="calculator">450 / 3</gadget>
<output>150</output>

<result>150</result>