The school organizes students to conduct marching training. Class 61 walks 11.25 kilometers in 3 hours; Class 62 walks 4.5 kilometers per hour. How much more miles per hour does Class 62 walk on average than Class 61?
学校组织学生进行行军训练，六一班3小时走完11.25千米；六二班每小时走了4.5千米．六二班比六一班平均每小时多走多少千米？
<gadget id="calculator">11.25 / 3</gadget>
<output>3.75</output>

<gadget id="calculator">4.5 - 3.75</gadget>
<output>0.75</output>

<result>0.75</result>