A minibus drives from place A to place B. It travels an average of 40 kilometers per hour and arrives at place B in 4.5 hours. It takes 0.5 hours less than before to return. This minibus travels an average of kilometers per hour when it returns?
一辆中巴车从甲地开行为表现乙地，平均每小时行驶40千米，4.5小时到达乙地，返回时比原来少用了0.5小时．这辆中巴车返回时平均每小时行驶千米？
<gadget id="calculator">4.5 - 0.5</gadget>
<output>4</output>

<gadget id="calculator">4.5 / 4</gadget>
<output>1.125</output>

<gadget id="calculator">40 * 1.125</gadget>
<output>45</output>

<result>45</result>