The road between A and B is divided into two sections, uphill and downhill, with a total of 24 kilometers. Xiao Ming’s uphill speed is 4 km/h, and the downhill speed is 6 km/h. It takes 4.5 Hours, how many hours will it take to return.
甲、乙两地之间的道路分上坡和下坡两种路段，共24千米，小明上坡速度为4千米/时，下坡速度为6千米/时，去时用了4.5小时，则返回时用多少小时．
<gadget id="calculator">24 / 4</gadget>
<output>6</output>

<gadget id="calculator">24 / 6</gadget>
<output>4</output>

<gadget id="calculator">6 + 4</gadget>
<output>10</output>

<gadget id="calculator">10 - 4.5</gadget>
<output>5.5</output>

<result>5.5</result>