The distance between A and B is 48 kilometers, part of which is uphill, and the rest is downhill. A person rides a bicycle from place A to place B and then returns to place A along the same road. It takes 4 hours and 12 minutes to go there, and 24 minutes less time to return. It is known that the bicycle travels 10 kilometers per hour when going uphill, how many kilometers per hour does the bicycle travel when going downhill?
甲乙两地相距48千米，其中一部分是上坡路，其余的是下坡路．某人骑自行车从甲地到乙地后沿原路返回甲地，去时用4小时12分，返回时所用的时间比去时少24分钟．已知自行车上坡时每小时行10千米，求自行车下坡时每小时行多少千米？
<gadget id="calculator">48 / 10</gadget>
<output>24/5 = around 4.8</output>

<gadget id="calculator">8 - (24/5)</gadget>
<output>16/5 = around 3.2</output>

<gadget id="calculator">48 / (16/5)</gadget>
<output>15</output>

<result>15</result>