The waterway between A and B is 504 kilometers long. Xiao Ming boards the boat from A at 7:00 am and arrives at B at 21:00. How many kilometers does the ship travel per hour on average?
甲、乙两港间的水路长504千米，小明上午7：00从甲地上船，21：00到达乙地，这艘船平均每小时航行多少千米？
<gadget id="calculator">504 / 14</gadget>
<output>36</output>

<result>36</result>