The speed of a warship in still water is 54 kilometers per hour, and the speed of sea water is 16 kilometers per hour. How many hours will it take to sail 798 kilometers against the current?
一艘军舰的静水速度为每小时54千米，海水的速度是每小时16千米，逆水航行798千米，需要用多少小时．
<gadget id="calculator">54 - 16</gadget>
<output>38</output>

<gadget id="calculator">798 / 38</gadget>
<output>21</output>

<result>21</result>