The still water speeds of two ships, A and B, are 26 km/h and 20 km/h respectively. The two ships depart from port A along the current, and ship B is 3 hours ahead of ship A. If the water speed is 5 kilometers per hour, how many hours will it take for ship A to catch up with ship B?
甲、乙两船的静水速度分别为26千米每小时和20千米每小时，两船从A港顺水先后开出，乙船比甲船先行3小时．若水速为5千米每小时，则多少小时后甲船可以追上乙船？
<gadget id="calculator">20 * 3</gadget>
<output>60</output>

<gadget id="calculator">5 * 3</gadget>
<output>15</output>

<gadget id="calculator">60 + 15</gadget>
<output>75</output>

<gadget id="calculator">5 - 20 - 5</gadget>
<output>-20</output>

<gadget id="calculator">26 + (-20)</gadget>
<output>6</output>

<gadget id="calculator">75 / 6</gadget>
<output>25/2 = around 12.5</output>

<result>25/2 = around 12.5</result>