Boat A travels 30 kilometers per hour, and boat B travels 26 kilometers per hour. The two boats set off at the same time with their backs facing each other for patrol. After 2 hours, boat A returns to catch up with boat B. How many hours later does it catch up with boat B?
甲船每小时行驶30千米，乙船每小时行驶26千米，两船同时同地背向出发巡逻，2小时后，甲船返回去追乙船，几小时后追上乙船？
<gadget id="calculator">30 + 26</gadget>
<output>56</output>

<gadget id="calculator">30 - 26</gadget>
<output>4</output>

<gadget id="calculator">2 / 4</gadget>
<output>1/2 = around 0.5</output>

<gadget id="calculator">56 * (1/2)</gadget>
<output>28</output>

<result>28</result>