Two ships A and B are sailing towards each other from two docks at the same time. Ship A travels 40 kilometers per hour, and ship B travels 28 kilometers per hour. The two ships meet after traveling for 4 hours. How many kilometers are there between A and B?
甲乙两艘船分别从两个码头同时相向而行．甲船每小时行驶40千米，乙船每小时行驶28千米，两船行驶4小时后相遇．甲、乙两个码头相距多少千米？
<gadget id="calculator">40 + 28</gadget>
<output>68</output>

<gadget id="calculator">68 * 4</gadget>
<output>272</output>

<result>272</result>