A local train and an express train depart from A and B oppositely at the same time. The local train travels 42 kilometers per hour, and the express train travels 68 kilometers per hour. They meet each other after 4 hours. How many kilometers are the two stations A and B?
一列慢车和一列快车同时从甲乙两站相对开出，慢车每小时行42千米，快车每小时行68千米，经过4小时相遇．甲乙两站相距多少千米？
<gadget id="calculator">42 + 68</gadget>
<output>110</output>

<gadget id="calculator">110 * 4</gadget>
<output>440</output>

<result>440</result>