Two trains, A and B, run towards each other from A and B at the same time. Train A travels an average of 120 kilometers per hour, and train B travels an average of 110 kilometers per hour. They meet each other in 3 hours. How many kilometers are there between A and B?
甲，乙两列火车同时从A、B两地相向而行，甲车平均每小时行驶120千米，乙车平均每小时行驶110千米，3小时相遇．A、B两地相距多少千米？
<gadget id="calculator">120 + 110</gadget>
<output>230</output>

<gadget id="calculator">230 * 3</gadget>
<output>690</output>

<result>690</result>