The express train and the slow train are traveling towards each other at the same time from A and B respectively. The express train travels 80 kilometers per hour, and the slow train travels 70 kilometers per hour. After 3 hours, how many kilometers are the distance between A and B?
快车和慢车分别从甲地和乙地同时相向而行，快车每小时行80千米，慢车每小时行70千米，经过3小时相遇，甲乙两地相距多少千米？
<gadget id="calculator">80 + 70</gadget>
<output>150</output>

<gadget id="calculator">150 * 3</gadget>
<output>450</output>

<result>450</result>