Two trains leave opposite directions at the same time from two stations. Car A travels 45 kilometers per hour, and car B travels 55 kilometers per hour. After 2.5 hours, the two cars meet. How long is the railway between the two stations?
两列火车从两个车站同时相向开出．甲车每小时行45千米，乙车每小时行55千米，经过2.5小时两车相遇．两个车站之间的铁路长多少千米？
<gadget id="calculator">45 + 55</gadget>
<output>100</output>

<gadget id="calculator">100 * 2.5</gadget>
<output>250</output>

<result>250</result>