An express train and an ordinary passenger train depart from two cities A and B at the same time. The express train travels 90 kilometers per hour, and the ordinary passenger train travels 48 kilometers per hour. After 2.5 hours, the two trains meet on the way. How long is the railway between A and B?
一列快车和一列普通客车从甲、乙两个城市同时相对开出，快车每小时行90千米，普通客车每小时行48千米，经过2.5小时后，两列火车在途中相遇．甲、乙两个城市间的铁路长多少千米？
<gadget id="calculator">90 + 48</gadget>
<output>138</output>

<gadget id="calculator">138 * 2.5</gadget>
<output>345</output>

<result>345</result>