A tram terminal leaves a tram at regular intervals. A and B walk in the same direction on the same street. A walks 80 meters per minute and encounters an oncoming tram every 3 minutes. He walks 60 meters per minute, and every 10 minutes a tram catches up with him from behind. Then how many minutes does a tram leave from the tram terminal?
一电车总站每隔一定时间开出一辆电车，甲和乙两人在一条街上沿着同一方向步行，甲每分钟步行80米，每隔3分钟遇上一辆迎面开来的电车；乙每分钟步行60米，每隔10分有一辆电车从后面追上他．则电车总站每隔多少分钟开出一辆电车？
<result>5</result>