Both the No. 52 and No. 67 buses depart at 6:00, the No. 52 bus departs every 3 minutes, and the No. 67 bus departs every 5 minutes. What is the time when the two buses depart at the same time?
52路和67路公交车都是6：00发头班车，52路每3分钟发一趟，67路每5分钟发一趟，这两路车再次同时发车的时间是多少．
<gadget id="calculator">3 * 5</gadget>
<output>15</output>

<result>15</result>