There is an electronic clock that rings every hour and lights up every 18 minutes. At 12:00 noon, it both rings and turns on the light. When is the next time it rings and turns on the light?
有一种电子钟，每到整点响一次铃，每走18分钟亮一次灯．中午12点整，它既响铃又亮灯，问下一次既响铃又亮灯是什么时候？
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