The traffic signal lights at three different road crossings change after 48 sec., 72 sec. and 108 sec. respectively. If they all change simultaneously at 8 : 20 : 00 hours, then at what time will they again change simultaneously?
1
8 : 27 : 12 hours
2
8 : 30 : 00 hours
3
8 : 54 : 10 hours
4
None of these