Subject: General Aptitude · Chapter: H.C.F. and L.C.M. of Numbers · Exam: 2005 · Marks: · Difficulty:
The traffic lights at three different road crossings change after every 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?
Answer
Answer (as printed):
Explanation
Interval of change = (L.C.M. of 48, 72, 108) sec. = 432 sec. So, the lights will again change simultaneously after every 432 seconds, i.e., 7 min. 12 sec. Hence, next simultaneous change will take place at 8 : 27 : 12 hrs.
Explanation as extracted from the printed page; notation may be imperfect.