The traffic lights at three different roads crossing change after every 48 seconds ,72 seconds and 108 seconds respectively. If they all change simultaneously at 8 a.m . Then at what time will they again change simultaneously

 

Asked by rakshitasingh973 | 30th Jun, 2021, 12:07: PM

Expert Answer:

LCM of the three timings will give us the required time
Let's find LCM (48, 72, 108)
48 = 2 x 2 x 2 x 2 x 3
72 = 2 x 2 x 2 x 3 x 3
108 = 2 x 2 x 3 x 3 x 3
LCM = 2 x 2 x 2 x 2 x 3 x 3 x 3 = 432 seconds = 7 min 12 seconds

Answered by Renu Varma | 1st Jul, 2021, 11:33: AM