The traffic light at 3 diffrent road crossing change after every 48 sec. 72sec.and 100sec.respectively. if they change simultaneously at 8 am,at what time will they change again simultaneously.

Asked by manjarirawat373 | 19th Feb, 2019, 04:56: PM

Expert Answer:

 
 
Prime factorisation of 48, 72 and 100.
 
48 = 2 × 2 × 2 × 2 × 3
72  =  2 × 2 × 2 × 3 × 3
100 = 2 × 2 × 5 × 5

LCM(48, 72, 100) = 3600
 
3600 seconds = 60 mins = 1 hour
 
Therefore at 8 + 1 = 9am they change again simultaneously.

Answered by Yasmeen Khan | 20th Feb, 2019, 12:35: PM