the traffic lights at three different road crossings change after every 48..., HCF & LCM, General Mathematics

Question: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 they will again change simultaneously at :

A 8 :27 : 12 hrs 
B 8 : 27 : 24 hrs 
C 8 : 27 : 36 hrs 
D 8 : 27 : 48 hrs

/49

+ AnswerA

+ Explanationsolution:
Interval of change = `(1.c.m. of 48, 72, 108) sec. = 432` sec.
`:.`The lights will change simultaneously after every 432 seconds, i.e. 7 min. 12 sec.
`:.` Next simultaneous change will take place at` 8 : 27 : 12` hrs.

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