Math, asked by tanmaysinghpadrikhur, 6 months ago

The traffic light diffrent road crossing change after every 48 seconds, 72 seconds, 108 seconds,respectively. If they change simultaneosly at 7 am. At what time will they change simultaneosly again.

Answers

Answered by sachinbobbili17
1

Hence the lights will change simultaneously after 432 seconds = 7 minutes and 12 seconds after 7 am. Hence the lights will change simultaneously at 07:07:12 am(HH:MM: SS).

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Answered by BrainlyPARCHO
0

 \large \green{  \fcolorbox{gray}{black}{ ☑ \:  \textbf{Verified \: answer}}}

If the traffic lights change simultaneously at 7 a.m, then they will change simultaneously again after the LCM of the duration i.e. 48 s, 72 s and 108 s.

LCM of these durations by prime factorisation

  • 48 = 2 × 2 × 2 × 2 × 3 = 2⁴ × 3
  • 72 = 2 × 2 × 2 × 3 × 3 = 2³ × 3²
  • 108 = 2 × 2 × 3 × 3 × 3 = 2² × 3³

LCM of 48, 72 and 108 is 2⁴ × 3³ = 432 seconds.

Hence, They will change after 432 seconds i.e. 7 minutes 12 seconds.

The traffic lights will change after:

  • 7 am + 7 minutes 12 seconds
  • 07 : 07 : 12 am
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