Question

The traffic lights at three different road crossings change after every 48 seconds, 72 seconds and

108 seconds respectively. If they change simultaneously at 7 a.m., at what time will they change

simultaneously again? Why it is recommended to stop the vehicle engine at the red light signal​

Answer 1

Answer:

hello

Step-by-step explanation:

good morning my all friends

Answer 2

Answer:

Here is your answer bro

Step-by-step explanation:

The traffic light at three different road crossing change after every 48 seconds,72 seconds and 108 seconds respectively.

So let us take the LCM of the given time that is 48 seconds, 72 seconds, 108 seconds

⇒ 48 = 2 × 2 × 2 × 2 × 3

⇒ 72 = 2 × 2 × 2 × 3 × 3

⇒ 108 = 2 × 2 × 3 × 3 × 3

Hence LCM of 48, 72 and 108 = (2 × 2 × 2 × 2 × 3 × 3 × 3)

LCM of 48, 72 and 108 = 432

So  after 432 seconds they will change simultaneously

We know that ,

60 seconds = 1 minute

So on dividing 432 / 60 we get 7 as quotient and 12 as reminder

Hence, 432 seconds = 7 min 12 seconds

∴ The time  = 7 a.m. + 7 minutes 12 seconds

Hence the lights change simultaneously at  7:07:12 a.m.

Please mark me as the brainliest.