The trafic light at three different road crossing change after every 4

1.	The trafic light at three different road crossing change after every 48 seconds and 72 seconds and 108 seconds respectively.If they change simultaneously at 7 am, at what time will they change simultaneously again?
Answer» ANSWER: 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 Step-by-step explanation: Hence the lights change simultaneously at 7:07:12 a.m

The trafic light at three different road crossing change after every 48 seconds and 72 seconds and 108 seconds respectively.If they change simultaneously at 7 am, at what time will they change simultaneously again?

Answer»

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

Step-by-step explanation:

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