Question

traffic lights at three different road crossing change after 48 second, 72 second and 108 second respectively. at what time will the change together if they change simultaneously at 7am​

Answer 1

Step-by-step explanation:

Given :

• Traffic lights at three different road crossing change after 48 second, 72 second and 108 second respectively

• they change simultaneously at 7am

To Find :

• what time will the change together

Solution :

First we Find LCM

48 = 2⁴ x 3

72 = 2³ x 3²

108 = 2² x 3³

LCM = 2⁴ x 3³ = 423

Convert 432 sec to min and sec:

= 432 / 60

= 7. 12

So 7 mins 12 sec

The chansimultaneously at 7am together if they change

= 7 am + 7 mins 12 sec

= 7:07:12 am

• Hence The Answer: 7:07:12 am

Answer 2

Answer:

AFTER 432 SECOND

Step-by-step explanation:

GIVEN,

TIME TAKEN BY FIRST TRAFFIC LIGHT=48 SECOND

TIME TAKEN BY SECOND TRAFFIC LIGHT = 72 SECOND

TIME TAKEN BY THIRD TRAFFIC LIGHT=108 SECOND

TO FIND THE TIME AT  WHICH THEY CHANGE SIMUNLTANEOSLY,

WE HAVE TO FIND THE LCM OF 48,72,108=432 SECOND

SO,

THEY WILL CHANGE SIMULTANEOUSLY AFTER 432 SECOND AFTER 7 AM

I HOPE YOU UNDERSTOOD THE QUESTION