Question

At two crossroads signals, lights change after every 25 seconds 45 seconds respectively. If they changed together at 9:20 am, then and n when will they change together next?​

Answer 1

Answer: 9:23:45 AM

Step-by-step explanation:

Street-light 1 → Changes every 25 seconds

Street-light 2 → Changes every 45 seconds

Given that both the lights changed at 9:20 AM, we need to find the LCM (Lowest Common Multiple) of the time taken by both the street-lights.

LCM of 25 and 45 = 225

225 seconds = 3.75 minutes = 3 minutes and 45 seconds

So, the street-lights will change together again at 9:23:45 AM where 45 are the seconds.