Question

7. The traffic lights at three different road junctions change after every 40 seconds,
60 seconds and 72 seconds respectively. If they changed simultaneously together at
8 a.m at the junctions, at what time will they simultaneously change together again?​

Answer 1

Answer:

This is an LCM related problem

After 360 seconds they will change again i.e after six minutes they will change again i.e at 8.06 am they will change again simultaneously.

Answer 2

Answer:

at 08:06 a.m.the traffic lights will change.

Step-by-step explanation:

1. first find GCD of 40,60,72seconds, then the answer is 360 seconds
2. change seconds to minutes, you get 6 m.
3. add it to 8 a.m.
4. which is 08:06 a.m.