Question

the traffic lights at three different road crossings change after every 35 seconds, 42 seconds and 70 seconds respectively. If they change simultaneously at 9 am, at what time will they change simultaneously next?


please solve it on paper if possible that I can understand clearly :):)


and I will Mark it as brainliest. ​

Answer 1

Answer:

The three lights will change simultaneously again at 9 hours 3 minutes 30 seconds in the morning, i.e., at 09:03:30 a.m.

Step-by-step explanation:

We know that in order to find the time when the three lights will change simultaneously again after 9 a.m., we need to find the LCM of 35,42, and 70.

Finding the LCM using the prime factorization method, we get the prime factors of LCM as :

Factors = 7 x 5 x 2 x 3 = 210

Hence, after converting 210 seconds into minutes and seconds, we get:

210 seconds = 3 minutes and 30 seconds.

Thus, the three lights will change simultaneously again after 9 a.m. at 9:03:30 a.m.