Question

Two of the lights at the local stadium are flickering. They both just flickered at the same time. One of the lights flickers every 7 seconds and the other light flickers every 8 seconds. How many seconds until both lights will flicker at the same time agaln?

Answer 1

if what ive done is correct they will never flicker again together

Answer 2

Good morning.

We will use the Least common multiple between 7 and 8. We can make this because the flicks make a sequence in time, and when both times are equal, we have both lights flickering together.

We must factor 7 and 8:

7 = 7 (It is a prime number)

8 = 2³


In order to find the least common multiple, we take the numbers in the factors of 7 and 8 that have the highest exponents. For example, if a number has a factor of 2² and other number the factor 2³, we will take 2³.

We take 7 and 2³.


Now we multiply and find the l.c.m.:

l.c.m. = 7 . 2³ = 7 . 8

l.c.m = 56.


Therefore, after 56 seconds, both lights will flicker at the same time.