Question

Two light houses flash their lights every 20 and 30 seconds respectively. Given that they flash together at 8:00 PM. At what time will they next flash together?

Answer 1

They will flash together at;

8:01 PM

Explanation:

Here, we want to

calculate the time at which they would both flash together

What we have to do here is to calculate the lowest common multiple of 20

and 30 seconds

Mathematically, we have this as;

60 seconds

60 seconds is the same as 1 minute

So the time they will flash together is 8:01 PM