A light flashes every 2 minutes a, second light flashes every 7 minutes, and a third light flashes e

A light flashes every 2 minutes a, second light flashes every 7 minutes, and a third light flashes every 8 minutes. If all lights flash together at 8 P.M., what is the next time of day they will all flash together

We use our least common multiple calculator to see when the 3 numbers have a common multiple:
LCM of (2, , 8) = 56 minutes

So this means we add 56 minutes to 8:00 P.M. and we get 8:56 P.M.