Question

In a series, red light blinks after every 2 seconds, green light blinks after every 6 seconds and yellow light blinks after every 10 seconds. If all three fights starts simultaneously, then after how many seconds they blink together?

Answer 1

They will blink again simultaneously when the three timings reach there least common multiple.

the least common multiple of 2, 6, and 10 is 30

so the time they blink simultaneously is after 30 seconds.