Problema Solution
A red light flashes 3 times per minute,green light flashes 4 times per minute and yellow light flashes 6 times per minute at regular intervals.If all three lights start flashing at the same time,how many times do they flash together in each 75 minutes?
Answer provided by our tutors
The least common factor for 3, 4 and 6 is 12.
This means that every 4 minutes he lights will flash at the same time.
Since 75 : 4 = 18.5 the light will flash together 18 + 1 = 19 times (counting the start flash at the 0 minute).