Question

3. Scout is conducting a research project on traffic patterns

in her town. She realizes that at 6:00 AM each morning, the
traffic lights reset and function on a pattern. The traffic light
on Main St. turns red every 7 minutes. The traffic light on Elm
St. turns red every 15 minutes. At what time will both lights be
red at the same time?

Answer 1

7:45

Explanation:

Since they both turn red at differnt times, you have to find a multiple to find the time they will be both on

Main St: 7, 14, 21, 28, 35, 42, 49, 56, 63, 70, 77, 84, 91, 98, 105

Elm St. 15, 30, 45, 60, 75, 90, 105

They will both turn on 105 minutes or 1 hour and 45 minutes from 6

6 + 1 hr 45 min = 7:45