Traffic light problem

The traffic light problems are a type of mathematical problems involving several distant traffic lights out of phase and a car moving at a constant speed.

 Example 
Imagine a 1-meter road, with a traffic light in the background that changes from red to green every 10 seconds. If the car travels at 1 meter per second, we can guarantee that unless it starts in second 9 of being green, it will always have to wait less than 10 seconds.

 References 

Category:Traffic signs