You can picture a clock or a track. If you have one going forward and one backwards, they meet at the halfway point (6), and again at the full lap (12). This happens twice in a day.
If you have one going twice as fast, they only meet when the faster one laps the slower one. The two clocks would be at 3&6, 6&12, 9&6(18), 12&12(24)
Can you give me some examples, for some reason I’m finding it hard to picture
You can picture a clock or a track. If you have one going forward and one backwards, they meet at the halfway point (6), and again at the full lap (12). This happens twice in a day.
If you have one going twice as fast, they only meet when the faster one laps the slower one. The two clocks would be at 3&6, 6&12, 9&6(18), 12&12(24)