The affectionate dog runs office to home

You walk one kilometre from your office to home.

As you leave the office, your pet dog also leaves the home to meet you. When the dog meets you, it licks your hand and returns home. The dog repeats the process of running from home again and again until you and the dog arrive home together.

If you walk 4 Km/hour and the dog 12 Km/hour, how far does the dog run?

Photo Adaptation / Pixabay / lepale-3791844