The speed of 4 km/h means that you can cover a distance of 4 kilometers in one hour. To calculate the time it would take to walk 1 kilometer at this speed, you can use the formula:
Time = Distance / Speed
Plugging in the values:
Time = 1 km / 4 km/h = 0.25 hours
Since there are 60 minutes in an hour, 0.25 hours is equal to 15 minutes. Therefore, it would take approximately 15 minutes to walk 1 kilometer at a speed of 4 km/h.