To calculate the time it will take to cover a distance at a certain speed, you can use the formula:
Time = Distance / Speed
Given that you are traveling at 20 km per hour and want to cover a distance of 50 km, you can plug in the values:
Time = 50 km / 20 km per hour
Time = 2.5 hours
So, it will take approximately 2.5 hours to cover a distance of 50 km at a speed of 20 km per hour.