For this type of problem the speed we need to be concerned with is the relative speed between the Klansman and the Negro.
7 km/h - 5 km/h = 2 km/h
The Klansman is closing the distance between the two of them at a rate of 2 km/h.
Speed = distance / time
2 km/h = 0.06 km / time
Time = 0.06 km / (2 km/h)
Time = 0.03 h
From there you can convert to minutes or seconds if you want to make the answer more relatable:
Time = 1.8 min
Time = 108 sec
As I was doing this I noticed that the speed I assigned the negro was average human walking speed. Maybe I should have specified that the negro was carrying 6 buckets of KFC to make it more believable.
For this type of problem the speed we need to be concerned with is the relative speed between the Klansman and the Negro.
7 km/h - 5 km/h = 2 km/h
The Klansman is closing the distance between the two of them at a rate of 2 km/h.
Speed = distance / time
2 km/h = 0.06 km / time
Time = 0.06 km / (2 km/h)
Time = 0.03 h
From there you can convert to minutes or seconds if you want to make the answer more relatable:
Time = 1.8 min
Time = 108 sec
As I was doing this I noticed that the speed I assigned the negro was average human walking speed. Maybe I should have specified that the negro was carrying 6 buckets of KFC to make it more believable.