Given data
*The given time is t = 1 min
*Person walks the distance towards north is 20.0 m
*Person walks the distance towards west is 8.0 m
*Person walks the distance towrds south is 20.0 m
The diagram is given below
As the person firstly walks 20.0 m north, and then 8.0 m west, and then travels 20.0 m south. Hence, the displacement traveled by the person is s = 8.0 m.
The formula for the magnitude of the velocity is given as

Substitute the values in the above expression as

Hence, the magnitude of the velocity of the person is v = 8.0 m/min
The total distance traveled by the person is calculated as

Hence, the total distance traveled by the person is d = 48.0 m
The formula for the speed is given as

Substitute the known values in the above expression as

Hence, the speed is u = 48.0 m/min