Velocity (v) is a vector quantity that includes the magnitude and the direction. The magnitude of the quantity is the quotient obtained in dividing the distance (d) by the time (t).
v = d / t
Substituting the known values,
v = (5 km) / (25 minutes) = (5000 m) / (1500 s) =3.33 m/s
Therefore, Walt's velocity is 3.33 m/s due east.