A hydraulic oil is flowing in a drawn steel hydraulic tube with an OD of 50 mm and a wall thickness of 1.5 mm. A pressure drop of 68 kPa is observed between two points in the tube 30 m apart. The oil has a specific gravity of 0.90 and a dynamic viscosity of 3.0 × 10⁻³ Pa·s. Calculate the velocity of flow of the oil.