A fresh 5.2 cm long sandstone rock core with an outside diameter of 6.3cm and inside diameter of 1.2cm was flooded with water until no more oil was recovered, leaving a residual oil saturation of 16% in the core. The core still held 4% of gas saturation in it. Thereafter, the core was radially flooded with 3 liters of brine of 0.95 mPa.s viscosity for 315 minutes at an inlet pressure of 40 psig and outlet pressure of 14.7 psia. Compute the effective permeability to the brine at 80% saturation in Darcy