A clay sample was consolidated in a triaxial test chamber under an all-around confining pressure of 152 k N/m2. The sample was then loaded to failure in undrained condition by applying an additional axial stress of 193 k N/m2. A pore water pressure sensor recorded an excess pore pressure, (Δud)f = 27.6 k N/m2 at failure. Determine the undrained and drained friction angles for the soil.