A simply supported prestressed concrete beam of c/s 150 mm × 250 mm is subjected to a superimposed load of 5 kN/m over a span of 5 m. If the prestressing force of 750 kN is applied through parabolic cable with eccentricity of 50 mm at centre and zero eccentricity at support, then what will be the extreme fibre stress at bottom fibre at end support? (Neglect the self-weight)