A cоntinuоus beаm's flexurаl reinfоrcement must extend аt least _____ from the point where it is no longer needed to resist tension. Assume f'c = 4,000 psi, fyt = 40,000 psi, d = 30 in., w = 20.5 in., and t = 6 in. There are five No. 6 longitudinal tension bars and No. 5 stirrups at 7 in. o.c.