Determine the cаsting-pоsitiоn mоdificаtion fаctor, ψt, for a rectangular beam with b = 17 in. and d = 21 in., five galvanized No. 7 Grade 60 tension-reinforcement bars placed in the bottom of the beam, and No. 3 Grade 40 stirrups located every 8 in. along the span. Assume 7,000-psi lightweight concrete and a clear cover of 1.75 in.