Problem $2.$ Design a composite slab on a simply supported precast reinforced concrete beam span of $24ft.$ The spacing of beams is $8ft$ center$-$to$-$center. The cast$-$in$-$place slab is $4$ in$.$ thick and the live load is $200$ psf$.$ Use $f_c{?}_c(slab)=3000$ psi, $f_c{?}_c$ precast beam