A slab spans $4\mathrm{.}5m$ from $\frac{c}{c}$ of end supports. Design the slab to carry a live load of $3\mathrm{.}0k\frac{N}{m^2}$ plus floor finishes and ceiling loads of $1\mathrm{.}0k\frac{N}{m^2}.$ The characteristic material strengths are fcu$=30\frac{N}{m}{m}^2$ and $.$ Basic span$-$effective depth ratio $=20.$