Rectangular sections, $\backslash (40\backslash$mathrm$\{$~mm$\}\backslash$times $10\backslash$mathrm$\{$~mm$\}\backslash ),$ of steel and brass from the composite section, $\backslash (40\backslash$mathrm$\{$~mm$\}\backslash$times $20\backslash )$ mm $,$ of a beam shown below. The brass is to lie beneath the steel when the beam is simply supported over a length of $750$ mm $.$ Calculate the maximum central concentrated load that may be applied, given allowable stresses for the brass and steel of $70$ and $105$ MPa respectively, when the materials $($i$)$ each bend independently and $($ii$)$ are bonded along the interface. Take E $=84$ GPa for brass and $\backslash (\backslash$mathrm$\{$E$\}=207\backslash$mathrm$\{$GPa$\}\backslash )$ for steel