Assume that the $300-mm$ width is increased to $350mm$ in the image. The reinforced concrete beam shown is subjected to a positive bending moment of $175kN*m.$ Knowing that the modulus of elasticity is $25$ GPa for the concrete and $200$ GPa for the steel, determine

$($a$)$ the stress in the steel: $$ MPa

$($b$)$ the maximum stress in the concrete: $$ MPa