5% commission on $46,350 is:
$${\frac{{\mathtt{5}}}{{\mathtt{100}}}}{\mathtt{\,\times\,}}{\mathtt{46\,350}} = {\frac{{\mathtt{4\,635}}}{{\mathtt{2}}}} = {\mathtt{2\,317.5}}$$
Add this to $24000
$${\mathtt{24\,000}}{\mathtt{\,\small\textbf+\,}}{\mathtt{2\,317.5}} = {\mathtt{26\,317.5}}$$
$26,317.5 is less than $28,560, so the salary without commission option is better here.