well, they put a downpayment of 40%, that's not subject for a loan, since they put that out of their pocket, the loan will be the 60% leftover.
[tex]\begin{array}{|c|ll} \cline{1-1} \textit{a\% of b}\\ \cline{1-1} \\ \left( \cfrac{a}{100} \right)\cdot b \\\\ \cline{1-1} \end{array}~\hspace{5em}\stackrel{\textit{40\% of 280000}}{\left( \cfrac{40}{100} \right)280000}\implies 112000\leftarrow downpayment \\\\\\ 280000~~ - ~~112000\implies 168000\leftarrow \textit{mortgage loan}[/tex]
