The commission was 20,000 which was 2% of the total value.
Let the total value be x. Then,
[tex]\begin{gathered} 2\text{ \%}=\frac{20000}{x}\times100\text{ \%} \\ x=\frac{20000}{2}\times100 \\ x=1000000 \end{gathered}[/tex]Hence the value of flat was 1000000.