so, Kemar sold it for $20000, and that was bumped up in price by 25% then.
now, if the cost was say "x", that is the 100%, we know he sold it for 25% more than that, namely the 125%, so if 20000 is the 125%, what is "x", the 100%?
[tex]\bf \begin{array}{ccll}
amount&\%\\
\text{\textemdash\textemdash\textemdash}&\text{\textemdash\textemdash\textemdash}\\
20000&125\\
x&100
\end{array}\implies \cfrac{20000}{x}=\cfrac{125}{100}\implies \cfrac{20000\cdot 100}{125}=x[/tex]
