[tex]\text{Notam pretul initial al obiectului cu x.}\\
x-\dfrac{15}{100}\cdot x-\dfrac{20}{100}\left(x-\dfrac{15}{100}\cdot x\right)=136\\
\\
\dfrac{85}{100}\cdot x-\dfrac{1}{5}\cdot \dfrac{85}{100}\cdot x=136\\
\\
\dfrac{85}{100}\cdot x-\dfrac{17}{100}\cdot x=136 |\cdot 100\\
\\
85x-17x=13600\\
68x=13\\
\boxed{x=200\ lei}[/tex]