[tex]x=pretul\,initial\;si \;p= reducerile\,consecutive\;;\\
(x\cdot\frac{100-p}{100})\cdot\frac{100-p}{100}=x\cdot\frac{36}{100}\;\;|_{\cdot\frac{100}{x}}\\
(100-p)\cdot\frac{(100-p)}{100}=36\\
(100-p)^2=3600\;\rightarrow\;100-p=60\,\rightarrow\;p=40^o/_o[/tex]