1). [tex]x=pretul\;initial\;\\
\Rightarrow\;x\cdot\frac{112}{100}\frac{90}{100}=3600\,lei\;\;x=\frac{3600\cdot100\cdot100}{112\cdot90}\approx3571,43\,lei[/tex]
2). [tex]\frac{90-x}{180-x}=\frac{1}{3}\;\Leftrightarrow\;270-3x=180-x\rightarrow\;m(\widehat{x})=95^0[/tex]