[tex]a) 20\% \ din \ 50= \frac{\not20}{\not100}*50= \frac{1}{\not 5} * \not 50\to 10 \\\\\\ 50-10\to \boxed{40 \hbox{ lei \ dupa \ ieftinire}} \\\\\\ b) 15\% \ din \ 50=\frac{\not 15}{\not 100}*50= \frac{3}{\not20}*\not 50= \frac{3}{2}*5 \to \ \frac{15}{2} \approx 7,5 \\\\\\ 50+7,5 \to \boxed{57,5 \ \hbox{lei dupa scumpire}}[/tex]
