Question

UN ATLAS COSTA 50 DE LEI , CAT AR COSTA ATLASUL DACA:
A)S-AR IEFTINI CU 20 %
B)S-AR SCUMPI CU 15 % 
URGENT VA ROG EU CAT MAI REPEDE

Answer 1

a)50-20/100*50= 50-10=40 lei b)50+15/100*50= 50+7,5=57,5 lei

Answer 2

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