x-pretul initial
x+18=noul pret
[tex] \frac{1}{5}*(x+18)= \frac{1}{3}*x =\ \textgreater \ \frac{x}{5} + \frac{18}{5}= \frac{x}{3}=\ \textgreater \ \frac{x}{3}- \frac{x}{5}= \frac{18}{5}=\ \textgreater \ \\ \frac{5x-3x}{15}= \frac{18}{5}=\ \textgreater \ \frac{2x}{15}= \frac{18}{5}=\ \textgreater \ 2x= \frac{15*18}{5}=\ \textgreater \ 2x=18*3=\ \textgreater \ \\ x=54:2 =\ \textgreater \ x=27 vechiul. pret =\ \textgreater \ 27+18=45 actualul. pret [/tex]