[tex]\text{p.i - pret initial} \\ \text{p.f - pret final } \\\text{p - procent}\\ \\ \boxed{ p.i+ \frac{p}{100}\cdot p.i = pf} \\ \text{Formula de scumpire} \\ \\ 100+ \frac{20}{100}\cdot 100=pf \\ 100+20=\boxed{120} \\ \\ \text{Deci,pretul final este de 120 de lei } \\ \\ \\ ------------- \\ \boxed{ p.i+ \frac{p}{100}\cdot p.i = pf} \\ \text{Formula de scumpire} \\ \\ \boxed{ p.i- \frac{p}{100}\cdot p.i = pf} \\ \text{Formula de ieftinire}[/tex]
