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Dupa o reducere de 10%,urmata de o scumpire de 5%.un obiect costa 189 lei

care a fos pretul initial?



Răspuns :

x-pretul initial

10% din x= 10/100 *x= 1/10 *x= x/10 -reducerea

x-x/10=  (10x-x)/10= 9x/10 -restul

5%  din 9x/10= 5/100 *9x/10= 1/20 *9x/10=  9x/200-scumpirea

9x/10 +9x/200= (180x+9x)/200= 189x/200-noul pret

189x/200=189

x=200*189/189

x=200