Question

Dupa 2 cresteri succesive de pret, prima cu 10% si a doua cu 15%,un calculator costa 1265 de lei. Aflati pretul initial al acestuia.

Answer 1

notez cu x pretul initial

dupa cresterea de 10% pretul devine: $x+\frac{10}{100}*x=x+\frac{x}{10}  =\frac{10x+x}{10} =\frac{11x}{10}$

dupa cresterea de 15% pretul devine:[tex]\frac{11x}{10}+\frac{15}{100}*\frac{11x}{10}=\frac{11x}{10} +\frac{3*11x}{20*10} =\frac{20*11x+33x}{20*10}=\frac{220x+33x}{200}  =\frac{253x}{200} =1265 =>x=\frac{200*1265}{253}=200*5=1000 lei[/tex]

Answer 2

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