Question

La un magazin alimentar s-au vandut intr-o zi 3/5 din intreaga cantitate de zahar existenta,iar a doua zi 3/5 din rest si au mai ramas 148kg de zahar.Ce cantitiate de zahar a existat in magazin ?

Answer 1

$\boxed{\bold{Fie \ x \ cantitatea \ de \ zahar \ ce \ era \ deodata \ la \ magazin;}} \\ \bold{Prima \ zi}=x\cdot \frac{3}{5} \\ \bold{A \ doua \ zi=} \frac{3}{5} \cdot (x-x \cdot \frac{3}{5}) \\ x \cdot \frac{3}{5}+\frac{3}{5}(x-x\cdot\frac{3}{5})+148=x \\ \frac{3 \cdot x}{5}+148+\frac{3}{5} \cdot(x-\frac{3 \cdot x}{5})=x \\ 3 \cdot x+740+5 \cdot \frac{3}{5}\cdot \frac{5x-3x}{5}=5x \\ 3x+740+\frac{5 \cdot 3 \cdot(5x-3x)}{5 \cdot 5}=5x \\ 75x+18 500+5 \cdot 3\cdot (5x-3x)=12 \\ 75x+18 500+15 \cdot 2x=125x$
$75x+18500+30x=125x \\ 105x+18500=125x \\ 18500=125x-105x \\ 20x=18500 \\ x=\frac{18500}{20} \\ \Rightarrow \boxed{\bold{x=925 \ kg}}$