Question

Daca$\frac{5x}{6y} =0,3125$, atunci calculati valoarea raportului $\frac{19x-7y}{5x+3y}$ .

Answer 1

$\dfrac xy=\dfrac{3125}{10000}\cdot\dfrac 65=\dfrac38\Rightarrow x=\dfrac{3y}{8}$

In locuim aceasta valoare in fractia pe care trebuie sa o calculam

$\dfrac{19x-7y}{5x+3y}=\dfrac{19\cdot\dfrac{3y}{8}-7y}{5\cdot\dfrac{3y}{8}+3y}=\dfrac{57y-56y}{15y+24y}=\dfrac{1}{39}$