Question

Daca x si y suntdirect proportionale cu 4 si 5 aflați cat la suta reprezintă x din y?

Answer 1

$x;y \ \ \ dp. \ \ \ cu \ \ \ 4;5 \\\\ \frac{x}{4}=\frac{y}{5}=k \\\\ x=4k \\ y=5k \\\\ x= p\% \ din \ y \\\\ x=\frac{p}{100}*y \\\\ 4k=\frac{p}{\not100}*\not5k \\\\ 4k=\frac{p*k}{20} \\\\ p=\frac{\not4k*20}{\notk}\\\\ p=4*20 \\\\ \boxed{p=80\%}$

Answer 2

 [tex]avem:\;\frac{x}{4}=\frac{y}{5}\;\;folosand\;\;proprietatile\;proportiilor\;derivate\;cu\;acelasi\,termeni\\
(schimbam\,miezii\,intre\,ei \;!!!)\\
\rightarrow\;\;\frac{x}{y}=\frac{^{20)}4\,\,}{\,\,\,\,5\,\,}=80/100[/tex]