Question

Numerele x ,y , z sunt direct proportionale cu 2,6,20 cat la % din z reprezinta x+y

Answer 1

$\frac{x}{2} = \frac{y}{6}= \frac{z}{20} = \frac{x+y}{8} =k \\ z=20k \\ x+y=8k \\ \frac{p}{100} \cdot 20k=8k \\ \frac{p}{5} =8 \\ p=40$
p%=40%

Answer 2

x/2=y/6=z/20=k
⇒x/2=k⇒x=2k;
⇒y/6=k⇒y=6k;
⇒z/20=k⇒z=20k;
⇒a/100 ·z=x+y
⇒a/100 ·20k=2k+6k=8k
⇒a/100=8k/20k
⇒a/100=8/20
⇒a/100=0,4
⇒a=40[la suta-reprezinta x+y din z];