Răspuns :
Notam cu x numarul de baietii si cu y numarul de fete.
x+y=840
y= x·2 ( 2x )
x+y=840⇒x+x·2=840⇒
x+2x=840⇒3x=840⇒
x=840:3⇒x=280 (280 baieti)
y= x·2⇒y=280·2⇒y=560 (560 fete)
Verificare:
540+280=840
x+y=840
y= x·2 ( 2x )
x+y=840⇒x+x·2=840⇒
x+2x=840⇒3x=840⇒
x=840:3⇒x=280 (280 baieti)
y= x·2⇒y=280·2⇒y=560 (560 fete)
Verificare:
540+280=840