Question

Perimetrul unui dreptunghi e de 1 km .Aflati latimea si lungimea stiind ca :un sfert din lungime e cu 20 mai mare decat a treia parte din latime .

Answer 1

P=1km=1000m  P=2*(L+l) 1000=2(L+l)    L+l=1000:2=500m
L/4=l/3+20  L=(l/3+20)*4=4l/3+80
L+l=500m
4l/3+80+l=500m
7l/3=500-80=420m
7l=420*3=1260m
l=1260:7=180m
L=500-180=320m
proba: 2(180+320)=2*500=1000m
320/4=80
180/3=60 si 60+20=80 deci corect