Question

problema 9

DAU COROANA

Answer 1

P=2L+2l=384; L=lungimea; l=latimea.
Scriem conditiile puse de problema sub forma unei relatii matematice:
(2/3)×l+25=(1/2)×L-1
2L+2l=568 ⇒ 2(L+l)=384 ⇒L+l=384:2 ⇒L+l=192⇒ L=192-l
Inlocuim:
(2/3)×l+25=(1/2)×(192-l)-1
2l/3+25=96-l/2-1
2l/3+l/2=96-25-1
4l/6+3l/6=70
7l/6=70
7l=70×6
7l=420
l=420:7
l=60m
L=192-l
L=192-60
L=132m.
Proba:
P=2L+2l=2×132+2×60=264+120=384 Corect.
2/3 din l=60×2/3=40
40+25=65.
1/2 din L =132:2=66
66-1=65. Corect!