Question

o gospodina pune in camara 11l de sirop cu capsuni in sticle de 500ml sin75 cl. cate sticle de 500 ml si cate de 75 cl avea gospodina, daca in total sunt 18 sticle?

Answer 1

11 l = 11000 ml
75 cl = 750 ml

a- nr de sticle de 500 ml
b- nr de sticle de 750 ml

a+b=18 (sunt 18 sticle in total)  inmultim cu 2 => 2a+2b=36  (1)
a*500+b*750=11000 (impartim la 250) => 2a+3b=44  (2)

(2)-(1) => b=8 (8 sticle de 750 ml)

Inlocuim b in ecuatia: a+b=18 => a+8=18 => a=10 (10 sticle de 500 ml)

Answer 2

11 l = 11000 ml
75 cl= 750 ml

x= nr de sticle de 500 ml
y= nr de sticle de 750 ml

x+y= 18⇒ x=18-y
500x + 750y=11000 /:50 ⇒ 10x + 15y = 220
⇒10 (18-y) + 15y=220
180 - 10y +15y=220
5y= 220-180
5y=40
y=40:5
y= 8 sticle de 750 ml
x=18-8=10 sticle de 500 ml