Question

5m stofa si 5m catifea costa 315. 10m stofa si 7m catifea costa 525 lei.Afla cat costa fiecare metru.

Answer 1

O sa notez "1m stofa" cu "x" si "1m catifea" cu "y".
5x + 5y = 315
10x + 7y = 525
Din prima ecuatie rezulta: 5x=315-5y
Inlocuind in a doua ecuatie, avem:
2(315-5y) + 7y = 525 ⇔ 630-10y+7y=525 ⇔ -3y=525-630 ⇔ -3y=-105 ⇔ y= 35. Deci, 1m catifea costa 35.
5x + 175 = 315 ⇔ 5x = 140 ⇔ x = 28
In concluzie, 1m stofa costa 28 si 1m catifea costa 35.