x-carti de 10 lei
y-carti de 12 lei
(scrii sub forma de sistem)
10x+12y=260(echivalent)10x+12y=260(echival.)10(23-y)+12y=260(echival.)
x+y=23 x=23-y x=23-y
230-10y+12y=260(echival.)2y=30 (echival.)y=15 (echival.)y=15
x=23-y x=23-y x=23-15 x=8
Deci,sunt 8 carti de 10 lei si 15 carti de 12 lei.
Verificam :
8x10=80(lei) 15+8=23 (carti)
15x12= 180(lei)
80+180=260(lei)