Question

Aba,Irinasi Teodorasunt colegede clasă.Ele colectioneaza tumbre.Ana si Irina au impreuna780de timbre,Ana ai Teodora au impreuna 960de timbre,iar Irina ai Teodora au impreuna 820 de timbre
Cate timbre are fiecare fetita

Answer 1

A + I = 780
A + T = 960
I + T = 820
2A + 2 I + 2T = 780 + 960 + 820 = 2560
2 ( A + I + T ) = 2560
 A + I + T = 2560 : 2
A + I + T = 1280
780 + T = 1280
T = 1280 - 780
T = 500 ( ARE TEODORA)
A + T = 960
A + 500 = 960
A = 960 - 500
A = 460 ( ARE ANA)
A + I = 780
460 + I = 780
I = 780 - 460
I = 320 ( ARE IRINA)
VERIFICAM
320 + 460 + 500 = 1280

Answer 2

Notam a=Aba, i=Irina si t=Teodora
a+i=780
a+t=960
i+t=820
2a+2t+2i=780+960+820
2(a+t+i)=2560
a+t+i=1280
a=1280-820
a=460 timbre
i=780-460
i=320
t=820-320
t=500