Question

a cabra e o cavalo valem r$240,00 , a cabra e a vaca valem r$270,00 ,o cavalo e a vaca valem r$290,00.Qual o preço de cada animal?

Answer 1

x + y = 240 --> y = 240-x
x + z = 270 --> z = 270-x
y + z = 290

240-x + 270-x = 290
-2x = 290-240-270
-2x = 290-510
-2x = -220 *(-1)
2x = 220
x = 220/2
x = 110

y = 240-110
y = 130

z = 270-110
z = 160

cabra: R$ 110,00
vaca: R$ 160,00
cavalo: R$ 130,00