Răspuns:
Explicație pas cu pas:
Cristina = a, Ege = b , Alina = c şi Arzu = d
a+b+c+d = 252
a-20 = x₁
b-20 = x₂
c-20 = x₃
d+60 = x₄
x₁ = x₁ ; x₂ = x₁+2 ; x₃ = x₁+4 ; x₄ = x₁+6
x₁+x₁+2+x₁+4+x₁+6 = 252
4x₁+12 = 252 =>
4x₁ = 240 => x₁ = 240:4 =>
x₁ = 60 ; x₂ = 62 ; x₃ = 64 ; x₄ = 66
a = 60+20 => Cristina a cules 80 mere
b = 62+20 => Ege a cules 82 mere
c = 64 + 20 => Alina a cules 84 mere
d = 66-60 = > Arzu a cules 6 mere
80+82+84+6 = 252
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