[tex]a + b + c + d = 3900 \\ b = a \\ c = 3a \\ d = a + b + c[/tex]
[tex]d = a + a + 3a = 5a[/tex]
[tex]inlocuind \: in \: prima \: relatie \: obtinem[/tex]
[tex]a + a + 3a +5a = 3900 \\ 10a = 3900 \\ a = 390[/tex]
[tex]b = a = 390[/tex]
[tex]c = 3a = 3 \times 39 0 = 1170[/tex]
[tex]d = 5a = 5 \times 390 = 1950[/tex]
