[tex] \frac{a+b+c}{3} =2,4 =\ \textgreater \ a+b+c=2,4*3=\ \textgreater \ a+b+c=7,2 \\ \frac{a+b}{2} =3,15 =\ \textgreater \ a+b=3,15*2=\ \textgreater \ a+b=6,3 \\ a=2b \\ 2b+b=6,3=\ \textgreater \ b=6,3:3=\ \textgreater \ b=2,1 \\ a=6,3-2,1=\ \textgreater \ a=4,2 \\ 6,3+c=7,2=\ \textgreater \ c=7,2-6,3=\ \textgreater \ c=0,9[/tex]