[tex]x+y+z=56 \\ x:y=3, \ rest \ 7 \\ y:z=3, \ rest \ 3 \\ y=3z+3 \\ x=3y+7=3(3z+3)+7=9z+9+7=9z+16 \\ \Rightarrow 9z+16+3z+3+z=56 \\ 12 z+19=56 \\ 13z=56-19=37 \\ z=\frac{37}{13} \ \Rightarrow \boxed{2\frac{11}{13}}; \\ y=3z+3=3(\frac{37}{13}+\frac{13}{13})=3 \cdot \frac{50}{13}=\frac{150}{13} \\ \Rightarrow \boxed{y=11\frac{7}{13}} \\ x=3y+7=3\cdot \frac{150}{13}+\frac{91}{13}=\frac{541}{13} \\ \Rightarrow \boxed{x=41\frac{8}{13}}[/tex]
