[tex]\it \left.\begin{aligned} \it c=2a\ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \ \rule{1}{0.1}\\ \\ \it a<c\ cu\ 96 \Rightarrow c>a\ cu\ 96 \Rightarrow c=a+96 \end{aligned}\right\} \Rightarrow a=96,\ \ c=2\cdot96=192\\ \\ \\ a=3b \Rightarrow 96=3b|_{:3} \Rightarrow b=32\\ \\ \\ a+b+c=96+192+32=320[/tex]
