Wanna some chemistry :D

Completely dissolve $15.6 g$ of mixture include $Fe, Fe_{2}O_{3}, Fe_{3}O_{4},CuO , MgO$ into $200 g$ solution of $H_{2}SO_{4}$ and $NaNO_{3}$ obtained solution $X$ .Solution $X$ contains only the sulfate salts of the metals, $Y$ gas mixture include $0,01$ mol $N_{2}O$ and $0,02$ mol $NO$ .Let $X$ react with solution $Ba(OH)_{2}$ take excess,obtained $89,15 g$ precipitate. Precipitate is filtered and calcined in air to constant volume obtained $84,386 g$ solid. Percentage concentration of solution $FeSO_{4}$ in $X$ is nearest with which answer ?