010. Solving a chemistry problem

1. A sample of steel weighing 0.9580 g was dissolved in a flask with a capacity of 50.00 ml. Two 20.00 ml samples were placed in 50.00 ml flasks. A solution containing 0.003000 g of vanadium was added to one flask. Hydrogen peroxide was added to both flasks and brought to the mark with water. Calculate the mass fraction (%) of vanadium in steel if the following optical densities were obtained during photometry of solutions: Dx = 0.280 and Dx + st = 0.560. When deciding to use the graphical method.