145. Solving a chemistry problem

44. (1) A weighed portion weighing 0.5000 g was dissolved in a flask with a capacity of 50.00 ml. Two samples of 20.00 ml were placed in flasks with a capacity of 50.00 ml. To one flask was added a solution containing 0.003000 g of vanadium. 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 of Ax = 0.2 Ax + St = 0.480