111. Solving a chemistry problem

The molar light absorption coefficient ε at 550 nm for Cr(VI) is 0, and for Mn(VII) it is 21000, at 430 nm ε Cr(VI)=220, and for Mn(VII)=500. Calculate the concentration of chromium (VI) and manganese (VII) in a sulfuric acid solution if the optical density of this solution at 430 nm is 0.42, and at 550 nm it is 0.71 in a cuvette with a layer thickness of 2 cm.