46. Solving a chemistry problem

168. A 1000 ml acetic acid solution contains 0.0680 g of a dissolved vitamin B2 preparation. 10 ml of this solution was taken and diluted to 100 ml with water, the optical density Ax = 0.574 of the resulting solution was measured at λ = 267 nm in a cuvette with ℓ = 1 cm. Calculate the percentage of vitamin B2 (M = 664 g) in the analyzed solution if the molar extinction coefficient is E = 32000 l mol–1 cm–1.