49. Solving a chemistry problem

2. In the preparation "Phenoxymethylpenicillin", absorbing impurities are determined as follows: about 0.1 g of the drug (exact weight) is dissolved in 4 ml of 5% sodium bicarbonate solution, diluted with water in a volumetric flask with a capacity of 500 ml to the mark and the optical density is determined (A) at wavelengths of 268 and 274 nm in a cuvette with a layer thickness of 10 mm. The reference solution is 4 ml of a 5% sodium bicarbonate solution, diluted with water to 500 ml.
Ratio А268/А274=1.22
The optical density of the solution at a wavelength of 268 nm is 0.645. Calculate what will be the optical density at a wavelength of 274 nm.