80. Solving a chemistry problem

93. The declared content of cortisone acetate in its preparation is at least 97.0%. To determine the actual content of cortisone acetate in a sample of the preparation, an alcoholic solution of the preparation was prepared with a mass concentration of the latter of 0.001% and its optical density A(X) was measured on a spectrophotometer at a wavelength of λ = 238 nm. In the same cuvette and at the same wavelength, the optical density A(st) of an alcoholic solution of a cortisone acetate standard sample with an accurately known concentration of cortisone acetate equal to 0.001% was measured. Calculate the percentage of cortisone acetate in the preparation if the ratio of the optical densities of the solutions is A(st)/A(X) = 1.015.