94. Solving a chemistry problem

For the spectrophotometric determination of the content of etamsylate in the tablets of the preparation, an exact weight of the powder of crushed tablets was quantitatively transferred into a 100 ml volumetric flask, 70 ml of water was added, the mixture was stirred, the volume of the solution was brought to the mark, filtered, 2 ml of the filtrate was taken, transferred to a 100 ml volumetric flask , brought the volume of the test solution to the mark with water, mixed and measured its optical density at 301 nm.
In parallel, under the same conditions, the optical density of a standard solution of etamsylate was measured.
Derive the following formula to calculate the content of X in grams of etamsylate in one tablet of the drug:
X \u003d 5000 * A (x) * c (st) b / A (st) a,
where A(X) and A(st) are the optical density of the test and standard solution, respectively, C(st) is the concentration of the standard solution, g/ml; b and a are, respectively, the average weight of one tablet and a sample of powder of crushed tablets in grams.