38. Solving a chemistry problem

192. During the fluorimetric determination of uranium, a standard solution was prepared containing 0.40 μg of a substance in 5.00 ml of a solution, and the fluorescence intensity of this solution was measured I = 100. The analyzed solution was quantitatively transferred into a 100 ml volumetric flask, the volume of the solution was brought to the mark with water and measured the fluorescence intensity under the same conditions: I = 55. Calculate the mass of uranium in the analyzed solution.