35. Solving a chemistry problem

100. The amount of zinc in the alloy was measured using the polarographic method. A sample of the alloy weighing 0.8120 g was transferred to a 200 ml volumetric flask. Then 50.0 ml of the resulting solution was placed in a 100 ml volumetric flask and made up to the mark with water. When polarographing this solution, a wave with a height of 36 mm was obtained. To polarograph a standard solution, 5.0 ml of a solution containing 0.085 mg/ml Zn was placed in a 100 ml volumetric flask and the solution was diluted to the mark with water. For this solution, a wave with a height of 25 mm was obtained. Calculate the mass fraction of zinc in the alloy.