111. Solving a chemistry problem

To determine the content of cadmium in an alloy by the method of additions, weigh an alloy weighing 2.2940. Dissolved and after appropriate treatment, the volume of the solution was brought to 250 ml. To remove the polarogram, 18 ml of this solution were taken. The wave height was 19.5 mm. After the addition of 0.0430 N CdSO4 Vst = 5.0 ml, the wave height increased to 28 mm. Determine the percentage of cadmium in the alloy