12. Solving a chemistry problem

2. To determine titanium in steel by the addition method, a sample of steel m = 0.200 g was dissolved in a volume of up to 50 ml. To the second portion of 25 ml was added 5 ml of a standard solution with a concentration of 0.050 mg/ml, 10.0 ml of the same standard solution of reagents and brought the volume to 50 ml. Cuvette l=1.0 cm Optical density of the first solution was equal to 0.32, and the second 0.56, the third solution 0.80. What is the percentage of titanium in steel?