29. Solving a chemistry problem

2. In the photometric analysis of a concentrated solution of potassium permanganate by differential photometry, a standard solution of KMnO4 with a concentration of 0.060 mo/ml was chosen as a reference solution. When constructing a calibration graph at λ=530 nm, the following results were obtained:
С(KMnO4), mg/ml 0.020 0.040 0.060 0.080 0.100
Aotn -0.60 -0.30 0 0.30 0.60
Construct a calibration graph and determine the concentration of KMnO4 in the solution if the measured relative optical density (Arel) of this solution is 0.43. Calculate the mass of KMnO4 in 250 ml of the analyzed solution.