81. Solving a chemistry problem

3. To construct a calibration graph of acetylsalicylic acid, its standard solutions with concentrations of 0.10, 0.20, 0.30, 0.40 and 0.50 mg/l were taken. Chromatographic analysis of these samples showed that the peak areas of the standard solutions would be equal to 10, 21, 32, 41 and 49 mm2, respectively. Then a sample of unknown concentration was taken, the peak area of ​​which was 37 mm2. Determine the concentration of acetylsalicylic acid in the unknown sample.