A 1.2504 g sample of a reaction product containing acetylsalicyclic acid (ASA) was dissoloved in 100 mL of 0.05 M sulfuric acid and diluted by a factor of 100 with deionized water. An absorption measurement of this ASA solution at 275 nm in a UV-vis spectrometer with a 1.00 cm cell was 0.78. The solvent had an absorbance of 0.01 at 275 nm. Measurement of a 4.05x10-4 M ASA standard solution at 275 nm was 0.579.
How do I calculate the concentration of ASA in the solution?