64. Solving a chemistry problem

2. To build a calibration graph, the following volumes of glycerin and water were mixed and their refractive indices were measured:
V(H2O), cm3 10 8 6 4 2 0
Vglycerol, cm3 0 2 4 6 8 10
n20D 1.3330 1.3627 1.3915 1.4211 1.4484 1.4740
Determine the mass fraction of glycerol in the analyzed solution if its refractive index is 1.4114 and the density of glycerol is 1.2613 g/cm3.