113. Solving a chemistry problem

To determine the aluminum content, a sample of Al(NO3)3*H2O crystalline hydrate weighing 1.823 g was dissolved in water in a 100.0 ml volumetric flask. An excess of magnesium complexonate was added to an aliquot of this solution (V = 10.0 ml). 18.55 ml of 0.02503M EDTA solution was used for titration of the released Mg ions. Find the mass fraction of Al(NO3)3 in its crystalline hydrate. What titration method was used?