As a result of dissolution of 160 g of sulfuric anhydride in a 24.5% solution of sulfuric acid, the concentration

As a result of dissolution of 160 g of sulfuric anhydride in a 24.5% solution of sulfuric acid, the concentration of the latter increased to 60%. How much sulfuric acid solution was used?

Find the number of moles of sulfuric anhydride and acid:
n (SO3) = m / M = 160/80 = 2 mol.
n (H2SO4) = 1n (SO3) = 2 mol.
The theoretical mass of sulfuric acid:
m (H2SO4) = n * M = 2 * 98 = 196 g.
Let us find the mass of the sulfuric acid solution in which sulfuric anhydride was dissolved, we denote it by x, then the mass of sulfuric acid in it = 0.245x.
Let us express the mass fraction of the resulting solution in the form of an equation:
0.6 = 0.245x + 196 / x + 160, hence x = 101.4 g.