What is the use of density in the calculation of percentage by mass?

First, the direct method requires recording the total mass of solution, and then evaporating off the solvent. The solid left behind is the solute, which is then weighed and used to calculate mass percent. Density can also be used to determine the mass percent of an unknown concentration.

in my opinion:)

it's filtration, but this is an assumption so my apologies if i got this