Difference in Magnitudes between two densities

[Roma19]

Homework Statement

the question is to find the difference in magnitudes between the density of water which 0.995 and density of NaCl which is 1.0499

The Attempt at a Solution

when speaking about the difference, I simply minus 1.0499 from 0.995

since magnitude means distance and displacement . I found the slopes of mass and volume of my graph which gave me the densities of both solutions

just want to know if I am on the right track

 

[nasu]

Can you post the complete and correct text? It does not make too much sense as it is.
And density of NaCl is not 1.05 but something over 2. Maybe it's about a NaCl solution?