J.R. S. answered 02/05/21
Ph.D. University Professor with 10+ years Tutoring Experience
Density = grams / unit volume
So we need to know the grams and the volume of the object of interest.
We are given the grams, so we now need to find the volume of the magnet and the bolt.
Look up Archimedes Principle to get a better idea of how this works.
The volume of water that is displaced by the object, is taken as the volume of that object.
Magnet: Object volume = 2.00 ml
Density = 7.93 g / 2.00 ml = 3.97 g/ml
Do the bolt the same way