Question

A pencil has a density of 8.75g\ml. it has a mass of 3.5grams what is the volume?

Answer 1

I think that to find the volume , you just need to do:
3.5 grams *1ml/8.75 g =0.4 ml 
so you do it the way that the gram will be cancelled

Answer 2

Density = Mass/Volume
p = M/V (where p is density)

8.75 = 3.5/V
V = 8.75/3.5 = 2.5 
The volume of the pencil is 2.5 grams.