If you have 2 objects of diferrent densities and you want them to have equal masses,what ratio of the volume to each other

The answer I think the object with the greater density must have low volume compared to the other with small density

Use

mass = ρ1v1 = ρ2v2
v1/v2=ρ2/ρ1
or
v1:v2 = ρ2:ρ1

v1,v2 volumes
ρ1, ρ2 densities