Question

if block a has a greater mass than block b, what can be said of the relative densities of the two metals? (assume that both blocks are solid.)
the material of the block a has greater density than the material of the block b.
the material of the block b has greater density than the material of the block a.
the densities of the materials of these two blocks are equal.
nothing can be said definitely about the densities of the blocks.

Explanation:

Density is defined as mass per unit volume ($
ho=\frac{m}{V}$). Just knowing that block A has a greater mass than block B is not enough because we don't know the volumes of the two blocks. A large - mass object can have a low density if its volume is very large, and a small - mass object can have a high density if its volume is very small.

Answer:

Nothing can be said definitely about the densities of the blocks.