Given information:

A mass of dry rock (M) is 2,450 kg.

The volume of dry rock (V) is 0.925 m3.

The specific gravity of the rock mineral (Gs) is 2.80.

Consider the density of water (ρw) is 1,000 kg/m3.

Calculation:

Determine the dry density of rock minerals ρd.

ρd=MV=2,4500.925=2,648.6 kg/m3

Determine the void ratio (e) using the relation.

ρd=Gsρw1+e2,648.6=2.80×1,0001+ee=2.80×1,0002,648.6−1e=0.0571

Determine the porosity (n) using the relation.

n=e1+e=0.05711+0.0571=0.054

Therefore, the porosity of the rock is 0.054_.