We know that density = 5g/cm^3 and mass = 50g, then we have:
5g/cm^3 = 50g/V
V = 50g/5g/cm^3 = 10cm^3
Then, when we introduce it in a cylinder with 50cm^3 of water, this is heavier than water (the density of the water is 1g/cm^3) it will sink, and the complete volume will be equal to the volume of the water plus the volume of the object: