Question

a chunk of metal weighs 15.45 g is added to 21.27 ml of water. The water rises to 24.78ml calculate density of the metal and explain

Answer 1

Density=Mass/Volume
Mass of metal=15.45 g
Volume of metal=(23.78-21.27)ml=2.51ml=2.51cm^3
d=15.45g/2.51cm3
d=6.16g/cm^3

Answer 2

This is the Archimedes principle in action. The object must displace the water by an amount equal to its own volume (assuming it is completely submerged).