Volume of the object is equal to the volume of water displaced by it = 15 ml
The mass of the object is given as 12 g
Density of a substance is the amount of that substance per unit volume
i.e. Density = Mass/volume = 12 g/15 ml = 0.8 g/ml
The density of water is 1 g/ml. If the density of an object exceeds that of water, then it will sink otherwise it will float.
Here, the density of the object (0.8 g/ml) is lower than that of water, hence it will float if placed in water.
