A metal block having an internal cavity weight 110 g in air and 80 g in water. If the density of metal is 5.5 g/cc, then the volume of cavity is:

Weight of block in air = 110 g

Weight of block in water = 80 g

Loss of weight in water = 110 - 80 = 30 g

This is equal to weight of water displaced; so volume of water displaced = 30 cc (which is the apparent volume of block)

Real volume of the material of block = $\frac{110}{5.5}= 20 \mathrm{cc}$

$\therefore \mathrm{Volume} \mathrm{of} \mathrm{cavity} = 30 \mathrm{cc}-20 \mathrm{cc} = 10 \mathrm{cc}$