The iceberg floats immersed in water by 4/5 of its volume. Is there an air cavity inside the iceberg or is it solid?

The iceberg floats immersed in water by 4/5 of its volume. Is there an air cavity inside the iceberg or is it solid? The density of ice is 900 kg / m (3). The density of water is 1000 kg / m (3).

yes, there is a cavity in the iceberg since the volume of the submerged part of the body is equal to the ratio of the density of the body to the density of the liquid
Divide 900kg / m3 by 1000kg / m3 = 9/10
that is, it must be submerged by 9/10 of its volume
and it is loaded by 8/10, that is, 4/5 means its density is 800 kg / m3
established experimentally