Explanation:
According to table,
Mass of iron model (
) is given as 6.66 kg
Density of gold, (
) = 19320
unit
Density of iron, (
) = 7850
unit
Now, new model shape = old model shape
So, volume or iron model = volume of gold model
That is,
As relation between density and volume is as follows.
Volume = 
Therefore,

or,
= 16.4 kg
Thus, we can conclude that mass of gold model,
is 16.4 kg.