(N/A) The person was making use of the $Archimedes'$ principle,which relates the buoyant force on an object to the weight of the fluid displaced by it. This allows for the determination of the density of the object.
$(b)$ The density of the gold is determined using the relation:
$\text{Relative Density} = \frac{\text{Weight of the body in air}}{\text{Loss of weight in water}}$
Since the density of water is $1 \text{ g/cm}^3$,the relative density is numerically equal to the density of the gold in $\text{g/cm}^3$.
$(c)$ The values Kanchan imbibed include:
$(i)$ Awareness regarding the quality of products.
$(ii)$ Scientific temper and critical thinking.
$(iii)$ Seeking evidence-based verification for claims.