If the elasticity of demand for salt is zero and a household demands 2 kg of salt in a month at rs.5 per kg, how much will it demand at rs.7.5 per kg.

Zero elasticity of Demand or inelastic demand refers to same demand at all prices. It means quantity demanded for a commodity is not at all affected by a change in its price. Its demand curve is a vertical line parallel to Y-Axis.

Hence, the quantity demanded for salt will remain same.