What is perfect inelastic demand?

Answer 1

In economic theory, a perfect inelastic demand is a demand for some product that cannot be reduced, either by higher prices or shortages, because it is something that people absolutely have to have at any cost. There would be very few examples of a perfect inelastic demand. Some people need a certain kind of medicine to treat their disease, such as a severe diabetic who needs insulin; this is a perfectly inelastic demand. A heroin addict must have his or her heroin, regardless of cost, so that too is a perfectly inelastic demand. But most products have some elasticity of demand. If you cannot afford fruit juice, you can probably drink water instead.