Price elasticity of demand when the price per unit of a product falls from taka 5 to taka 3, and the quantity purchased rises from 5 to 8 units as a result.

 It is shown that when the price of the product was tk.5, than the quantity of purchased product demand was 5 unit, but when its price falls from taka 5 to taka 3, than the quantity of purchased product demand increases from 5 unit to 8 unit. So the elasticity of demand is

 Q2‐Q1/Q2+Q1÷2

                    P2‐p1/P2+P1÷2