1. Price of commodity increases from ₹50 to ₹60 per unit. Quantity demand initially was 2000 units what should be the new quantity so that elasticity of demand is established to be unitary? Solution:   The following information is given:   Q = 200 units   Q 1 =? *ΔQ =Q 1 -Q     P = ₹ 50   P 1 = ₹60 ΔP = P 1 -P =60-50 = 10   E d =1   Interpretation : In order to get unitary elasticity of demand, new quantity should be 160 units. Note: We have used a negative sign in the quantity demanded (40) because it is decreased by 40 units. 2. Consider the demand for a good. At price ₹4, the demand for the good is 25 units. Suppose the price of the good increases to ₹5, and as a result, the demand for the good falls to 20 units. Calculate the price elasticity. Solution:   The following information is given:   Q = 25 units   Q 1 =20 units ΔQ =Q 1