4. Based on the following table which indicates expenditure of the household on a Commodity, answer the questions that follow (The price of the good is Br10) (6 Points). Quantity Demanded Income 10,000 20,000 30 000 40,000 50,000 50 60 70 80 90 a) Calculate income elasticity of demand, if income increases from Br.10, 000 to Br.20, 000 and if income increases from Br.40, 000 to Br. 50,000. b) Is this a normal or an inferior or a luxury good? Justify. c) Does the proportion of household income spent on this good increase or decrease as income increases? Why?​