Question 2 a) Last year, Joan bought 50 pounds of hamburgers when her household income was RM40,000. This year, her household income was only RM30,000 and Joan bought 60 pounds of hamburgers. Holding everything else constant, Calculate Joan's income elasticity of demand for hamburgers. (4 Marks) b) If Joan wants to increase her total revenue, should it raise the price of hamburger? Why or why not