From the above, calculate the price elasticity of demand
price elasticity of demand is calculated as the;
percentage change in quantity demanded percentage change in price
Change in quantity = 500 - 400 = 100 % change = 100/100 = 1%
Change in price = 70 - 50 = 20 % change = 20/100 = 0.2%
price elasticity = 10.2 = 5