I dont know what I am missing, help please

Overall Score: 12.50% Intro L1 L2 L3 L4 Question 1.3: Use the information regarding the price change to calculate the price elasticity of demand for Potato Chips. Round your answer to two decimal places (e.g., -3.02%). ( Price Elasticity of Demand for Potato Chips: 89.07 - 120 )/2 ( ( ( 2.75 + 3.4 1/2 Check Answer Calculating Price Elasticity of Demand Item: Potato Chips Price $2.75 Quantity 120 Old A bag of salted potato chips. New $3.40 89.07 Price Elasticity of Demand = ? Percentage Change 21.14% -29.59%