Elasticity: End of Chapter Problem Let's work out an example to get a sense of what elasticity of demand means in practice. @ Macmillan Learning a. If the elasticity of demand for college textbooks is -0.1, and the price of textbooks increases by 20%, how much will the quantity demanded change, and in what direction? In which direction? Quantity demanded changes by O down O up b. In your answer to part a, was your answer in percentages or in total number of textbooks? The answer is a percentage. O the number of textbooks