Use the following information to answer questions 1 and 2:
Suppose that a store decreases the price of laundry detergent from $4.10 to $3.50. As a result, quantity demanded increases from 210 to 230.
1. Using the mid-point approach, calculate the percentage change in price.
2. Using the mid-point elasticity approach, calculate price elasticity of demand. Your answer should be expressed in absolute value terms.