A store raises the price of breakfast cereal from $2.20 to $2.80 In response, sales of milk drop from 310 gallons a day to 290. 5. What is the percentage change in price of cereal? 6. What is the percentage change in purchases of milk? 7. What is the cross-price elasticity of milk in response to a change in the price of cereal? 8. What does the number you found for #7 above mean