In the demand equation QD = 20 - 2 P, the rate at which quantity demanded changes when price changes equals:
1. 2 units decrease in quantity demanded for each dollar increase in price.
2. 20 units increase in quantity demanded for each dollar increase in price.
3. 20 units increase or decrease in quantity demanded for every dollar change in price.
4. 2 units increase in quantity demanded for every 20-dollar decrease in price.
5. 20 units increase in quantity demanded for every 2-dollar decrease in price
Question 12