9. Which of the following is a common characteristic of goods for which the demand is inelastic? a. Consumers most often spend a small proportion of their budget on the item. b. There are several substitutes available. c. The period of time for which demand exists for the product is long. d. It is often not a necessity for most people. 10. Which of the following is a common characteristic of goods for which the demand is elastic? a. There are usually no substitutes available. b. It is often a necessity for most people. c. The period of time for which demand exists for the product is long. d. Consumers most often spend a small proportion of their budget on the item. 11. The following items have the same approximate degree of demand elasticity, except for one. Which one is the odd one out? a. gasoline b. milk c. cellphones d. pharmaceutical drugs 12. An airline finds that when it raises its fares on certain flights, total revenue increases, although the total number of passengers falls. What conclusion can be drawn? a. Demand is inelastic because the number of passengers has decreased. b. Demand is inelastic because sales revenues have increased. c. Demand is elastic because sales revenue has decreased. d. Demand is elastic because the number of passengers has decreased