This question examines cross-price elasticity of demand (XED) between popcorn and movie tickets. XED measures how quantity demanded of one good responds to price changes of another, with negative values indicating complements and positive values indicating substitutes. Movie ticket prices rise 20% while popcorn quantity falls 10%, yielding XED = -10%/+20% = -0.5. The negative XED confirms these are complementary goods—people buy popcorn when attending movies, so higher movie prices reduce both movie attendance and popcorn purchases. Students often confuse this with own-price elasticity (where popcorn's own price affects popcorn demand). For XED problems: identify which good's price changed and which good's quantity changed, calculate the sign, then interpret (negative = complements, positive = substitutes).

This question involves cross-price elasticity of demand (XED). XED measures how the quantity demanded of one good changes in response to a price change in another good, with positive XED indicating substitutes, negative indicating complements, and zero indicating unrelated. Here, the price of tea increases by 10%, and the quantity demanded of coffee increases by 10%, resulting in XED = 10%/10% = 1. Since XED is positive, coffee and tea are substitutes, as demand for one rises when the other's price increases. A common misconception is mixing XED signs with YED, but XED focuses on cross-good price effects. To analyze similar problems, first determine the sign of the elasticity coefficient. Then, match it to the categories: positive for substitutes, negative for complements.

This question involves income elasticity of demand (YED). YED measures how the quantity demanded of a good changes in response to a change in income, with a positive YED indicating a normal good and a negative YED indicating an inferior good. Here, income increases by 10%, and the quantity demanded of soup decreases by 10%, resulting in YED = -10%/10% = -1. Since YED is negative, soup is an inferior good, as demand falls with rising income. A common misconception is assuming negative YED means normal, but the sign directly indicates inferiority. To analyze similar problems, first determine the sign of the elasticity coefficient. Then, match it to the categories: negative for inferior goods, positive for normal.

This question tests income elasticity of demand (YED) for bus rides. YED measures how quantity demanded responds to income changes, where positive YED indicates a normal good and negative YED indicates an inferior good. The data shows that when income falls by 10%, bus ride demand falls from 1,000 to 950 rides (a 5% decrease), yielding YED = -5%/-10% = +0.5. The positive sign confirms that bus rides are a normal good in this situation—consumers reduce their bus usage when income falls, suggesting they view bus transportation as something they want to maintain when they can afford it. A common misconception is assuming all public transportation must be inferior goods, but the classification depends on the specific market and consumer base. To determine good types, calculate YED's sign: when income and quantity move in the same direction (both up or both down), YED is positive, indicating a normal good. This finding might reflect a market where bus riders have limited alternative transportation options.

This question examines income elasticity of demand (YED) for used clothing. YED measures how quantity demanded responds to income changes, where positive values indicate normal goods and negative values indicate inferior goods. Income rises from $3,000 to $3,300 (10% increase) and used clothing rises from 10 to 11 items (10% increase), giving YED = +10%/+10% = +1.0. The positive YED indicates used clothing is a normal good for this consumer—contrary to common assumptions that used goods are inferior. A frequent error is assuming all second-hand goods must be inferior goods, but elasticity measures actual behavior, not stereotypes. To solve YED problems: calculate percentage changes, determine the sign (positive = normal), and avoid preconceptions about good types.

This question tests cross-price elasticity of demand (XED) between tea and coffee. XED measures how quantity demanded of one good (tea) responds to price changes of another good (coffee), where positive XED indicates substitutes and negative XED indicates complements. Coffee price rises 10% and tea quantity rises 5%, giving XED = +5%/+10% = +0.5. The positive XED confirms tea and coffee are substitutes—when coffee becomes more expensive, consumers switch to tea. A common mistake is thinking positive XED means complements (it's actually the opposite). To solve XED problems: calculate the sign first (positive = substitutes, negative = complements), then verify the logic makes economic sense.

This question examines cross-price elasticity of demand (XED) between jelly and peanut butter. XED measures how quantity demanded of one good responds to price changes of another good, where positive indicates substitutes, negative indicates complements, and zero indicates unrelated goods. Peanut butter price rises 10% but jelly quantity remains unchanged (0%), giving XED = 0%/10% = 0. The zero XED indicates these goods are unrelated in this consumer's preferences—surprising given they're often complements. Students might assume all paired foods must be complements, but elasticity measures actual consumer behavior, not assumptions. For XED problems: calculate the actual elasticity value first, then interpret based on the sign (positive = substitutes, negative = complements, zero = unrelated).

This question involves income elasticity of demand (YED). YED measures how the quantity demanded of a good changes in response to a change in income, with a positive YED indicating a normal good and a negative YED indicating an inferior good. Here, income decreases by 10%, and the quantity demanded of bus passes increases by 10%, resulting in YED = 10%/-10% = -1. Since YED is negative, bus passes are an inferior good, as demand rises when income falls. A common misconception is assuming a demand increase with falling income means normal, but the negative sign confirms inferiority. To analyze similar problems, first determine the sign of the elasticity coefficient. Then, match it to the categories: negative for inferior, positive for normal.

This question tests income elasticity of demand (YED) for movie theater tickets. YED measures how quantity demanded responds to income changes, where positive YED indicates a normal good (consumed more as income rises) and negative YED indicates an inferior good. The data shows that when income rises by 25%, ticket demand increases from 400 to 420 tickets (a 5% increase), yielding YED = +5%/+25% = +0.2. The positive sign confirms that movie tickets are a normal good—consumers purchase more entertainment as their income increases. A common misconception is confusing the sign interpretation: some students think negative YED means "bad" and positive means "good," but it's about consumption patterns, not quality. To interpret YED correctly, focus on the sign first: positive means normal (income and quantity move together), negative means inferior (income and quantity move oppositely). The relatively low elasticity (0.2) suggests movie tickets are a necessity within entertainment spending.

This question asks about cross-price elasticity of demand (XED) for coffee with respect to tea's price. XED measures how the quantity demanded of one good responds to price changes in another good, where positive XED indicates substitutes and negative XED indicates complements. Here, tea's price rises by 10% and coffee's quantity demanded rises by 5%, giving XED = (+5%)/(+10%) = +0.5. The positive sign means coffee and tea are substitutes—when tea becomes more expensive, consumers switch to coffee. A common error is confusing the sign: some think goods consumed together must have positive XED, but complements actually have negative XED (when one's price rises, demand for both falls). To avoid mistakes, always check the sign first: if price and quantity move in the same direction (both up or both down), XED is positive (substitutes); if they move oppositely, XED is negative (complements).