Which of the following events might shift the demand curve for apples to the left?
A. Apples become more expensive.
B. Pears, a substitute good for apples, go on sale.
C. Pie crusts, a complement to apples, go on sale.
D. A popular health blog suggests that eating apples will make you healthier.
The correct answer and explanation is:
The correct answer is B. Pears, a substitute good for apples, go on sale.
Explanation:
A demand curve shows the relationship between the price of a good and the quantity demanded by consumers. When something causes the entire demand curve to shift, it means the quantity demanded changes at every price level. A shift to the left means a decrease in demand.
Option A states that apples become more expensive. This causes a movement along the demand curve, not a shift. A higher price leads to lower quantity demanded, but the demand curve itself stays the same.
Option B states that pears, which are substitutes for apples, go on sale. Substitute goods are products that can replace each other, like apples and pears. If pears become cheaper, consumers may buy more pears instead of apples. This decreases the demand for apples at every price, shifting the demand curve for apples to the left.
Option C mentions pie crusts, which are complements to apples. Complement goods are used together, so if pie crusts become cheaper, people might buy more pie crusts and also more apples to use together. This would increase the demand for apples, shifting the demand curve to the right, not left.
Option D refers to a health blog suggesting apples make you healthier. Positive information like this tends to increase demand, as more consumers want to buy apples, shifting the demand curve to the right.
In summary, only when the price of a substitute good falls, like pears going on sale, will the demand for apples decrease and cause the demand curve for apples to shift left.