AP Micro Budget Line Slope & Shifts Quiz: Test Your Skills

📚 Quick Study Guide

• 💰 Budget Line Definition: Represents all possible combinations of two goods a consumer can purchase given their income and the prices of the goods.
• 📈 Slope of the Budget Line: The rate at which a consumer can trade one good for another. It is calculated as the negative ratio of the prices of the two goods. Mathematically, if the goods are X and Y, the slope is given by: $Slope = -\frac{P_X}{P_Y}$
• ✏️ Interpretation of the Slope: A slope of -2 means that for every unit of good X you consume, you must give up 2 units of good Y.
• ⬆️ Shift of the Budget Line: Occurs due to changes in income. An increase in income shifts the budget line outward (to the right), allowing the consumer to purchase more of both goods. A decrease in income shifts the budget line inward (to the left).
• 🔄 Rotation of the Budget Line: Occurs due to changes in the price of one of the goods. If the price of good X decreases, the budget line rotates outward along the X-axis, allowing the consumer to purchase more of good X. If the price of good X increases, the budget line rotates inward along the X-axis.
• 💡 Key Assumption: The budget line assumes that the consumer spends all their income on the two goods being considered.
• 🧮 Formula for Budget Line: $P_X * X + P_Y * Y = Income$, where $P_X$ is the price of good X, X is the quantity of good X, $P_Y$ is the price of good Y, and Y is the quantity of good Y.

Practice Quiz

1. What does the slope of the budget line represent?
   1. A) The consumer's preferences.
   2. B) The rate at which a consumer can trade one good for another.
   3. C) The consumer's income.
   4. D) The quantity of goods available.
2. If the price of good X is $5 and the price of good Y is $10, what is the slope of the budget line?
   1. A) -2
   2. B) 2
   3. C) -0.5
   4. D) 0.5
3. What causes a shift in the budget line?
   1. A) A change in consumer preferences.
   2. B) A change in income.
   3. C) A change in the price of both goods proportionally.
   4. D) Technological advancements.
4. If a consumer's income increases, what happens to the budget line?
   1. A) It shifts inward (to the left).
   2. B) It shifts outward (to the right).
   3. C) It rotates along the X-axis.
   4. D) It remains unchanged.
5. What causes a rotation of the budget line?
   1. A) A change in income.
   2. B) A change in the price of one of the goods.
   3. C) A proportional change in the prices of both goods.
   4. D) A change in consumer tastes.
6. Suppose a consumer has an income of $100. Good X costs $10 per unit, and Good Y costs $5 per unit. If the consumer spends all income on Good X, how many units of Good X can they buy?
   1. A) 5
   2. B) 10
   3. C) 20
   4. D) 100
7. If the price of good Y decreases, what happens to the budget line?
   1. A) It shifts inward.
   2. B) It shifts outward.
   3. C) It rotates outward along the Y-axis.
   4. D) It rotates inward along the Y-axis.