CUET UG Booster Economics 5 Test (M2)
š Answers are locked once submitted ā results and explanations appear at the end.
QUESTION 1 OF 20
Match the Following terms from the concept of equilibrium:
| List I | List II |
|---|---|
| 1. Self-interested objective of consumers | a. Maximise their respective profits |
| 2. Self-interested objective of firms | b. Maximise their respective preference |
| 3. Equilibrium definition | c. Plans of all consumers and firms match |
| 4. Market disequilibrium | d. Excess demand or excess supply exists |
QUESTION 2 OF 20
Which of the following statements about equilibrium conditions are correct?
I. Both the consumers' and firms' objectives are compatible in equilibrium.
II. The market demand is greater than market supply in equilibrium.
III. Equilibrium is a zero excess demand-zero excess supply situation.
QUESTION 3 OF 20
In a perfectly competitive market with free entry and exit, how is the equilibrium price determined?
QUESTION 4 OF 20
Arrange the logical sequence showing how a market clears when demand shifts rightward:
1. Initial equilibrium is at p0, q0.
2. Market demand shifts rightward to DD2.
3. At p0, there is excess demand, causing consumers to pay a higher price.
4. Price rises until a new equilibrium is reached where market clears at a higher price and quantity.
QUESTION 5 OF 20
If the demand curve is qD = 200 ā p and the supply curve is qS = 120 + p, calculate the equilibrium quantity.
QUESTION 6 OF 20
At equilibrium, if the government imposes a specific tax 't' per unit, the balance condition shifts. However, in the standard free market, the balance condition for equilibrium quantity implies that excess demand equals ________ and excess supply equals ________.
QUESTION 7 OF 20
Assertion (A): Excess demand occurs at any price greater than the equilibrium price.
Reason (R): At a price greater than p*, the quantity demanded qD is greater than the quantity supplied qS.
QUESTION 8 OF 20
Arrange the events that cause and resolve excess demand:
1. Prevailing price is below equilibrium.
2. Consumers are unable to obtain the commodity.
3. Consumers are willing to pay more, pushing the price up.
4. Quantity demanded falls and quantity supplied increases until equilibrium.
QUESTION 9 OF 20
Match the following expressions algebraically:
| List I | List II |
|---|---|
| 1. Excess Demand (ED) | a. qS ā qD |
| 2. Excess Supply (ES) | b. qD ā qS |
| 3. Market equilibrium | c. qD = qS |
| 4. Shortage situation | d. qD>qS ā |
QUESTION 10 OF 20
When the government imposes a price floor above the equilibrium price, it directly causes an ________ in the market.
QUESTION 11 OF 20
Which of the following accurately describes the adjustment when the price rises due to excess demand?
QUESTION 12 OF 20
Which of the following statements is/are correct about a fall in market price?
I. A fall in price occurs when there is excess supply.
II. As price falls, quantity demanded rises.
III. As price falls, quantity supplied increases.
QUESTION 13 OF 20
Match the Following concepts related to Adam Smith's Invisible Hand:
| List I | List II |
|---|---|
| 1. Imbalance with excess demand | a. Invisible hand reaches equilibrium |
| 2. Imbalance with excess supply | b. Invisible hand lowers the price |
| 3. Reaching zero excess demand | c. Invisible hand raises the price |
| 4. Persistent shortage situation | d. Price continues to rise until equilibrium |
QUESTION 14 OF 20
Concept Equation:
If the Invisible Hand adjusts price based on the gap between demand and supply, then Īp\Delta pĪp (change in price) is directly proportional to:
QUESTION 15 OF 20
Whenever market supply is not equal to market demand, the market is not in equilibrium, resulting in a tendency for the ________ to change.
QUESTION 16 OF 20
Arrange the sequence of adjustment when the supply curve shifts leftward:
1. Excess demand is created at the prevailing price.
2. Market supply curve shifts leftward to SS2ā.
3. The new equilibrium is attained at a higher price.
4. Consumers willing to pay higher prices drive the market price up.
QUESTION 17 OF 20
Match the Following graphical shifts with their outcomes on the intersection point:
| List I | List II |
|---|---|
| 1. Demand shifts right, supply constant | a. Price decreases, quantity increases |
| 2. Supply shifts right, demand constant | b. Price decreases, quantity decreases |
| 3. Demand shifts left, supply constant | c. Price increases, quantity increases |
| 4. Supply shifts left, demand constant | d. Price increases, quantity decreases |
QUESTION 18 OF 20
In the equilibrium graph (Figure 5.1), what is located on the y-axis?
QUESTION 19 OF 20
QUESTION 20 OF 20
Test Complete!
Answer Review
1 Match the Following terms from the concept of equilibrium:
| List I | List II |
|---|---|
| 1. Self-interested objective of consumers | a. Maximise their respective profits |
| 2. Self-interested objective of firms | b. Maximise their respective preference |
| 3. Equilibrium definition | c. Plans of all consumers and firms match |
| 4. Market disequilibrium | d. Excess demand or excess supply exists |
Consumers aim to maximize satisfaction (preferences/utility). Firms aim to maximize profits. Equilibrium exists when market plans of buyers and sellers are compatible.
In a competitive market, consumers purchase goods to maximize their preferences (utility) while firms produce goods to maximize their profits. Market equilibrium occurs when the quantity demanded equals the quantity supplied, meaning the plans of consumers and firms are compatible. Disequilibrium exists whenever excess demand or excess supply is present. Thus, 1 ā b (Consumers maximize preferences.) 2 ā a (Firms maximize profits.) 3 ā c (Equilibrium means all market plans are compatible.) 4 ā d (Disequilibrium means excess demand or excess supply exists.) Therefore, Option A correctly matches every pair according to NCERT.
- Option B ā Incorrect because consumers do not maximize profits; firms do.
- Option C ā Incorrect because firms do not represent the equilibrium definition.
- Option D ā Incorrect because equilibrium is not the objective of consumers.
Used
- Option Grouping
Application:
- First identify the obvious pair:
- Firms ā Profit
- Consumers ā Preference
- The remaining two pairs automatically match equilibrium and disequilibrium.
Final Logic:
- Correct economic objectives immediately eliminate all options except Option A.
Consumers ā Preference | Firms ā Profit
2 Which of the following statements about equilibrium conditions are correct?
I. Both the consumers' and firms' objectives are compatible in equilibrium.
II. The market demand is greater than market supply in equilibrium.
III. Equilibrium is a zero excess demand-zero excess supply situation.
Equilibrium means demand equals supply. Excess demand is zero. Buyers' and sellers' plans are compatible.
In market equilibrium, the quantity demanded equals the quantity supplied. Therefore, there is neither excess demand nor excess supply. Statement I is correct because consumers maximize utility while firms maximize profits, and both objectives are simultaneously fulfilled in equilibrium. Statement II is incorrect because demand cannot exceed supply in equilibrium. If it did, excess demand would exist. Statement III is correct because equilibrium is precisely a zero excess demand and zero excess supply situation. Hence, Option C is correct.
- Option A ā Incorrect because Statement II is false.
- Option B ā Incorrect because Statement II is false.
- Option D ā Incorrect because all three statements are not correct.
Used
- Elimination
Application:
- Check Statement II first. Since equilibrium requires demand = supply, Statement II is false. Eliminate every option containing Statement II.
Final Logic:
- Only Option C excludes the incorrect statement.
Equilibrium = Demand = Supply = Zero Excess
3 In a perfectly competitive market with free entry and exit, how is the equilibrium price determined?
Equilibrium price is determined by market demand and market supply. It is established where the two curves intersect. At this point, quantity demanded equals quantity supplied.
According to NCERT, the equilibrium price is determined at the point where the market demand curve intersects the market supply curve. At this point: Quantity demanded equals quantity supplied. The market clears without shortage or surplus. The equilibrium price and equilibrium quantity are simultaneously determined. Therefore: Option B correctly states the NCERT concept. Option A is incorrect because consumers' maximum willingness to pay alone does not determine market equilibrium. Option C is incorrect because government price ceilings are market interventions and do not determine competitive equilibrium. Option D is incorrect because the equilibrium price is not always equal to the minimum average cost. Although this may occur under specific long-run perfectly competitive conditions, it is not the general rule for determining market equilibrium price. Therefore, Option B is correct.
- Option A) It is set at the maximum price consumers are willing to pay. ā Market equilibrium depends on both demand and supply, not consumers alone.
- Option C) It is fixed by government price ceiling policies. ā Price ceilings are government interventions that alter market outcomes rather than determine competitive equilibrium.
- Option D) It is always equal to the minimum average cost of the firms. ā This is not the general condition for determining equilibrium price, and the word "always" makes the statement incorrect.
Used
- Contextual/Tonal Matching
Application:
- Recall the NCERT definition of market equilibrium and identify the option that exactly matches it.
Final Logic:
- Equilibrium price is determined where the market demand curve intersects the market supply curve; therefore, Option B is correct.
Demand ā© Supply = Equilibrium Price
4 Arrange the logical sequence showing how a market clears when demand shifts rightward:
1. Initial equilibrium is at p0, q0.
2. Market demand shifts rightward to DD2.
3. At p0, there is excess demand, causing consumers to pay a higher price.
4. Price rises until a new equilibrium is reached where market clears at a higher price and quantity.
Begin at initial equilibrium. Demand increases. Excess demand raises price. New equilibrium is established.
Initially, the market is in equilibrium at (p0, q0). When market demand shifts rightward to DD2, the original equilibrium price p0 is no longer sufficient to clear the market. At p0, quantity demanded exceeds quantity supplied, creating excess demand. Buyers compete for the limited quantity available, causing the market price to rise. As the price increases, quantity demanded falls and quantity supplied rises until a new equilibrium is established at a higher price and a higher quantity. Therefore, the correct logical sequence is: 1 ā 2 ā 3 ā 4 Hence, Option B is correct.
Used
- Contextual/Tonal Matching
Application:
- Follow the chronological sequence of market adjustment after a rightward shift in demand.
Final Logic:
- Initial Equilibrium ā Demand Shift ā Excess Demand ā New Equilibrium, therefore Option A is correct.
Equilibrium ā Shift ā Shortage ā New Equilibrium
5 If the demand curve is qD = 200 ā p and the supply curve is qS = 120 + p, calculate the equilibrium quantity.
At equilibrium, demand equals supply. Solve for price first. Substitute the equilibrium price into either equation.
At equilibrium, qD = qS Therefore, 200 ā p = 120 + p 80 = 2p p = 40 Substitute p = 40 into either equation: q = 200 ā 40 = 160 or q = 120 + 40 = 160 Thus, the equilibrium quantity is 160. Hence, Option C is correct.
- Option A) 40 ā This is the equilibrium price, not the equilibrium quantity.
- Option B) 80 ā This results from an incorrect calculation.
- Option D) 200 ā This does not satisfy both the demand and supply equations simultaneously.
Used
- Substitution
Application:
- Set qD = qS, solve for the equilibrium price, and substitute it into either equation to obtain the equilibrium quantity.
Final Logic:
- qD = qS ā p = 40 ā q = 160, therefore Option C is correct.
Demand = Supply ā Solve p ā Find q
6 At equilibrium, if the government imposes a specific tax 't' per unit, the balance condition shifts. However, in the standard free market, the balance condition for equilibrium quantity implies that excess demand equals ________ and excess supply equals ________.
Market equilibrium occurs when demand equals supply. There is no shortage or surplus at equilibrium. Hence, both excess demand and excess supply are zero.
In a perfectly competitive market, equilibrium exists when the quantity demanded equals the quantity supplied. Mathematically, qD = qS Therefore, Excess Demand = qD ā qS = 0 and Excess Supply = qS ā qD = 0 When the government imposes a specific tax t per unit, the supply curve shifts and a new equilibrium is established. However, the question specifically refers to the standard free-market equilibrium, where both excess demand and excess supply are zero. Therefore: Option D is correct. Option A is incorrect because equilibrium cannot have positive excess demand or negative excess supply. Option B is incorrect because equilibrium is not represented by arbitrary numerical values. Option C is incorrect because price and cost do not describe equilibrium conditions.
Used
- Elimination
Application:
- Recall the basic equilibrium condition where neither shortage nor surplus exists.
Final Logic:
- Excess Demand = 0 and Excess Supply = 0; therefore, Option D is correct.
7 Assertion (A): Excess demand occurs at any price greater than the equilibrium price.
Reason (R): At a price greater than p*, the quantity demanded qD is greater than the quantity supplied qS.
Excess demand occurs below equilibrium price. Excess supply occurs above equilibrium price. Therefore, both Assertion and Reason are incorrect.
According to NCERT, *excess demand exists when the prevailing market price is below the equilibrium price (p)**. When price is below equilibrium: qD > qS When price is above equilibrium: qS > qD Hence: The Assertion is false because excess demand does not occur above the equilibrium price. The Reason is also false because at a price greater than p*, quantity demanded (qD) is less than quantity supplied (qS). Therefore, Option A is correct.
Used
- Conceptual Elimination
Application:
- Recall the relationship between market price and excess demand/excess supply.
Final Logic:
- Below p* ā qD > qS (Excess Demand)
- Above p* ā qS > qD (Excess Supply)
- Hence, both statements are false.
High Price ā Surplus
8 Arrange the events that cause and resolve excess demand:
1. Prevailing price is below equilibrium.
2. Consumers are unable to obtain the commodity.
3. Consumers are willing to pay more, pushing the price up.
4. Quantity demanded falls and quantity supplied increases until equilibrium.
Price is below equilibrium. Shortage develops. Buyers compete by offering higher prices. Market returns to equilibrium.
The adjustment process follows a logical sequence: 1. The prevailing price is below equilibrium. 2. Quantity demanded exceeds quantity supplied, creating a shortage. 3. Consumers compete by offering higher prices. 4. As price rises, quantity demanded falls and quantity supplied increases until equilibrium is restored. Thus, the correct order is: 1 ā 2 ā 3 ā 4 Hence, Option B is correct.
Used
- Contextual/Tonal Matching
Application:
- Arrange the events according to the natural market adjustment process.
Final Logic:
- Low Price ā Shortage ā Higher Price ā Equilibrium, therefore Option B is correct.
9 Match the following expressions algebraically:
| List I | List II |
|---|---|
| 1. Excess Demand (ED) | a. qS ā qD |
| 2. Excess Supply (ES) | b. qD ā qS |
| 3. Market equilibrium | c. qD = qS |
| 4. Shortage situation | d. qD>qS ā |
Excess demand means demand exceeds supply. Excess supply means supply exceeds demand. Equilibrium occurs when demand equals supply.
Definitions: Excess Demand (ED): ED = qD ā qS Excess Supply (ES): ES = qS ā qD Market Equilibrium: qD = qS Shortage Situation: qD > qS Therefore: 1 ā b 2 ā a 3 ā c 4 ā d Hence, Option B is correct.
Used
- Option Grouping
Application:
- Match each concept with its corresponding algebraic expression.
Final Logic:
- Only Option B correctly matches all four expressions.
10 When the government imposes a price floor above the equilibrium price, it directly causes an ________ in the market.
A price floor is a minimum legal price. When set above equilibrium, producers supply more than consumers demand. This creates a surplus (excess supply).
A price floor is a government-imposed minimum legal price. When it is fixed above the equilibrium price, producers are willing to supply more, while consumers demand less. Therefore, qS > qD This creates excess supply (surplus) in the market. Hence: Option C is correct. Option A is incorrect because the invisible hand refers to the market mechanism, not the direct effect of a price floor. Option B is incorrect because excess demand occurs when price is below equilibrium. Option D is incorrect because the immediate effect of a binding price floor is excess supply, not simply an equilibrium shift.
Used
- Conceptual Elimination
Application:
- Recall the effect of a binding price floor on demand and supply.
Final Logic:
- Price Floor Above Equilibrium ā qS > qD ā Excess Supply, therefore Option C is correct.
11 Which of the following accurately describes the adjustment when the price rises due to excess demand?
Excess demand occurs when quantity demanded exceeds quantity supplied. Buyers compete for limited goods, pushing the price upward. A higher price reduces demand and encourages greater supply until equilibrium is restored.
When there is excess demand (qD > qS), the prevailing market price is below the equilibrium price. Consumers compete for the limited quantity available, causing the market price to rise. As the price increases: Quantity demanded decreases (movement upward along the demand curve). Quantity supplied increases (movement upward along the supply curve). The adjustment continues until: qD = qS At this point, the market reaches equilibrium. Therefore, Option D correctly explains the market adjustment process according to NCERT.
- Option A ā Incorrect because firms do not lower the price when excess demand exists. Market forces push the price upward.
- Option B ā Incorrect because although consumers buy less as the price rises, firms generally supply more, not less.
- Option C ā Incorrect because excess demand is corrected through a movement along the demand and supply curves, not by a shift in the demand curve itself.
Used
- Elimination
Application:
- Eliminate options that involve price reduction, incorrect supply response, or curve shifts instead of movements along the curves.
Final Logic:
- Only Option D correctly describes the adjustment mechanism under excess demand.
Shortage ā Price ā ā Demand ā ā Supply ā ā Equilibrium
12 Which of the following statements is/are correct about a fall in market price?
I. A fall in price occurs when there is excess supply.
II. As price falls, quantity demanded rises.
III. As price falls, quantity supplied increases.
Excess supply causes the market price to fall. A lower price increases quantity demanded. A lower price decreases quantity supplied.
When excess supply exists (qS > qD), sellers compete to sell their products by lowering prices. As the market price falls: Quantity demanded increases because consumers are willing to purchase more at a lower price. Quantity supplied decreases because producers are willing to supply less at lower prices. Therefore: Statement I is correct. Statement II is correct. Statement III is incorrect because supply decreases rather than increases when price falls. Hence, Option A is the correct answer.
- Option B ā Incorrect because Statement III is false.
- Option C ā Incorrect because Statement III is false.
- Option D ā Incorrect because all three statements are not correct.
Used
- Elimination
Application:
- Recall the law of supply: a fall in price reduces quantity supplied, immediately eliminating all options containing Statement III.
Final Logic:
- Only Option A contains the correct combination of statements.
Price ā ā Demand ā ā Supply ā
13 Match the Following concepts related to Adam Smith's Invisible Hand:
| List I | List II |
|---|---|
| 1. Imbalance with excess demand | a. Invisible hand reaches equilibrium |
| 2. Imbalance with excess supply | b. Invisible hand lowers the price |
| 3. Reaching zero excess demand | c. Invisible hand raises the price |
| 4. Persistent shortage situation | d. Price continues to rise until equilibrium |
Excess demand pushes prices upward. Excess supply pushes prices downward. The invisible hand guides the market toward equilibrium.
According to Adam Smith's concept of the Invisible Hand, self-interested actions of buyers and sellers automatically move the market toward equilibrium. Thus, Excess demand leads to a rise in price. Excess supply leads to a fall in price. Zero excess demand indicates that equilibrium has been reached. A persistent shortage continues to increase the market price until equilibrium is restored. Hence, the correct matching is: 1 ā c 2 ā b 3 ā a 4 ā d Therefore, Option A is correct.
- Option B ā Incorrect because excess demand does not lower the price.
- Option C ā Incorrect because equilibrium is not the immediate outcome of excess demand.
- Option D ā Incorrect because zero excess demand signifies equilibrium, not a fall in price.
Used
- Option Grouping
Application:
- First identify the obvious relationships:
- Excess demand ā Price rises.
- Excess supply ā Price falls.
- The remaining matches follow automatically.
Final Logic:
- Only Option A correctly matches all four concepts.
Supply ā ā Price ā
14 Concept Equation:
If the Invisible Hand adjusts price based on the gap between demand and supply, then Īp\Delta pĪp (change in price) is directly proportional to:
Price changes according to the imbalance between demand and supply. Excess demand raises price. Excess supply lowers price.
The Invisible Hand adjusts prices according to the difference between quantity demanded and quantity supplied. When: qD > qS there is excess demand and prices rise. When: qS > qD there is excess supply and prices fall. Therefore, Īp ā (qD ā qS) Hence, Option C is correct.
- Option A ā The ratio of supply to demand does not directly determine the price adjustment.
- Option B ā The total of demand and supply does not measure market imbalance.
- Option D ā The product of demand and supply has no role in the NCERT explanation of market equilibrium.
Used
- Dimensional/Conceptual Analysis
Application:
- The market adjusts according to the difference, not the sum, ratio, or product of demand and supply.
Final Logic:
- Only Option C represents the market imbalance responsible for price adjustment.
ED = qD ā qS
15 Whenever market supply is not equal to market demand, the market is not in equilibrium, resulting in a tendency for the ________ to change.
Disequilibrium exists when demand differs from supply. Market forces automatically adjust the price. Price changes restore equilibrium.
Whenever qD ā qS the market is in disequilibrium. This creates either excess demand or excess supply. The market adjusts through changes in price until qD = qS Therefore, the variable that changes naturally is price, making Option B correct.
- Option A ā Incorrect because the government does not automatically intervene whenever disequilibrium occurs.
- Option C ā Incorrect because product quality is unrelated to the market adjustment process.
- Option D ā Incorrect because total cost is not the variable that adjusts to eliminate market disequilibrium.
Used
- Contextual/Tonal Matching
Application:
- Identify the variable that responds automatically to market shortages or surpluses.
Final Logic:
- Only price changes automatically through market forces to restore equilibrium.
No Balance ā Price Changes
16 Arrange the sequence of adjustment when the supply curve shifts leftward:
1. Excess demand is created at the prevailing price.
2. Market supply curve shifts leftward to SS2ā.
3. The new equilibrium is attained at a higher price.
4. Consumers willing to pay higher prices drive the market price up.
Supply decreases first. Excess demand arises at the existing price. Buyers bid up the price. A new equilibrium is established at a higher price.
The correct adjustment sequence is: 1. Market supply shifts leftward to SS2. 2. At the prevailing price, qD > qS, creating excess demand. 3. Consumers compete by offering higher prices. 4. As price rises, quantity demanded falls and quantity supplied increases until a new equilibrium is reached. Therefore, the correct order is: 2 ā 1 ā 4 ā 3 Hence, Option D is correct.
- Option A ā Incorrect because excess demand cannot occur before the supply curve shifts.
- Option B ā Incorrect because consumers cannot bid up prices before excess demand arises.
- Option C ā Incorrect because price cannot rise before the supply shift occurs.
Used
- Contextual/Tonal Matching
Application:
- Arrange the events according to the natural market adjustment process after a decrease in supply.
Final Logic:
- Supply decreases ā Excess demand ā Price rises ā New equilibrium.
Supply ā ā Shortage ā Price ā ā Balance
17 Match the Following graphical shifts with their outcomes on the intersection point:
| List I | List II |
|---|---|
| 1. Demand shifts right, supply constant | a. Price decreases, quantity increases |
| 2. Supply shifts right, demand constant | b. Price decreases, quantity decreases |
| 3. Demand shifts left, supply constant | c. Price increases, quantity increases |
| 4. Supply shifts left, demand constant | d. Price increases, quantity decreases |
Rightward demand shift raises both price and quantity. Rightward supply shift lowers price and increases quantity. Leftward demand shift lowers both price and quantity. Leftward supply shift raises price and lowers quantity.
The equilibrium outcomes are: Demand shifts right ā Price ā, Quantity ā Supply shifts right ā Price ā, Quantity ā Demand shifts left ā Price ā, Quantity ā Supply shifts left ā Price ā, Quantity ā Therefore, the correct matching is: 1 ā c 2 ā a 3 ā b 4 ā d Hence, Option D is correct.
- Option A ā Incorrect because a rightward demand shift does not reduce price.
- Option B ā Incorrect because a rightward supply shift decreases price rather than increases it.
- Option C ā Incorrect because a leftward demand shift cannot increase quantity.
Used
- Option Grouping
Application:
- Recall the four standard demand-supply graph outcomes and match each shift with its corresponding price and quantity change.
Final Logic:
- Only Option C correctly matches all four graphical outcomes.
Supply ā Price Opposite, Quantity Same
18 In the equilibrium graph (Figure 5.1), what is located on the y-axis?
The demand-supply graph uses price and quantity axes. Price is measured vertically. Quantity is measured horizontally.
According to the standard NCERT demand-supply diagram: Y-axis (Vertical Axis): Price X-axis (Horizontal Axis): Quantity The equilibrium point is determined by the intersection of the demand and supply curves. Thus, the vertical axis always measures price, making Option D correct.
- Option A ā Incorrect because quantity is plotted on the horizontal (x) axis.
- Option B ā Incorrect because excess demand is represented by the gap between demand and supply, not as an axis.
- Option C ā Incorrect because firms' profit is not represented on the equilibrium graph.
Used
- Odd One Out
Application:
- Recognize the standard axes used in demand-supply graphs and eliminate unrelated concepts.
Final Logic:
- The vertical axis in an equilibrium graph always represents price.
X = Quantity
19
Equilibrium occurs where demand equals supply. Equate the two equations first. Solve for equilibrium price afterward.
The passage gives: qD = 200 ā p qS = 120 + p At equilibrium, qD = qS Substituting the equations, 200 ā p = 120 + p* This is the first algebraic step in finding the equilibrium price. Therefore, Option A is correct.
- Option B ā Incorrect because the demand and supply equations are written incorrectly.
- Option C ā Incorrect because the equilibrium price cannot be obtained without first equating demand and supply.
- Option D ā Incorrect because this equation appears only after simplifying the correct first equation.
Used
- Substitution
Application:
- Substitute the demand and supply equations into the equilibrium condition qD = qS.
Final Logic:
- The first algebraic step is:
- 200 ā p = 120 + p*
Equilibrium ā Demand = Supply
20
Equate demand and supply. Solve for equilibrium price. The equilibrium price is ā¹40.
At equilibrium, qD = qS Substitute the given equations: 200 ā p = 120 + p Rearranging, 80 = 2p p = 40 Therefore, p = 40* Hence, Option B is correct.
- Option A ā Substituting p = 20 does not satisfy qD = qS.
- Option C ā Substituting p = 80 does not satisfy qD = qS.
- Option D ā 160 is the equilibrium quantity (q*), not the equilibrium price (p*).
Used
- Substitution
Application:
- Set qD = qS and solve for p.
Final Logic:
- 200 ā p = 120 + p ā p = 40 ā p = 40*
Demand = Supply ā Solve p First*
