Target Exam

CUET

Subject

Economics

Chapter

Micro Economics: Market Equilibrium

Question:

What would be the equilibrium number of firms in a market of identical firms, when market demand function ($Q_d$), supply function of a single firm ($Q_{s1}$) and equilibrium price (P) are given as

$Q_d=180-2P$
$Q_{s1} = 15+ P$
$P = 15$

Options:

5

6

8

9

Correct Answer:

5

Explanation:

The correct answer is Option (1) → 5

We are given:

  • Market demand function: Qd = 180 − 2P

  • Supply function of a single firm: Qs₁ = 15 + P

  • Equilibrium price: P = 15

Step 1: Calculate market quantity demanded at P = 15 
$Q_d$ 180 − 2(15
          = 180 − 30
          = 150
Step 2: Calculate quantity supplied by one firm at P = 15
Qs₁ = 15+15 30
 
Step 3: Find number of identical firms (n) required to supply 150 units
n×Qs₁= $Q_d$
           ⇒ n×30=150
            ⇒ n = 150/30 =5