Question 1

Given the demand equation $$P = 800 - 2Q_d$$ and the supply equation $$P = 200 + Q_s$$, what is the equilibrium price and quantity in the market?

Accepted Answer

$$P = 400, Q = 200$$

Question 2

If the demand equation is $$P = 400 - 0.3Q_d$$ and the supply equation is $$P = 40 + 0.3Q_s$$, what is the equilibrium quantity?

Accepted Answer

$$Q = 600$$

Question 3

Suppose the demand equation is $$Q_d = 20 - 2P$$ and the supply equation is $$Q_s = -10 + 2P. $$What is the equilibrium price?

Accepted Answer

$$P = 7.5$$

Question 4

Given the supply equation $$Q_s = -40 + 30P$$, what is the quantity supplied when $$P = 5$$?

Accepted Answer

$$Q_s = 110$$

Question 5

If the demand equation is $$Q_d = 100 - 10P$$, what is the price when the quantity demanded is $$0$$?

Accepted Answer

$$P = 10$$

Question 6

A market has the following data: at $$P = 1.25$$, $$Q_d = 700$$ and $$Q_s = 700. $$What does this indicate?

Accepted Answer

The market is in equilibrium.

Question 7

If the supply equation is $$P = 2Q - 20$$, what is the price when $$Q = 15$$?

Accepted Answer

$$P = 10$$

Question 8

Given the demand equation $$Q_d = 150 - 2P$$ and the supply equation $$Q_s = -30 + 4P$$, what is the equilibrium quantity?

Accepted Answer

$$Q = 90$$

Question 9

If the price is set above the equilibrium price, what will occur in the market?

Accepted Answer

A surplus will occur.

Question 10

Which of the following best describes the vertical intercept in the demand equation $$P = a - bQ_d$$?

Accepted Answer

$$a$$, the price when quantity demanded is zero.

Question 11

If the supply equation is $$P = 200 + Q_s$$ and the equilibrium price is $$400$$, what is the equilibrium quantity supplied?

Accepted Answer

$$Q_s = 200$$

Question 12

Given the demand equation $$Q_d = 70 - 0.5P$$ and the supply equation $$Q_s = -10 + 2P$$, what is the equilibrium price?

Accepted Answer

$$P = 32$$

Question 13

If the demand equation is $$Q_d = 80 - 4P$$ and the supply equation is $$Q_s = -20 + 2P$$, what is the equilibrium quantity?

Accepted Answer

$$Q = 40$$

Question 14

Which of the following is the correct formula for the inverse of the slope in the supply equation $$P = c + dQ_s$$?

Accepted Answer

$$1/d$$

Question 15

If the demand equation is $$Q_d = 100 - 5P$$ and the supply equation is $$Q_s = 20 + 3P$$, what is the equilibrium price?

Accepted Answer

$$P = 10$$

Question 16

A table shows that at $$P = 12$$, $$Q_s = 4000$$ and $$Q_d = 2000. $$What does this indicate?

Accepted Answer

There is a surplus of 2000 units.

Question 17

If the demand equation is $$Q_d = ab - 1bP$$, what does $$ab$$ represent?

Accepted Answer

The horizontal intercept.

Question 18

Given the supply equation $$Q_s = -10 + 2P$$, what is the price when $$Q_s = 10$$?

Accepted Answer

$$P = 10$$

Question 19

If the demand equation is $$P = 100 - Q_d$$ and the supply equation is $$P = 20 + Q_s$$, what is the equilibrium price?

Accepted Answer

$$P = 60$$

Question 20

Which of the following best describes market equilibrium?

Accepted Answer

Quantity demanded equals quantity supplied at a specific price.

Solving Demand and Supply Equations: Market Equilibrium in Microeconomics

Study Guide - Practice Questions