Class 12 Micro Economics - Chapter Theory of Consumer Behaviour NCERT Solutions | Explain why the budget line is downward

A consumer wants to consume two goods. The prices of the two goods are Rs 4
and Rs 5 respectively. The consumer’s income is Rs 20.
(i) Write down the equation of the budget line.
(ii) How much of good 1 can the consumer consume if she spends her entire
income on that good?
(iii) How much of good 2 can she consume if she spends her entire income on
that good?
(iv) What is the slope of the budget line?
Questions 5, 6 and 7 are related to question 4.

Suppose your friend is indifferent to the bundles (5, 6) and (6, 6). Are the preferences of your friend monotonic?

Suppose there are 20 consumers for a good and they have identical demand functions: 

d(p)=10–3pd(p)=10–3p for any price less than or equal to 103103 and d1(p)=0d1(p)=0 at any price greater than 103.

What is budget line?

What do you mean by an ‘inferior good’? Give some examples

Consider the demand curve D (p) = 10 – 3p. What is the elasticity at price 53?

Suppose a consumer wants to consume two goods which are available only in
integer units. The two goods are equally priced at Rs 10 and the consumer’s
income is Rs 40.
(i) Write down all the bundles that are available to the consumer.
(ii) Among the bundles that are available to the consumer, identify those which cost her exactly Rs 40.

Suppose a consumer’s preferences are monotonic. What can you say about her preference ranking over the bundles (10, 10), (10, 9) and (9, 9)?

What do you mean by substitutes? Give examples of two goods which are substitutes of each other.

Suppose the price elasticity of demand for a good is – 0.2. If there is a 5 % increase in the price of the good, by what percentage will the demand for the good go down?

Explain the concept of a production function

What would be the shape of the demand curve so that the total revenue curve is?

(a) A positively sloped straight line passing through the origin?

(b) A horizontal line?

Explain market equilibrium.

Discuss the central problems of an economy.

What are the characteristics of a perfectly competitive market?

What is the total product of input?

From the schedule provided below calculate the total revenue, demand curve and the price elasticity of demand:

When do we say that there is an excess demand for a commodity in the market?

What do you mean by the production possibilities of an economy?

How are the total revenue of a firm, market price, and the quantity sold by the firm related to each other?

What are the average fixed cost, average variable cost and average cost of a firm? How are they related? 

Comment on the shape of MR curve in case when TR curve is a

(a) Positively sloped straight line

(b) Horizontal straight line

What do you mean by the production possibilities of an economy?

How does an increase in the price of an input affect the supply curve of a firm?

Briefly explain the concept of the cost function. 

There are three identical firms in a market. The following table shows the supply schedule of firm 1. Compute the market supply schedule.

Considering the same demand curve as in exercise 22, now let us understand for free entry and exit of the firms producing commodity X. Also assume the market consists of identical firms producing commodity X. Let the supply curve of a single firm be explained?

q*= 8+3p for p ≥ 20

= 0 for 0 ≤ p ≤ Rs 20

(a) What is the significance of p =20?

(b) At what price will the market for X be in equilibrium? State the reason for your answer.

(c) Calculate the equilibrium quantity and number of firms. 

Consider a market with two firms. In the following table, columns labelled as SS₁ and SS₂ give the supply schedules of firm 1 and firm 2 respectively. Compute the market supply schedule.

Suppose the demand and supply curve of commodity XX in a perfectly competitive market are given by:

qD =700 - p

qs = 500 + 3p for p ≥ 15

= 0 or 0 ≤ p <15

Assume that the market consists of identical firms. Identify the reason behind the market supply of commodity X being zero at any price less than Rs 15. What will be the equilibrium price for this commodity? At equilibrium, what quantity of X will be produced?

Consider a market with two firms. The following table shows the supply schedules of the two firms: the SS₁ column gives the supply schedule of firm 1 and the SS₂ column gives the supply schedule of firm 2. Compute the market supply schedule.