# NCERT Solutions for Class 12 Economics Introductory Microeconomics Chapter 2

## Theory of Consumer Behaviour Class 12

### Exercise : Solutions of Questions on Page Number : 34

Q1 :

What do you mean by the budget set of a consumer?

It refers to the set of consumption bundles that are available to or affordable by the consumer; while being aware of his/her income-level and the existing market prices. Q2 :

What is a budget line?

A budget line represents the different combinations of two goods that are affordable and are available to a consumer; while being aware of his/her income-level and market prices of both the goods.

Let x1 be the amount of good 1.

x2 be the amount of good 2.

P1 be the price of good 1.

P2 be the price of good 2.

P1x1 = Total money spent on good 1

P1x2 = Total money spent on good 2

Then, the budget line will be:

P1x1 + P2x2 = M

All the consumption bundles on the budget line cost the consumer exactly the equivalent of hi/her income.

Q3 :

Explain why the budget line is downward sloping.

Q4 :

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 he/she spends his/her entire income on that good?

(iii) How much of good 2 can be consumed if he/she spends his/her entire income on that good?

(iv) What is the slope of the budget line?

Q5 :

How does the budget line change if the consumer's income increases to Rs 40 but the prices remain unchanged?

Q6 :

How does the budget line change if the price of good 2 decreases by a rupee but the price of good 1 and the consumer's income remain unchanged?

Q7 :

What happens to the budget set if the prices as well as the income double?

Q8 :

Suppose a consumer can afford to buy 6 units of good 1 and 8 units of good 2 if he/she spends her entire income. The prices of two goods are Rs 6 and Rs 8. How much is the consumer's income?

Q9 :

Suppose a consumer wants to consume two goods that 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 a consumer, identify those that cost will him/her exactly Rs 40.

Q10 :

What do you mean by monotonic preferences?

Q11 :

If the consumer has monotonic preferences, then can he/she be indifferent towards bundles (10, 8) and (8, 6)?

Q12 :

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

Q13 :

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

Q14 :

Suppose there are two consumers in the market for a good and their demand functions are as follows:

d1(p) = 20 - p for any price less than or equal to 20 and d1(p) = 0 at any price greater than 20.

d2(p) = 30 - 2p for any price less than or equal to 15 and d1(p) = 0 at any price greater than 15.

Find out the market demand function.

Q15 :

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

D(p) = 10 - 3p for any price less than or equal to and d1(p) = 0 at any price greater than .

What is the market demand function?

Q16 :

Consider a market where there are just two consumers and suppose their demands for the good are given as follows:

Calculate the market demand for the goods.

 p d1 d2 1 2 3 4 5 6 9 8 7 6 5 4 24 20 18 16 14 12

Q17 :

What do you mean by a normal good?

Q18 :

What do you mean by an 'inferior good'? Give some examples.

Q19 :

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

Q20 :

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

Q21 :

Explain price elasticity of demand.

Q22 :

Consider the demand for a good. At price Rs 4, the demand for the good is 25 units. Suppose the price of the good increases to Rs 5, and as a result, the demand for the good falls to 20 units. Calculate the price elasticity.

Q23 :

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

Q24 :

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

Q25 :

Suppose the price elasticity of demand for a good is -0.2. How will the expenditure on the good be affected if there is a 10% increase in its price?