If investment increases from 400 to 550 and income increases from 900 to 1,650, the MPS should be
Equal to :
(a) 0.1 (b) 0.2 (c) 0.3 (d) 0.4
Answers
Answer:
Question 1. Measure the level of ex-ante aggregate demand when autonomous investment and consumption expenditure (A) is Rs 50 crores, and MPS is 0.2 and level of income (Y) is Rs 4000 crores. State whether the economy is in equilibrium or not (cite reasons).[3-4 Marks]
Answer: As given in the examination problem, Equilibrium Income (Y) = Rs 4000 crore Autonomous Investment + Autonomous Consumption  = Rs 50 crore MPS = 0.2
So, MPC(b) = 1 – 0.2 = 0.8
(MPC = 1 – MPS)
AD = C + I
AD =  + bY + I =  + bY
= 50 + 0.8Y 
As we know, the equilibrium level of national income in two-sector model is determined where,
AS = AD
Y = 50 + 0.8Y
4000 = 50 + 0.8(4000)
4000 = 50 + 3200
4000 =3250
Hence, the economy is not in equilibrium.
Question 2. Explain ‘Paradox of Thrift’.[3-4 Marks]
Answer:
The term thrift means savings and the paradox of thrift shows how an attempt by the economy as a whole to save more out of its current income will ultimately result in lower savings for the economy.
If all the people in the economy make an effort to save more, then the total savings of the community will not increase, on the contrary they will decrease. This is called the paradox of thrift.
Reasons for “Paradox of thrift” to operate:
(a) As we know that one person’s expenditure is another person’s income.
(b) If individual ‘A’ decides to save more by reducing his consumption expenditure, the income of individual ‘B’ will be less and individual ‘B’ in turn will spend less.
(c) Thus, if all individuals in the economy decide to save more, the income received by each individual will be less and overall income will fall and also lower will be the total savings.
Diagram Representation:

In the above figure , we have induced investment function which makes the investment curve upward positively sloping. With the increase in savings, not only the equilibrium income falls, but also savings decline.
Question 3. What is Effective Demand? How will you derive the autonomous expenditure multiplier when price of final goods and the rate of interest are given?[6 Marks]
Answer:
The level at which the economy is in equilibrium, i.e., where aggregate demand = aggregate supply, is called effective demand.
Under fixed price model, the value of planned (ex-ante) aggregate demand for final goods AD is equal to ex-ante consumption plus ex-ante investment expenditure.
AD = C + I =  + bY + 
=  + bY
 = 2 of all autonomous variable, i.e., )
As we know that the equilibrium level of national income in two sector model is determined where,
AS = AD
Y=+bY=
Diagrammatical representation,

In the above mentioned diagram, aggregate demand is measured on vertical axis and national income is measured on horizontal axis. Initially, at autonomous expenditure , the equilibrium level of national income OY is determined at point E. But due to increase in autonomous expenditure from  to , the aggregate demand curve shifts upward from AD to A and at the same level of national income, i.e., OY, aggregate demand is greater than aggregate supply. Production will have to be increase to meet the excess demand. Consequently, national income will increase from OY to O As, we know positive relationship exists between national income and consumption, so consumption will increase which will, increase the new aggregate demand A , till we reach the new equilibrium level of output i.e., O at 
MORE QUESTIONS SOLVED
I.Very Short Answer Type Questions (1 Mark)
Question 1. If planned savings are greater than planned investments, what will be its effect on inventories? [CBSB Sample Paper 2008]
Answer: The inventories will rise.
Question 2. What is meant by effective demand?
Answer: The level at which the economy is in equilibrium, i.e., where aggregate demand = aggregate supply, is called effective demand.
Question 3. Define the term ‘multiplier’. How do we measure it?
Answer: The ratio of change in national income () due to change in investment () is known as multiplier (K).
(K)=
Question 4. An increase of Rs 1000 crore in invest¬ment leads to a rise of Rs 5000 crore in the national income. Calculate the value of multiplier.
Answer: Multiplier (k)=
= =Rs 5