21.
Returns to scale involve variations in the quantities of the various factors of production
1. Simultaneously
2. Proportionately

24.
"The law of diminishing return is merely a matter of logical necessity but the law of increasing return is a matter of empirical fact." The statement comes from

25.
Which of the following equation is correct?

27.
Match the following.
List-I List-II
a. Responsiveness of demand to change in price 1. Income elasticity of demand
b. Responsiveness of demand to change in tastes 2. Price elasticity of demand
c. Responsiveness of demand to change in income 3. Cross elasticity of demand
d. Responsiveness of demand to change in price of related goods 4. Taste elasticity of demand