41.
Assertion (A): The long run cost curve is L-shaped rather than U-shaped.
Reason (R): The new techniques of production of large plants reduce the total costs per unit of output.

45.
Match the following.
List-I List-II
a. Joint demand 1. Tea and Coffee
b. Competitive demand 2. Domestic consumers and industrial users
c. Composite demand 3. Sugar and molasses
d. Joint supply 4. Lipton tea and Brooke Bond tea
e. Competitive supply 5. Car and Petrol

48.
Product variation refers to

50.
According to Lionel Robbins definition of economics, "Economics is a science which . . . . . . . ."