When two goods are involved, a rational consumer maximises utility where

Here are the solutions to the questions:

23. When two goods are involved, a rational consumer maximizes utility where the marginal utility per dollar spent is equal for both goods. This is represented by the formula: $\frac{MU_X}{P_X} = \frac{MU_Y}{P_Y}$

• The correct option is A. $$\boxed{\text{A. } \frac{MUX}{PX} = \frac{MUY}{PY}}$$

24. A fixed cost is a cost that does not change with the level of output in the short run. Rent on land is typically a payment that remains constant regardless of how much is produced.

• The correct option is A. $$\boxed{\text{A. Rent on land}}$$

25. The efficacy of economic development plans in Nigeria has often been hampered by political instability and frequent changes in government, leading to policy inconsistencies and abandonment of long-term strategies.

• The correct option is D. $$\boxed{\text{D. frequent changes in government}}$$

26. Human capital refers to the skills, knowledge, and experience possessed by individuals. Providing training to personnel directly enhances these attributes, thereby improving human capital.

• The correct option is A. $$\boxed{\text{A. personnels training}}$$

27. In the long run, all factors of production are considered variable, meaning their quantities can be adjusted by the firm.

• The correct option is C. $$\boxed{\text{C. variable}}$$

28. Total Revenue (TR) is maximized when Marginal Revenue (MR) equals zero. Beyond this point, if MR becomes negative, TR will start to decrease.

• The correct option is E. $$\boxed{\text{E. at its maximum}}$$

29. An oligopolistic market is characterized by a small number of large producers. This limited number is often due to significant barriers to entry, such as the large capital requirements needed to start a business in such an industry.

• The correct option is D. $$\boxed{\text{D. large capital requirement}}$$

30. The efficiency of labour, which is the output produced per worker, can be significantly improved by providing good working conditions. This includes a safe environment, fair treatment, and adequate resources, all of which contribute to higher productivity and morale.

• The correct option is A. $$\boxed{\text{A. good working condition}}$$

31. Human capital can be enhanced by improving the health, education, and skills of the population. The provision of better health services directly contributes to a healthier workforce, which is more productive and capable of learning, thus enhancing human capital.

• The correct option is E. $$\boxed{\text{E. provision of better health services}}$$