Can you explain this problem to me please?

Suppose Die Cast Aluminum Co. is a subcontractor for the auto industry and makes specialized auto parts. There is a bracket it manufactures that it sells for $2.50. The following table shows the number of brackets that can be produced from a given number of labor hours. Assume that the company cannot hire labor for a fraction of an hour.

Hours of Labor Output

0 0

1 50

2 90

3 120

4 140

5 150

6 155

7 157

The marginal product of labor for the fourth hour of labor is

20

The value of the marginal product of labor for the fourth hour of labor is

50

If the wage paid to workers in DieCast's plant is$25/hour, it should employ

5 workers

If the wage paid to workers in DieCast's plant is$35/hour, it should employ

4

If the wage is$25/hour, but the price of a bracket declines to $2.00, it should employ

4