Solution :
A firm hires labor till a point where the cost of hiring is equal to the value of the additional revenue it produces.
We know ,
the wage rate = cos of hiring an additional worker
the value of the additional revenue that the firm produces = price x (MPI) marginal product of the labor.
Therefore, the firm will hire when :
Wage = value of the additional revenue it generates
Thus, wage = price x (MPI) marginal product of the labor ...........(i)
Therefore, given :
wage of a worker = $ 45
Price = $ 12
So, 45 = 12 x MPI
MPI = 3.8
So the marginal product of employing three days of labor = 25-18/4-3 = 7
Marginal product of employing four days of labor = 30-25/4-3 = 5
So the 4th day produces less revenue than the cost that it generates.
So, the firm should hire 3 workers.
