Final answer:
Equilibrium occurs where labor supply equals labor demand. Initially, the equilibrium wage is $11 with an employment level of 50. After the supply shift, the new equilibrium wage is $10 with 60 workers employed.
Step-by-step explanation:
To calculate the equilibrium level of employment and wage rate in a labor market, we set the labor supply (Ls) equal to the labor demand (LD). For the initial labor curves provided, Ls = -60+ 10W and LD = 160 - 10W, we solve for W and get the equilibrium wage. At equilibrium, Ls equals LD, thus:
-60 + 10W = 160 - 10W which simplifies to 20W = 220, so the equilibrium wage W is $11. The corresponding equilibrium level of employment is Ls or LD evaluated at W = 11, which is 50.
For the size of the labor force in equilibrium, we simply use the sum of employed workers and the unemployed. Since in equilibrium unemployment is 0, the labor force is the number of employed workers, which would be 50.
After the supply curve shifts following migration, the new Ls becomes -40 + 10W. Setting it equal to the initial LD, we solve the equation -40 + 10W = 160 - 10W, which gives us 20W = 200, resulting in an equilibrium wage of $10. The corresponding employment level is 60 workers.
To calculate economic rent, we need more information typically defined as the difference between what workers are paid and what they would be willing to accept. Since this information is not provided, the economic rent cannot be calculated based on the given data.