Final answer:
The equilibrium in the labor market described would be at a wage rate at or above 60, taking into account the fixed adult labor supply of 30 and the additional child labor that would come into play if wages fall below 60.
Step-by-step explanation:
Equilibrium in the Labor Market
Considering the labor market with a labor demand curve described by VMP=100-Ld, where VMP is the value of marginal product and Ld is the quantity of labor demanded, we can determine the market equilibrium. The labor supply of adults is fixed at 30. In addition, there are 40 children, with each child's effective labor supply equivalent to half an adult. If the wage were to fall below 60, all adults will choose to send their children to work, effectively doubling the labor supply with children's lower productivity adjusted.
To find the equilibrium, the supply of labor must equal the demand for labor. In this situation, the equilibrium wage must be set at a rate where no additional workers (adults or children) would enter or leave the market. Considering the scenario provided, all adults will send their children to work if the wage falls below 60, suggesting that the equilibrium wage must be at or above 60 to prevent the influx of children into the labor force.
To calculate exact equilibrium, we set the VMP equal to the wage and solve for Ld. With the presence of only adult workers (30), at a wage of 60, the demand would be VMP=100-Ld, Ld = 40 (100-60). However, if wages drop, children will enter the market, and the calculation will be different since each child is equivalent to half an adult. The effective adult-equivalent labor supply would then be 30 adults + (40 children * 0.5) = 50.