Marginal cost (MC) is defined as the additional cost incurred from producing one more unit of output. It is crucial for understanding how production decisions affect overall costs. To calculate marginal cost, we can use the formula:

$$ MC = \frac{\Delta \text{Total Cost}}{\Delta \text{Quantity}} $$

In practical scenarios, such as when hiring additional workers, the output may increase by more than one unit. Therefore, we assess the average change in total cost over the change in quantity produced. For instance, if hiring one worker increases total cost from $100 to $180, the change in total cost is $80. This process continues as more workers are added, with the total cost reflecting only variable costs associated with labor, while fixed costs remain constant.

As we calculate the marginal cost for each additional worker, we observe the following changes in quantity and corresponding marginal costs:

• 1st worker: Change in total cost = $80, Change in quantity = 30 pizzas, MC = $2.67 per pizza
• 2nd worker: Change in total cost = $80, Change in quantity = 50 pizzas, MC = $1.60 per pizza
• 3rd worker: Change in total cost = $80, Change in quantity = 70 pizzas, MC = $1.14 per pizza
• 4th worker: Change in total cost = $80, Change in quantity = 30 pizzas, MC = $2.67 per pizza
• 5th worker: Change in total cost = $80, Change in quantity = 10 pizzas, MC = $8.00 per pizza

The marginal cost curve typically exhibits a U-shape. Initially, as more units are produced, marginal costs decrease due to increasing marginal product of labor. However, after reaching a certain point, diminishing returns set in, causing marginal costs to rise sharply. This relationship highlights that when the marginal product of labor increases, marginal costs decrease, and vice versa.

In summary, understanding marginal cost is essential for making informed production decisions. It allows businesses to evaluate the cost-effectiveness of increasing output and helps in optimizing resource allocation. The U-shaped marginal cost curve serves as a visual representation of the relationship between production levels and costs, illustrating the dynamics of increasing and decreasing returns in production.