Final answer:
The marginal cost for producing the 301st unit, when total cost increases from $400 to $500, is $100. Marginal cost is an essential aspect of pricing and production decisions, impacting profitability.
Step-by-step explanation:
The marginal cost of production is the additional cost incurred to produce an additional unit of a product. To calculate this, we take the change in total cost and divide it by the change in quantity. Using the example provided, if the total cost for producing 300 units is $400 and increases to $500 for producing 301 units, the marginal cost for the additional unit produced would be calculated as follows:
$500 - $400 = $100
Thus, the marginal cost of producing the 301st unit is $100.
In other provided examples, if total cost increases from $1500 for one unit to $1800 for two, the marginal cost is calculated by the increase in the total cost divided by the increase in quantity (2 units - 1 unit = 1 unit):
$1800 - $1500 = $300
Therefore, the marginal cost of the second unit is $300. It is crucial for businesses to consider marginal costs in their pricing and production decisions as it impacts profitability. For instance, producing a unit with a marginal cost of $250 when the marginal revenue is $600 increases overall profits, but if marginal cost equals marginal revenue, as in the case when both are $400, producing additional units wouldn't add to profits.