Final answer:
A monopolistic competitor determines the profit-maximizing quantity by comparing marginal revenue and marginal cost.
Step-by-step explanation:
A monopolistic competitor determines how much to produce and at what price by analyzing the demand and cost conditions. Total revenue is calculated by multiplying the price and quantity at each point on the demand curve.
Marginal revenue is the change in total revenue divided by the change in quantity. Total cost, marginal cost, and average cost can be calculated using the change in total cost and quantity. By comparing marginal revenue and marginal cost, the firm can determine the profit-maximizing quantity.