Final answer:
The monopolist's profit-maximizing output is 10 units and the price is $300.
Step-by-step explanation:
In order to find the monopolist's profit-maximizing output and price, we need to equate the marginal revenue (MR) and marginal cost (MC). By setting MR equal to MC, we can find the quantity at which the monopolist maximizes their profit.
In this case, the MR is given as MR = 400 - 20Q and the MC is given as MC = 20Q. Setting MR = MC, we can solve for the quantity:
400 - 20Q = 20Q → 400 = 40Q → Q = 10
So, the monopolist's profit-maximizing output is 10 units.
To find the price, we can substitute the quantity into the demand curve equation P = 400 - 10Q:
P = 400 - 10(10) = 400 - 100 = 300
Therefore, the monopolist's profit-maximizing output is 10 units and the price is $300.