I'm struggling with the per unit fee

You are the manager of a monopoly. A typical consumer's inverse demand function for your firm's product is P= 250 - 40Q, and your cost function is C(Q) = 10Q. a. Determine the optimal two-part pricing strategy. Per-unit fee: $ X Fixed fee: $ 720 b. How much additional profit do you earn using a two-part pricing strategy compared with charging this consumer a per- unit price? 360