Please help?

Question 7 (Challenging). Consider three housemates: Mitchell, Paul and Achini. They are deciding how many hours per day to run the air conditioning in their apartment. Collectively, their aggregate demand for air conditioning hours is P = 12 % where Q is in hours. Individually, Mitchell demands P = 8 g and Paul demands P = 3 g. a) Find Achini's individual demand for air conditioning. b) If the marginal cost of running the air conditioning for an additional hour is $2, how much air conditioning will Mitchell, Paul and Achini demand if they individually and independently decide? c) What is the socially optimal number of hours to run the air conditioning for in their apartment? d) Calculate the DWL from not consuming this quantity. e) What are Mitchell, Paul and Achini's Lindahl prices for the socially optimal quantity