4. Consider two companies, Company A and Company B, producing the same model of iPhones. The demand for the iPhones produced by Company A is D A, and the demand for the iPhones produced by Company B is D3. The demands are described by the following functions: DA=200PA(PAP) (l) D3=QUUPB(PBP) (2) where PA and P3 are the prices of iPhones for Factory A and Factory B respectively, and P is the average price over the prices PA and PB. For each company, the cost for producing one iPhone is C = 20. Suppose that each company can only choose one of the three prices {61], 70,80} for a sale. (a) Compute the prots of each company under all sale price combinations and produce the payoff matrix for each company. int: t epro t = t e eman or t ei ones X t e pro t o onei one er e. h h (1 cl f h Ph h E f Ph aft sal [10 Marks] (b) Find the Nash equilibrium of this game. What are the prots at this equilibrium? Explain your reason clearly. [5 Marks] (C) If the cost 0 doubles to C = 40, would the Nash equilibrium from part (b) change? Give clear reasons. [5 Marks]