Please refer to the following question:

Q5 (4 marks). Two rms compete in a market by selling imperfect substitutes (i.e., differentiated products). The demand equations for each rm are given by the following equations: '11 = 50 'PI +P2 '12 = 50 'P2 +P1 a (2 marks). Suppose the marginal cost of each rm is $10 and both rms compete by simultaneously choosing price. Calculate the Bertrand-Nash equilibrium price, gugntity and prots of each fum. b (2 marks). Suppose rm l's marginal cost has increased to $20, but rm 2's marginal cost stays at $10. Calculate the Berqqnd-Nqsh equilibrium price, Quantity and prots of each rm. If both rms sell perfect substitutes, what would be the Bertrand-Nash equilibrium