I'm not sure if I've done my solutions correctly

Exercise 2. (6 marks) Little Italy has 100 consumers all of whom buy either one pizza or nothing. Each consumer has a reservation price of $15. That is, each consumer is willing to pay at most $15 for a pizza. There are two pizza stores - A and B - located next to each other. It costs $7 to make a pizza. Let pa and pb denote the price charged by stores A and B respectively. For simplicity, assume Pi E {12,15} for both 1' : A, B (we omit the dollar signs for simplicity). If p,-