Firm1, on the other hand, will earn a profit of only
//~1 = P1Q1-20 = (6)[12-(2)(6)+4]-20 =$4
So if Firm1 charges $6 but Firm2 charges only $4 Firm 2's profit will increase to $20. And it will do so at the expense of Firm 1's profit, which will fall to $4. Clearly, Firm2 does best by charging only $