Merlin wants to make more money selling fake beards this month than he did last month. all black beards in his shop cost the same amount of money, and all red beards in his shop cost $25. let b represent the number of black beards and r represent the number of red beards that merlin can sell to make more money than he made last month. 20b+25r > 350 according to the inequality, how much money did merlin make last month, and how much does each black beard cost?