The sole proprietor of the "Books and Children" bookstore receives all accounting profits earned by her firm and a $$28,000-$a$-$year salary she pays herself. She has a standing salary offer of $$35,000$ a year if she agrees to work for a large corporation. If she had invested her capital outside her own company, she estimates that would have returned $$22,000$ a year. Last year, her accounting profit was $$50,000.$a$.$ Calculate her implicit cost.b$.$ Calculate her economic profit.