Professor Rush decides to quit teaching economics and opens a shoe store out at the mall. He gave up an annual income of $50,000 to open the store. A year after opening the shoe store, the total revenue for the year was $200,000. Rush's expenses were $30,000 for labor, rent was $18,000, and utilities were $1,200. He also had to purchase new shoes from manufacturers, at a cost of $60,000, which was financed by cashing in his savings of $60,000 that had been in a bank earning 8 percent per year. The normal profit from operating a shoe store in the mall is $20,000

Determine Professor Rush's explicit costs, implicit costs and economic profits. (steps required)