Pam runs a hot dog cart at the sports stadium. Pam has no​ skills, no job​ experience, and no alternative employment. Entrepreneurs in the hot dog cart business earn ​$20,000 a year. Pam pays the rent of ​$500 a​ year, and her total revenue is ​$16,000 a year. She borrowed ​$1,100 at 10 percent a year to buy equipment. At the end of one​ year, Pam was offered ​$1,000 for her business and all its equipment. Pam explicit cost are ____.